Download LTC2162/LTC2161/LTC2160 - 16-Bit, 65Msps/ 40Msps/25Msps Low

LTC2162/LTC2161/LTC2160
16-Bit, 65Msps/
40Msps/25Msps
Low Power ADCs
Description
Features
n
n
n
n
n
n
n
n
n
n
n
n
77dB SNR
90dB SFDR
Low Power: 87mW/63mW/45mW
Single 1.8V Supply
CMOS, DDR CMOS, or DDR LVDS Outputs
Selectable Input Ranges: 1VP-P to 2VP-P
550MHz Full Power Bandwidth S/H
Optional Data Output Randomizer
Optional Clock Duty Cycle Stabilizer
Shutdown and Nap Modes
Serial SPI Port for Configuration
48-Pin (7mm × 7mm) QFN Package
The LTC®2162/LTC2161/LTC2160 are sampling 16-bit A/D
converters designed for digitizing high frequency, wide
dynamic range signals. They are perfect for demanding
communications applications with AC performance that
includes 77dB SNR and 90dB spurious free dynamic range
(SFDR). Ultralow jitter of 0.07psRMS allows undersampling
of IF frequencies with excellent noise performance.
DC specs include ±2LSB INL (typ), ±0.5LSB DNL (typ)
and no missing codes over temperature. The transition
noise is 3.3LSBRMS.
The digital outputs can be either full rate CMOS, double
data rate CMOS, or double data rate LVDS. A separate
output power supply allows the CMOS output swing to
range from 1.2V to 1.8V.
Applications
Communications
Cellular Base Stations
n Software Defined Radios
n Portable Medical Imaging
n Multichannel Data Acquisition
n Nondestructive Testing
The ENC+ and ENC– inputs may be driven differentially
or single-ended with a sine wave, PECL, LVDS, TTL, or
CMOS inputs. An optional clock duty cycle stabilizer allows high performance at full speed for a wide range of
clock duty cycles.
n
n
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
Typical Application
1.8V
VDD
2-Tone FFT, fIN = 70MHz and 69MHz
1.8V
OVDD
0
–10
–20
S/H
–30
16-BIT
ADC CORE
OUTPUT
DRIVERS
125MHz
216210 TA01a
GND
CMOS
DDR CMOS OR
DDR LVDS
OUTPUTS
–40
–50
–60
–70
–80
–90
–100
CLOCK
CONTROL
CLOCK
D15
•
•
•
D0
AMPLITUDE (dBFS)
ANALOG
INPUT
–110
–120
OGND
0
20
10
FREQUENCY (MHz)
30
2162 TA01b
216210f
1
LTC2162/LTC2161/LTC2160
Absolute Maximum Ratings
(Notes 1, 2)
Supply Voltages (VDD, OVDD)........................ –0.3V to 2V
Analog Input Voltage (AIN+, AIN –, PAR/SER, SENSE)
(Note 3).................................... –0.3V to (VDD + 0.2V)
Digital Input Voltage (ENC+, ENC–, CS, SDI, SCK)
(Note 4)................................................. –0.3V to 3.9V
SDO (Note 4).............................................. –0.3V to 3.9V
Digital Output Voltage.................–0.3V to (OVDD + 0.3V)
Operating Temperature Range
LTC2162C, LTC2161C, LTC2160C.............. 0°C to 70°C
LTC2162I, LTC2161I, LTC2160I.............–40°C to 85°C
Storage Temperature Range................... –65°C to 150°C
Pin Configuration
FULL RATE CMOS OUTPUT MODE
DOUBLE DATA RATE CMOS OUTPUT MODE
TOP VIEW
48 VDD
47 VDD
46 SENSE
45 VREF
44 SDO
43 GND
42 OF
41 DNC
40 D15
39 D14
38 D13
37 D12
48 VDD
47 VDD
46 SENSE
45 VREF
44 SDO
43 GND
42 OF
41 DNC
40 D14_15
39 DNC
38 D12_13
37 DNC
TOP VIEW
VCM 1
AIN + 2
AIN – 3
GND 4
REFH 5
REFL 6
REFH 7
REFL 8
PAR/SER 9
GND 10
GND 11
VDD 12
49
GND
VDD 13
GND 14
ENC + 15
ENC – 16
CS 17
SCK 18
SDI 19
GND 20
DNC 21
D0_1 22
DNC 23
D2_3 24
49
GND
36 D11
35 D10
34 D9
33 D8
32 OVDD
31 OGND
30 CLKOUT +
29 CLKOUT –
28 D7
27 D6
26 D5
25 D4
VDD 13
GND 14
ENC + 15
ENC – 16
CS 17
SCK 18
SDI 19
GND 20
D0 21
D1 22
D2 23
D3 24
VCM 1
AIN + 2
AIN – 3
GND 4
REFH 5
REFL 6
REFH 7
REFL 8
PAR/SER 9
GND 10
GND 11
VDD 12
UK PACKAGE
48-LEAD (7mm × 7mm) PLASTIC QFN
UK PACKAGE
48-LEAD (7mm × 7mm) PLASTIC QFN
TJMAX = 150°C, θJA = 29°C/W
EXPOSED PAD (PIN 49) IS GND, MUST BE SOLDERED TO PCB
36 D10_11
35 DNC
34 D8_9
33 DNC
32 OVDD
31 OGND
30 CLKOUT +
29 CLKOUT –
28 D6_7
27 DNC
26 D4_5
25 DNC
TJMAX = 150°C, θJA = 29°C/W
EXPOSED PAD (PIN 49) IS GND, MUST BE SOLDERED TO PCB
216210f
2
LTC2162/LTC2161/LTC2160
pin configuration
DOUBLE DATA RATE LVDS OUTPUT MODE
48 VDD
47 VDD
46 SENSE
45 VREF
44 SDO
43 GND
42 OF +
41 OF –
40 D14_15 +
39 D14_15 –
38 D12_13 +
37 D12_13 –
TOP VIEW
VCM 1
AIN + 2
AIN – 3
GND 4
REFH 5
REFL 6
REFH 7
REFL 8
PAR/SER 9
GND 10
GND 11
VDD 12
36 D10_11 +
35 D10_11 –
34 D8_9 +
33 D8_9 –
32 OVDD
31 OGND
30 CLKOUT +
29 CLKOUT –
28 D6_7 +
27 D6_7–
26 D4_5 +
25 D4_5–
VDD 13
GND 14
ENC + 15
ENC – 16
CS 17
SCK 18
SDI 19
GND 20
D0_1 – 21
D0_1 + 22
D2_3 – 23
D2_3 + 24
49
GND
UK PACKAGE
48-LEAD (7mm × 7mm) PLASTIC QFN
TJMAX = 150°C, θJA = 29°C/W
EXPOSED PAD (PIN 49) IS GND, MUST BE SOLDERED TO PCB
order information
LEAD FREE FINISH
TAPE AND REEL
PART MARKING*
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LTC2162CUK#PBF
LTC2162CUK#TRPBF
LTC2162UK
48-Lead (7mm × 7mm) Plastic QFN
0°C to 70°C
LTC2162IUK#PBF
LTC2162IUK#TRPBF
LTC2162UK
48-Lead (7mm × 7mm) Plastic QFN
–40°C to 85°C
LTC2161CUK#PBF
LTC2161CUK#TRPBF
LTC2161UK
48-Lead (7mm × 7mm) Plastic QFN
0°C to 70°C
LTC2161IUK#PBF
LTC2161IUK#TRPBF
LTC2161UK
48-Lead (7mm × 7mm) Plastic QFN
–40°C to 85°C
LTC2160CUK#PBF
LTC2160CUK#TRPBF
LTC2160UK
48-Lead (7mm × 7mm) Plastic QFN
0°C to 70°C
LTC2160IUK#PBF
LTC2160IUK#TRPBF
LTC2160UK
48-Lead (7mm × 7mm) Plastic QFN
–40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
216210f
3
LTC2162/LTC2161/LTC2160
converter
Characteristics l denotes the specifications which apply over the full operating
The
temperature range, otherwise specifications are at TA = 25°C.
LTC2162
PARAMETER
CONDITIONS
Resolution (No Missing Codes)
MIN
LTC2161
TYP
MAX
MIN
LTC2160
TYP
MAX
MIN
MAX
UNITS
l
16
Integral Linearity Error
Differential Analog Input
(Note 6)
l
–6
±2
6
–6
±2
6
–6
±2
6
LSB
Differential Linearity Error
Differential Analog Input
l
–0.9
±0.5
0.9
–0.9
±0.5
0.9
–0.9
±0.5
0.9
LSB
Offset Error
(Note 7)
l
–7
±1.5
7
–7
±1.5
7
–7
±1.5
7
mV
Gain Error
Internal Reference
External Reference
–1.8
±1.5
–0.5
–1.8
±1.5
–0.5
–1.8
±1.5
–0.5
0.8
%FS
%FS
l
16
TYP
Offset Drift
0.8
16
0.8
Bits
±10
±10
±10
µV/°C
Full-Scale Drift
Internal Reference
External Reference
±30
±10
±30
±10
±30
±10
ppm/°C
ppm/°C
Transition Noise
External Reference
3.3
3.3
3.2
LSBRMS
The
Analog
input l denotes the specifications which apply over the full operating temperature range, otherwise
specifications are at TA = 25°C. (Note 5)
SYMBOL
PARAMETER
CONDITIONS
VIN
Analog Input Range (AIN+ – AIN– )
MIN
TYP
MAX
UNITS
1.7V < VDD < 1.9V
l
VIN(CM)
Analog Input Common Mode (AIN+ + AIN– )/2
Differential Analog Input (Note 8)
l
0.7
VCM
1.25
V
VSENSE
External Voltage Reference Applied to SENSE
External Reference Mode
l
0.625
1.250
1.300
V
IINCM
Analog Input Common Mode Current
Per Pin, 65Msps
Per Pin, 40Msps
Per Pin, 25Msps
IIN1
Analog Input Leakage Current (No Encode)
0 < AIN+, AIN– < VDD
l
–1
1
µA
IIN2
PAR/SER Input Leakage Current
0 < PAR/SER < VDD
l
–3
3
µA
IIN3
SENSE Input Leakage Current
0.625 < SENSE < 1.3V
l
–3
3
µA
tAP
Sample-and-Hold Acquisition Delay Time
tJITTER
Sample-and-Hold Acquisition Delay Jitter
CMRR
Analog Input Common Mode Rejection Ratio
BW-3B
Full Power Bandwidth
1 to 2
VP-P
104
64
40
µA
µA
µA
0
Single-Ended Encode
Differential Encode
ns
0.07
0.09
Figure 6 Test Circuit
psRMS
80
dB
550
MHz
The
dynamic
accuracy l denotes the specifications which apply over the full operating temperature range,
otherwise specifications are at TA = 25°C. AIN = –1dBFS. (Note 5)
LTC2162
SYMBOL PARAMETER
CONDITIONS
SNR
5MHz Input
30MHz Input
70MHz Input
140MHz Input
SFDR
Signal-to-Noise Ratio
Spurious Free Dynamic Range 5MHz Input
2nd Harmonic
30MHz Input
70MHz Input
140MHz Input
MIN
l
75.4
l
82
TYP
77.0
76.9
76.8
76.3
90
90
89
84
LTC2161
MAX
MIN
75.3
83
TYP
76.9
76.8
76.7
76.2
90
90
89
84
LTC2160
MAX
MIN
75.5
83
TYP
MAX
UNITS
77.1
77.0
76.9
76.4
dBFS
dBFS
dBFS
dBFS
90
90
89
84
dBFS
dBFS
dBFS
dBFS
216210f
4
LTC2162/LTC2161/LTC2160
The
dynamic
accuracy l denotes the specifications which apply over the full operating temperature range,
otherwise specifications are at TA = 25°C. AIN = –1dBFS. (Note 5)
LTC2162
SYMBOL PARAMETER
SFDR
SFDR
CONDITIONS
Spurious Free Dynamic Range 5MHz Input
3rd Harmonic
30MHz Input
70MHz Input
140MHz Input
Spurious Free Dynamic Range 5MHz Input
4th Harmonic or Higher
30MHz Input
70MHz Input
140MHz Input
S/(N+D) Signal-to-Noise Plus
Distortion Ratio
5MHz Input
30MHz Input
70MHz Input
140MHz Input
MIN
l
83
l
88
l
75
TYP
LTC2161
MAX
90
90
89
84
MIN
84
95
95
95
95
89
76.8
76.7
76.4
76.3
75
TYP
LTC2160
MAX
90
90
89
84
MIN
TYP
84
95
95
95
95
89
76.7
76.6
76.3
75.2
74.9
MAX
UNITS
90
90
89
84
dBFS
dBFS
dBFS
dBFS
95
95
95
95
dBFS
dBFS
dBFS
dBFS
76.9
76.8
76.5
76.4
dBFS
dBFS
dBFS
dBFS
The
internal
reference characteristics l denotes the specifications which apply over the
full operating temperature range, otherwise specifications are at TA = 25°C. (Note 5)
PARAMETER
CONDITIONS
VCM Output Voltage
IOUT = 0
MIN
TYP
MAX
0.5•VDD – 25mV
0.5•VDD
0.5•VDD + 25mV
VCM Output Temperature Drift
UNITS
±25
VCM Output Resistance
–600µA < IOUT < 1mA
VREF Output Voltage
IOUT = 0
ppm/°C
4
1.225
Ω
1.250
VREF Output Temperature Drift
1.275
V
±25
VREF Output Resistance
–400µA < IOUT < 1mA
VREF Line Regulation
1.7V < VDD < 1.9V
V
ppm/°C
7
Ω
0.6
mV/V
The
digital
inputs and outputs l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. (Note 5)
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
ENCODE INPUTS (ENC+, ENC–)
DIFFERENTIAL ENCODE MODE (ENC– NOT TIED TO GND)
VID
Differential Input Voltage
(Note 8)
l
0.2
VICM
Common Mode Input Voltage
Internally Set
Externally Set (Note 8)
l
1.1
l
0.2
V
1.2
1.6
V
V
3.6
V
VIN
Input Voltage Range
ENC+, ENC– to GND
RIN
Input Resistance
(See Figure 10)
10
kΩ
CIN
Input Capacitance
(Note 8)
3.5
pF
SINGLE-ENDED ENCODE MODE (ENC– TIED TO GND)
VIH
High Level Input Voltage
VDD = 1.8V
l
VIL
Low Level Input Voltage
VDD = 1.8V
l
1.2
V
VIN
Input Voltage Range
ENC+ to GND
l
RIN
Input Resistance
(See Figure 11)
30
kΩ
CIN
Input Capacitance
(Note 8)
3.5
pF
0
0.6
V
3.6
V
216210f
5
LTC2162/LTC2161/LTC2160
digital inputs and outputs
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. (Note 5)
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
DIGITAL INPUTS (CS, SDI, SCK in Serial or Parallel Programming Mode. SDO in Parallel Programming Mode)
VIH
High Level Input Voltage
VDD = 1.8V
l
VIL
Low Level Input Voltage
VDD = 1.8V
l
IIN
Input Current
VIN = 0V to 3.6V
l
CIN
Input Capacitance
(Note 8)
1.3
V
–10
0.6
V
10
µA
3
pF
200
Ω
SDO OUTPUT (Serial Programming Mode. Open Drain Output. Requires 2kΩ Pull-Up Resistor if SDO is Used)
ROL
Logic Low Output Resistance to GND
VDD = 1.8V, SDO = 0V
IOH
Logic High Output Leakage Current
SDO = 0V to 3.6V
COUT
Output Capacitance
(Note 8)
l
–10
10
µA
3
pF
1.790
V
DIGITAL DATA OUTPUTS (CMOS MODES: FULL DATA RATE AND DOUBLE DATA RATE)
OVDD = 1.8V
VOH
High Level Output Voltage
IO = –500µA
l
1.750
VOL
Low Level Output Voltage
IO = 500µA
l
VOH
High Level Output Voltage
IO = –500µA
1.488
V
VOL
Low Level Output Voltage
IO = 500µA
0.010
V
VOH
High Level Output Voltage
IO = –500µA
1.185
V
VOL
Low Level Output Voltage
IO = 500µA
0.010
V
0.010
0.050
V
OVDD = 1.5V
OVDD = 1.2V
DIGITAL DATA OUTPUTS (LVDS MODE)
VOD
Differential Output Voltage
100Ω Differential Load, 3.5mA Mode
100Ω Differential Load, 1.75mA Mode
l
247
350
175
454
VOS
Common Mode Output Voltage
100Ω Differential Load, 3.5mA Mode
100Ω Differential Load, 1.75mA Mode
l
1.125
1.250
1.250
1.375
RTERM
On-Chip Termination Resistance
Termination Enabled, OVDD = 1.8V
mV
mV
V
V
100
Ω
power requirements
The l denotes the specifications which apply over the full operating temperature
range, otherwise specifications are at TA = 25°C. (Note 9)
LTC2162
SYMBOL
PARAMETER
CONDITIONS
LTC2161
LTC2160
MIN
TYP
MAX
MIN
TYP
MAX
MIN
TYP
MAX
1.8
1.9
1.7
1.8
1.9
1.7
1.8
1.9
1.8
1.9
1.1
1.8
1.9
1.1
48.3
49.6
54
35.2
35.8
39
UNITS
CMOS Output Modes: Full Data Rate and Double Data Rate
VDD
Analog Supply Voltage (Note 10)
l
1.7
OVDD
Output Supply Voltage (Note 10)
l
1.1
IVDD
Analog Supply Current DC Input
Sine Wave Input
l
IOVDD
Digital Supply Current Sine Wave Input, OVDD =1.2V
PDISS
Power Dissipation
DC Input
Sine Wave Input, OVDD =1.2V
2.6
l
1.6
87
92
97.5
1.8
1.9
V
25.0
25.4
28.5
mA
mA
1.0
63
66
70.5
V
mA
45
47
51.5
mW
mW
LVDS Output Mode
VDD
Analog Supply Voltage (Note 10)
l
1.7
1.8
1.9
1.7
1.8
1.9
1.7
1.8
1.9
V
OVDD
Output Supply Voltage (Note 10)
l
1.7
1.8
1.9
1.7
1.8
1.9
1.7
1.8
1.9
V
216210f
6
LTC2162/LTC2161/LTC2160
power requirements
The l denotes the specifications which apply over the full operating temperature
range, otherwise specifications are at TA = 25°C. (Note 9)
LTC2162
SYMBOL
PARAMETER
IVDD
Analog Supply Current Sine Wave Input 1.75mA Mode
3.5mA Mode l
CONDITIONS
MIN
50.3
51.1
IOVDD
Digital Supply Current Sine Wave Input 1.75mA Mode
(OVDD = 1.8V)
3.5mA Mode l
PDISS
Power Dissipation
Sine Wave Input, 1.75mA Mode
Sine Wave Input, 3.5mA Mode
TYP
l
LTC2161
MAX
MIN
TYP
LTC2160
TYP
MAX
42
26.8
27.7
31
mA
mA
21.4
41.1
46
21.1
40.9
46
mA
mA
106
143
159
86
123
139
mW
mW
57
37.3
38.2
21.5
41.2
46
129
166
186
MAX
MIN
UNITS
All Output Modes
PSLEEP
Sleep Mode Power
1
1
1
mW
PNAP
Nap Mode Power
10
10
10
mW
PDIFFCLK
Power Increase with Differential Encode Mode Enabled
(No Increase for Nap or Sleep Modes)
20
20
20
mW
timing characteristics
The l denotes the specifications which apply over the full operating temperature
range, otherwise specifications are at TA = 25°C. (Note 5)
LTC2162
SYMBOL
PARAMETER
CONDITIONS
fS
Sampling Frequency
(Note 10)
tL
MIN
l
1
ENC Low Time (Note 8) Duty Cycle Stabilizer Off
Duty Cycle Stabilizer On
l
l
7.3
2
tH
ENC High Time (Note 8) Duty Cycle Stabilizer Off
Duty Cycle Stabilizer On
l
l
7.3
2
tAP
Sample-and-Hold
Acquisition Delay Time
SYMBOL
PARAMETER
TYP
LTC2161
MAX
MIN
65
1
7.69
7.69
500
500
11.88
2
7.69
7.69
500
500
11.88
2
0
TYP
LTC2160
MAX
MIN
40
1
12.5
12.5
500
500
19
2
12.5
12.5
500
500
19
2
0
CONDITIONS
TYP
MAX
UNITS
25
MHz
20
20
500
500
ns
ns
20
20
500
500
ns
ns
0
ns
MIN
TYP
MAX
UNITS
DIGITAL DATA OUTPUTS (CMOS MODES: FULL DATA RATE AND DOUBLE DATA RATE)
tD
ENC to Data Delay
CL = 5pF (Note 8)
l
1.1
1.7
3.1
ns
tC
ENC to CLKOUT Delay
CL = 5pF (Note 8)
l
1
1.4
2.6
ns
tSKEW
DATA to CLKOUT Skew
tD – tC (Note 8)
l
0
0.3
0.6
Pipeline Latency
Full Data Rate Mode
Double Data Rate Mode
6
6.5
ns
Cycles
Cycles
DIGITAL DATA OUTPUTS (LVDS MODE)
tD
ENC to Data Delay
CL = 5pF (Note 8)
l
1.1
1.8
3.2
ns
tC
ENC to CLKOUT Delay
CL = 5pF (Note 8)
l
1
1.5
2.7
ns
tSKEW
DATA to CLKOUT Skew
tD – tC (Note 8)
l
0
0.3
0.6
Pipeline Latency
6.5
ns
Cycles
SPI PORT TIMING (Note 8)
tSCK
SCK Period
tS
Write Mode
Readback Mode, CSDO = 20pF, RPULLUP = 2k
l
l
40
250
ns
ns
CS to SCK Setup Time
l
5
ns
tH
SCK to CS Setup Time
l
5
ns
tDS
SDI Setup Time
l
5
ns
tDH
SDI Hold Time
l
5
tDO
SCK Falling to SDO Valid
Readback Mode, CSDO = 20pF, RPULLUP = 2k
l
ns
125
ns
216210f
7
LTC2162/LTC2161/LTC2160
electrical Characteristics
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: All voltage values are with respect to GND with GND and OGND
shorted (unless otherwise noted).
Note 3: When these pin voltages are taken below GND or above VDD, they
will be clamped by internal diodes. This product can handle input currents
of greater than 100mA below GND or above VDD without latchup.
Note 4: When these pin voltages are taken below GND they will be
clamped by internal diodes. When these pin voltages are taken above VDD
they will not be clamped by internal diodes. This product can handle input
currents of greater than 100mA below GND without latchup.
Note 5: VDD = OVDD = 1.8V, fSAMPLE = 65MHz (LTC2162), 40MHz (LTC2161),
or 25MHz (LTC2160), LVDS outputs, differential ENC+/ENC– = 2VP-P sine
wave, input range = 2VP-P with differential drive, unless otherwise noted.
Note 6: Integral nonlinearity is defined as the deviation of a code from a
best fit straight line to the transfer curve. The deviation is measured from
the center of the quantization band.
Note 7: Offset error is the offset voltage measured from –0.5 LSB when
the output code flickers between 0000 0000 0000 0000 and 1111 1111
1111 1111 in 2’s complement output mode.
Note 8: Guaranteed by design, not subject to test.
Note 9: VDD = 1.8V, fSAMPLE = 65MHz (LTC2162), 40MHz (LTC2161), or
25MHz (LTC2160), CMOS outputs, ENC+ = single-ended 1.8V square wave,
ENC– = 0V, input range = 2VP-P with differential drive, 5pF load on each
digital output unless otherwise noted.
Note 10: Recommended operating conditions.
Timing Diagrams
Full-Rate CMOS Output Mode Timing
All Outputs are Single-Ended and Have CMOS Levels
tAP
ANALOG
INPUT
N+4
N+2
N
N+3
tH
tL
N+1
ENC–
ENC+
tD
N–6
D0–D15, OF
CLKOUT +
CLKOUT –
N–5
N–4
N–3
N–2
tC
216210 TD01
216210f
8
LTC2162/LTC2161/LTC2160
timing diagrams
Double Data Rate CMOS Output Mode Timing
All Outputs are Single-Ended and Have CMOS Levels
tAP
ANALOG
INPUT
N+4
N+2
N
N+3
tH
tL
N+1
ENC–
ENC+
tD
D0_1
tD
D0N-6
D1N-6
D0N-5
D1N-5
D0N-4
D1N-4
D0N-3
D1N-3
D14N-6
D15N-6 D14N-5
D15N-5
D14N-4
D15N-4
D14N-3
D15N-3
••
•
D14_15
OFN-6
OF
OFN-5
OFN-3
tC
tC
CLKOUT+
OFN-4
CLKOUT –
216210 TD02
Double Data Rate LVDS Output Mode Timing
All Outputs are Differential and Have LVDS Levels
tAP
ANALOG
INPUT
N+4
N+2
N
N+3
tH
tL
N+1
ENC–
ENC+
D0_1+
D0_1–
tD
tD
D0N-6
D1N-6
D0N-5
D1N-5
D0N-4
D1N-4
D0N-3
D1N-3
D14N-6
D15N-6
D14N-5
D15N-5
D14N-4
D15N-4
D14N-3
D15N-3
••
•
D14_15+
D14_15–
OF+
OF–
CLKOUT+
CLKOUT –
OFN-6
tC
OFN-5
OFN-4
OFN-3
tC
216210 TD03
216210f
9
LTC2162/LTC2161/LTC2160
timing diagrams
SPI Port Timing (Readback Mode)
tDS
tS
tDH
tSCK
tH
CS
SCK
tDO
SDI
SDO
R/W
A6
A5
A4
A3
A2
A1
A0
XX
D7
HIGH IMPEDANCE
XX
D6
XX
D5
XX
D4
XX
D3
XX
D2
XX
XX
D1
D0
SPI Port Timing (Write Mode)
CS
SCK
SDI
SDO
R/W
HIGH IMPEDANCE
A6
A5
A4
A3
A2
A1
A0
D7
D6
D5
D4
D3
D2
D1
D0
216210 TD04
216210f
10
LTC2162/LTC2161/LTC2160
Typical Performance Characteristics
1.0
–20
0.6
DNL ERROR (LSB)
2.0
1.0
0
–1.0
–2.0
–30
0.4
0.2
0
–0.2
–0.4
–3.0
–0.8
–4.0
–1.0
0
16384
32768
49152
OUTPUT CODE
65536
–60
–70
–80
0
16384
32768
49152
OUTPUT CODE
65536
–110
–120
0
–10
–20
–20
–20
–30
–30
–30
–70
–80
AMPLITUDE (dBFS)
0
–10
AMPLITUDE (dBFS)
0
–60
–40
–50
–60
–70
–80
–40
–50
–60
–70
–80
–90
–100
–90
–100
–90
–100
–110
–120
–110
–120
–110
–120
0
20
10
FREQUENCY (MHz)
30
0
20
10
FREQUENCY (MHz)
216210 G04
30
10000
78
9000
77
–20
8000
–30
–110
–120
SNR (dBFS)
COUNT
6000
5000
4000
3000
–90
–100
30
216210 G07
0
32831
74
DIFFERENTIAL
ENCODE
73
71
1000
20
10
FREQUENCY (MHz)
75
72
2000
0
SINGLE-ENDED
ENCODE
76
7000
–40
–80
30
LTC2162: SNR vs Input Frequency,
–1dBFS, 65Msps, 2V Range
LTC2162: Shorted Input Histogram
0
–70
20
10
FREQUENCY (MHz)
216210 G06
–10
–60
0
216210 G05
LTC2162: 64k Point 2-Tone FFT,
fIN = 69MHz, 70MHz, –7dBFS,
65Msps
–50
30
LTC2162: 64k Point FFT,
fIN = 140MHz, –1dBFS, 65Msps
–10
–50
20
10
FREQUENCY (MHz)
216210 G03
LTC2162: 64k Point FFT,
fIN = 70MHz, –1dBFS, 65Msps
–40
0
216210 G02
LTC2162: 64k Point FFT,
fIN = 30MHz, –1dBFS, 65Msps
AMPLITUDE (dBFS)
–40
–50
–90
–100
–0.6
216210 G01
AMPLITUDE (dBFS)
0
LTC2162: 64k Point FFT, fIN = 5MHz
–1dBFS, 65Msps
–10
0.8
3.0
INL ERROR (LSB)
LTC2162: Differential
Non-Linearity (DNL)
AMPLITUDE (dBFS)
4.0
LTC2162: Integral
Non-Linearity (INL)
32837
32843
32849
OUTPUT CODE
32855
216210 G08
70
0
50
100
150
200
250
INPUT FREQUENCY (MHz)
300
216210 G09
216210f
11
LTC2162/LTC2161/LTC2160
Typical Performance Characteristics
LTC2162: 2nd, 3rd Harmonic vs
Input Frequency, –1dBFS, 65Msps,
1V Range
100
95
95
90
3RD
85
80
2ND
75
70
0
50
100
150
200
250
INPUT FREQUENCY (MHz)
85
2ND
80
75
60
0
50
100
150
200
250
INPUT FREQUENCY (MHz)
55
IOVDD (mA)
IVDD (mA)
45
CMOS OUTPUTS
LTC2162: SNR vs SENSE,
fIN = 5MHz, –1dBFS
77
3.5mA LVDS
76
30
1.75mA LVDS
20
1.2V CMOS
0
60
0
20
40
SAMPLE RATE (Msps)
3.0
1.0
0
0.8
–10
0
–1.0
–2.0
0.2
0
–0.2
–0.4
216210 G16
0.9
1
1.1
SENSE PIN (V)
1.2
–1.0
1.3
LTC2161: 64k Point FFT,
fIN = 5MHz, –1dBFS, 40Msps
–40
–50
–60
–70
–80
–90
–100
–0.8
65536
0.8
–30
0.4
–0.6
–3.0
0.7
–20
AMPLITUDE (dBFS)
DNL ERROR (LSB)
1.0
0.6
216210 G15
0.6
2.0
INL ERROR (LSB)
70
60
LTC2161: Differential
Non-Linearity (DNL)
4.0
32768
49152
OUTPUT CODE
73
216210 G14
LTC2161: Integral
Non-Linearity (INL)
16384
74
71
1.8V CMOS
216210 G13
0
75
72
10
35
0
216210 G12
40
–4.0
50
78
40
20
40
SAMPLE RATE (Msps)
60
20
–80 –70 –60 –50 –40 –30 –20 –10
INPUT LEVEL (dBFS)
300
50
0
70
LTC2162: IOVDD vs Sample Rate,
5MHz, –1dBFS Sine Wave Input
3.5mA LVDS
OUTPUTS
dBc
216210 G11
LTC2162: IVDD vs Sample Rate,
5MHz, –1dBFS Sine Wave Input
30
90
80
30
216210 G10
50
100
40
70
300
dBFS
110
3RD
90
65
LTC2162: SFDR vs Input Level,
fIN = 70MHz, 65Msps, 2V Range
120
SNR (dBFS)
65
130
SFDR (dBc AND dBFS)
100
2ND AND 3RD HARMONIC (dBFS)
2ND AND 3RD HARMONIC (dBFS)
LTC2162: 2nd, 3rd Harmonic vs
Input Frequency, –1dBFS, 65Msps,
2V Range
0
16384
32768
49152
OUTPUT CODE
65536
216210 G17
–110
–120
0
5
10
15
FREQUENCY (MHz)
20
216210 G18
216210f
12
LTC2162/LTC2161/LTC2160
Typical Performance Characteristics
0
LTC2161: 64k Point FFT,
fIN = 70MHz, –1dBFS, 40Msps
0
–10
–10
–20
–20
–20
–30
–30
–30
–40
–50
–60
–70
–80
AMPLITUDE (dBFS)
–10
AMPLITUDE (dBFS)
AMPLITUDE (dBFS)
0
LTC2161: 64k Point FFT,
fIN = 30MHz, –1dBFS, 40Msps
–40
–50
–60
–70
–80
–40
–50
–60
–70
–80
–90
–100
–90
–100
–90
–100
–110
–120
–110
–120
–110
–120
0
5
10
15
FREQUENCY (MHz)
20
0
5
10
15
FREQUENCY (MHz)
216210 G19
LTC2161: 64k Point 2-Tone FFT,
fIN = 69MHz, 70MHz, –7dBFS,
40Msps
9000
77
8000
–80
5000
4000
3000
–90
–100
5
10
15
FREQUENCY (MHz)
0
32823
20
32829
216210 G22
95
95
2ND AND 3RD HARMONIC (dBFS)
100
3RD
80
2ND
75
70
65
0
50
32835 32841
OUTPUT CODE
70
32847
100
150
200
250
INPUT FREQUENCY (MHz)
300
216210 G25
0
50
100
150
200
250
INPUT FREQUENCY (MHz)
130
120
85
2ND
80
75
dBFS
100
90
80
dBc
70
60
50
40
70
65
LTC2161: SFDR vs Input Level,
fIN = 70MHz, 40Msps, 2V Range
110
3RD
90
300
216210 G24
LTC2161: 2nd, 3rd Harmonic
vs Input Frequency, –1dBFS,
40Msps, 1V Range
100
85
73
216210 G23
LTC2161: 2nd, 3rd Harmonic
vs Input Frequency, –1dBFS,
40Msps, 2V Range
90
DIFFERENTIAL
ENCODE
74
71
1000
0
75
72
2000
SFDR (dBc AND dBFS)
–110
–120
6000
SNR (dBFS)
COUNT
AMPLITUDE (dBFS)
–70
SINGLE-ENDED
ENCODE
76
7000
–60
20
LTC2161: SNR vs Input Frequency,
–1dBFS, 40Msps, 2V Range
78
–50
10
15
FREQUENCY (MHz)
LTC2161: Shorted Input Histogram
10000
–40
5
216210 G21
0
–30
0
216210 G20
–10
–20
2ND AND 3RD HARMONIC (dBFS)
20
LTC2161: 64k Point FFT,
fIN = 140MHz, –1dBFS, 40Msps
30
0
50
100
150
200
250
INPUT FREQUENCY (MHz)
300
216210 G26
20
–80 –70 –60 –50 –40 –30 –20 –10
INPUT LEVEL (dBFS)
0
216210 G27
216210f
13
LTC2162/LTC2161/LTC2160
Typical Performance Characteristics
LTC2161: IVDD vs Sample Rate,
5MHz, –1dBFS Sine Wave Input
LTC2161: IOVDD vs Sample Rate,
5MHz, –1dBFS Sine Wave Input
50
IOVDD (mA)
3.5mA LVDS
OUTPUTS
35
CMOS OUTPUTS
30
76
30
1.75mA LVDS
20
0
20
20
30
SAMPLE RATE (Msps)
0
40
0
10
20
30
SAMPLE RATE (Msps)
3.0
0
–1.0
–2.0
1.0
0
0.8
–10
0.2
0
–0.2
–0.4
–1.0
65536
–50
–60
–70
–80
0
16384
32768
49152
OUTPUT CODE
–110
–120
65536
LTC2160: 64k Point FFT,
fIN = 70MHz, –1dBFS, 25Msps
0
–10
–20
–20
–20
–30
–30
–30
–80
AMPLITUDE (dBFS)
–10
–70
–40
–50
–60
–70
–80
–70
–80
–110
–120
–110
–120
–110
–120
0
5
FREQUENCY (MHz)
10
216210 G35
LTC2160: 64k Point FFT,
fIN = 140MHz, –1dBFS, 25Msps
–50
–90
–100
216210 G34
10
–60
–90
–100
10
5
FREQUENCY (MHz)
–40
–90
–100
5
FREQUENCY (MHz)
0
216210 G33
–10
AMPLITUDE (dBFS)
AMPLITUDE (dBFS)
0
1.3
–40
216210 G32
LTC2160: 64k Point FFT,
fIN = 30MHz, –1dBFS, 25Msps
–60
1.2
–90
–100
216210 G31
–50
0.9
1
1.1
SENSE PIN (V)
–30
0.4
–0.8
–40
0.8
–20
–0.6
–3.0
32768
49152
OUTPUT CODE
0.7
LTC2160: 64k Point FFT,
fIN = 5MHz, –1dBFS, 25Msps
AMPLITUDE (dBFS)
DNL ERROR (LSB)
INL ERROR (LSB)
1.0
0
0.6
216210 G30
0.6
2.0
0
70
40
LTC2160: Differential
Non-Linearity (DNL)
4.0
16384
73
216210 G29
LTC2160: Integral
Non-Linearity (INL)
0
74
71
1.8V CMOS
216210 G28
–4.0
75
72
10
1.2V CMOS
25
77
3.5mA LVDS
40
40
IVDD (mA)
78
SNR (dBFS)
45
LTC2161: SNR vs SENSE,
fIN = 5MHz, –1dBFS
0
5
FREQUENCY (MHz)
10
216210 G36
216210f
14
LTC2162/LTC2161/LTC2160
Typical Performance Characteristics
LTC2160: 64k Point 2-Tone FFT,
fIN = 69MHz, 70MHz, –7dBFS,
25Msps
LTC2160: Shorted Input
Histogram
0
10000
78
–10
9000
77
–20
8000
–30
–60
–70
–80
5000
4000
3000
–90
–100
5
FREQUENCY (MHz)
0
32836
10
32842
32848
32854
OUTPUT CODE
100
95
95
2ND AND 3RD HARMONIC (dBFS)
2ND AND 3RD HARMONIC (dBFS)
100
80
2ND
75
70
65
0
50
100
150
200
250
INPUT FREQUENCY (MHz)
LTC2160: SFDR vs Input Level,
fIN = 70MHz, 25Msps, 2V Range
110
3RD
85
2ND
80
75
0
50
100
150
200
250
INPUT FREQUENCY (MHz)
78
76
SNR (dBFS)
30
1.75mA LVDS
20
1.2V CMOS
216210 G43
75
74
73
72
10
0
LTC2160: SNR vs SENSE,
fIN = 5MHz, –1dBFS
77
22
25
0
216210 G42
40
IOVDD (mA)
IVDD (mA)
50
LTC2160: IOVDD vs Sample Rate,
5MHz, –1dBFS Sine Wave Input
3.5mA LVDS
OUTPUTS
10
15
20
SAMPLE RATE (Msps)
60
20
–80 –70 –60 –50 –40 –30 –20 –10
INPUT LEVEL (dBFS)
300
3.5mA LVDS
5
dBc
70
30
50
0
90
80
216210 G41
30
18
dBFS
100
40
70
LTC2160: IVDD vs Sample Rate,
5MHz, –1dBFS Wine Wave Input
300
120
90
65
300
CMOS OUTPUTS
100
150
200
250
INPUT FREQUENCY (MHz)
130
216210 G40
26
50
216210 G39
LTC2160: 2nd, 3rd Harmonic
vs Input Frequency, –1dBFS,
25Msps, 1V Range
3RD
0
216210 G38
LTC2160: 2nd, 3rd Harmonic
vs Input Frequency, –1dBFS,
25Msps, 2V Range
90
DIFFERENTIAL
ENCODE
73
70
32860
216210 G37
85
74
71
1000
0
75
72
2000
SFDR (dBc AND dBFS)
–110
–120
6000
SNR (dBFS)
–50
SINGLE-ENDED
ENCODE
76
7000
–40
COUNT
AMPLITUDE (dBFS)
LTC2160: SNR vs Input Frequency,
–1dBFS, 25Msps, 2V Range
0
5
71
1.8V CMOS
10
15
20
SAMPLE RATE (Msps)
25
216210 G44
70
0.6
0.7
0.8
0.9
1
1.1
SENSE PIN (V)
1.2
1.3
216210 G45
216210f
15
LTC2162/LTC2161/LTC2160
Pin Functions
(Pins that are the Same for All Digital Output Modes)
VCM (Pin 1): Common Mode Bias Output. Nominally
equal to VDD /2. VCM should be used to bias the common
mode of the analog inputs. Bypass to ground with a 0.1µF
ceramic capacitor.
AIN+ (Pin 2): Positive Differential Analog Input.
AIN– (Pin 3): Negative Differential Analog Input.
GND (Pins 4, 10, 11, 14, 20, 43, Exposed Pad Pin 49):
ADC Power Ground. The exposed pad must be soldered
to the PCB ground.
REFH (Pins 5, 7): ADC High Reference. See the Applications Information section for recommended bypassing
circuits for REFH and REFL.
REFL (Pins 6, 8): ADC Low Reference. See the Applications
Information section for recommended bypassing circuits
for REFH and REFL.
PAR/SER (Pin 9): Programming Mode Selection Pin. Connect to ground to enable the serial programming mode.
CS, SCK, SDI, SDO become a serial interface that control
the A/D operating modes. Connect to VDD to enable the
parallel programming mode where CS, SCK, SDI, SDO
become parallel logic inputs that control a reduced set of
the A/D operating modes. PAR/SER should be connected
directly to ground or VDD and not be driven by a logic signal.
VDD (Pins 12, 13, 47, 48): Analog Power Supply, 1.7V
to 1.9V. Bypass to ground with 0.1µF ceramic capacitors.
Adjacent pins can share a bypass capacitor.
ENC+ (Pin 15): Encode Input. Conversion starts on the
rising edge.
ENC– (Pin 16): Encode Complement Input. Conversion
starts on the falling edge. Tie to GND for single-ended
encode mode.
CS (Pin 17): Serial Interface Chip Select Input. In serial
programming mode (PAR/SER = 0V), CS is the serial interface chip select input. When CS is low, SCK is enabled
for shifting data on SDI into the mode control registers.
In the parallel programming mode (PAR/SER = VDD),
CS controls the clock duty cycle stabilizer (see Table 2).
CS can be driven with 1.8V to 3.3V logic.
SCK (Pin 18): Serial Interface Clock Input. In serial
programming mode, (PAR/SER = 0V), SCK is the serial
interface clock input. In the parallel programming mode
(PAR/SER = VDD), SCK controls the digital output mode
(see Table 2). SCK can be driven with 1.8V to 3.3V logic.
SDI (Pin 19): Serial Interface Data Input. In serial programming mode, (PAR/SER = 0V), SDI is the serial interface
data input. Data on SDI is clocked into the mode control
registers on the rising edge of SCK. In the parallel programming mode (PAR/SER = VDD), SDI can be used together
with SDO to power down the part (Table 2). SDI can be
driven with 1.8V to 3.3V logic.
OGND (Pin 31): Output Driver Ground. Must be shorted
to the ground plane by a very low inductance path. Use
multiple vias close to the pin.
OVDD (Pin 32): Output Driver Supply. Bypass to ground
with a 0.1µF ceramic capacitor.
SDO (Pin 44): Serial Interface Data Output. In serial programming mode, (PAR/SER = 0V), SDO is the optional
serial interface data output. Data on SDO is read back from
the mode control registers and can be latched on the falling edge of SCK. SDO is an open-drain NMOS output that
requires an external 2k pull-up resistor to 1.8V – 3.3V. If
read back from the mode control registers is not needed,
the pull-up resistor is not necessary and SDO can be left
unconnected. In the parallel programming mode (PAR/SER
= VDD), SDO can be used together with SDI to power down
the part (Table 2). When used as an input, SDO can be
driven with 1.8V to 3.3V logic through a 1k series resistor.
VREF (Pin 45): Reference Voltage Output. Bypass to
ground with a 2.2µF ceramic capacitor. The output voltage
is nominally 1.25V.
SENSE (Pin 46): Reference Programming Pin. Connecting
SENSE to VDD selects the internal reference and a ±1V input
range. Connecting SENSE to ground selects the internal
reference and a ±0.5V input range. An external reference
between 0.625V and 1.3V applied to SENSE selects an
input range of ±0.8 • VSENSE.
216210f
16
LTC2162/LTC2161/LTC2160
pin functions
FULL RATE CMOS OUTPUT MODE
DOUBLE DATA RATE LVDS OUTPUT MODE
All Pins Below Have CMOS Output Levels (OGND to
OVDD)
All Pins Below Have LVDS Output Levels. The Output
Current Level is Programmable. There is an Optional
Internal 100Ω Termination Resistor Between the Pins
of Each LVDS Output Pair.
D0 to D15 (Pins 21-28, 33-40): Digital Outputs. D15 is
the MSB.
CLKOUT– (Pin 29): Inverted version of CLKOUT+.
CLKOUT+ (Pin 30): Data Output Clock. The digital outputs
normally transition at the same time as the falling edge
of CLKOUT+. The phase of CLKOUT+ can also be delayed
relative to the digital outputs by programming the mode
control registers.
DNC (Pin 41): Do not connect this pin.
OF (Pin 42): Overflow/Underflow Digital Output. OF is high
when an overflow or underflow has occurred.
DOUBLE DATA RATE CMOS OUTPUT MODE
All Pins Below Have CMOS Output Levels (OGND to
OVDD)
D0_1–/D0_1+ to D14_15–/D14_15+ (Pins 21/22, 23/24,
25/26, 27/28, 33/34, 35/36, 37/38, 39/40): Double Data
Rate Digital Outputs. Two data bits are multiplexed onto
each differential output pair. The even data bits (D0, D2,
D4, D6, D8, D10, D12, D14) appear when CLKOUT+ is low.
The odd data bits (D1, D3, D5, D7, D9, D11, D13, D15)
appear when CLKOUT+ is high.
CLKOUT–/CLKOUT+ (Pins 39/40): Data Output Clock.
The digital outputs normally transition at the same time
as the falling and rising edges of CLKOUT+. The phase of
CLKOUT+ can also be delayed relative to the digital outputs
by programming the mode control registers.
OF–/OF+ (Pins 41/42): Overflow/Underflow Digital Output.
OF+ is high when an overflow or underflow has occurred.
D0_1 to D14_15 (Pins 22, 24, 26, 28, 34, 36, 38, 40):
Double Data Rate Digital Outputs. Two data bits are multiplexed onto each output pin. The even data bits (D0,
D2, D4, D6, D8, D10, D12, D14) appear when CLKOUT+
is low. The odd data bits (D1, D3, D5, D7, D9, D11, D13,
D15) appear when CLKOUT+ is high.
DNC (Pins 21, 23, 25, 27, 33, 35, 37, 39, 41): Do not
connect these pins.
CLKOUT– (Pin 29): Inverted version of CLKOUT+.
CLKOUT+ (Pin 30): Data Output Clock. The digital outputs
normally transition at the same time as the falling and rising edges of CLKOUT+. The phase of CLKOUT+ can also
be delayed relative to the digital outputs by programming
the mode control registers.
OF (Pin 42): Overflow/Underflow Digital Output. OF is high
when an overflow or underflow has occurred.
216210f
17
LTC2162/LTC2161/LTC2160
Functional Block Diagram
VDD
OVDD
ANALOG
INPUT
16-BIT
ADC CORE
S/H
OF
CORRECTION
LOGIC
•
•
•
OUTPUT
DRIVERS
VREF
2.2µF
1.25V
REFERENCE
D15
D0
CLKOUT +
CLKOUT –
RANGE
SELECT
SENSE
VCM
REFH
REF
BUF
REFL
DIFF
REF
AMP
VDD/2
OGND
INTERNAL CLOCK SIGNALS
CLOCK/DUTY
CYCLE
CONTROL
MODE
CONTROL
REGISTERS
0.1µF
REFH
GND
0.1µF
2.2µF
2162 BD
REFL
+
ENC
ENC–
PAR/SER CS SCK SDI SDO
0.1µF
Figure 1. Functional Block Diagram
Applications Information
CONVERTER OPERATION
ANALOG INPUT
The LTC2162/LTC2161/LTC2160 are low power, 16-bit,
65Msps/40Msps/25Msps A/D converters that are powered
by a single 1.8V supply. The analog inputs should be driven
differentially. The encode input can be driven differentially
or single-ended for lower power consumption. The digital
outputs can be CMOS, double data rate CMOS (to halve
the number of output lines), or double data rate LVDS
(to reduce digital noise in the system). Many additional
features can be chosen by programming the mode control
registers through a serial SPI port.
The analog inputs are differential CMOS sample-and-hold
circuits (Figure 2). The inputs should be driven differentially
around a common mode voltage set by the VCM output
pin, which is nominally VDD/2. For the 2V input range,
the inputs should swing from VCM – 0.5V to VCM + 0.5V.
There should be 180° phase difference between the inputs.
216210f
18
LTC2162/LTC2161/LTC2160
Applications Information
Transformer Coupled Circuits
LTC2162
VDD
AIN+
RON
15Ω
10Ω
CPARASITIC
1.8pF
VDD
AIN–
CSAMPLE
5pF
RON
15Ω
10Ω
CSAMPLE
5pF
CPARASITIC
1.8pF
Figure 3 shows the analog input being driven by an RF
transformer with a center-tapped secondary. The center
tap is biased with VCM, setting the A/D input at its optimal
DC level. At higher input frequencies a transmission line
balun transformer (Figures 4 through 6) has better balance, resulting in lower A/D distortion.
Amplifier Circuits
VDD
Figure 7 shows the analog input being driven by a high
speed differential amplifier. The output of the amplifier is
AC coupled to the A/D so the amplifier’s output common
mode voltage can be optimally set to minimize distortion.
1.2V
10k
ENC+
ENC–
10k
1.2V
216210 F02
At very high frequencies an RF gain block will often have
lower distortion than a differential amplifier. If the gain
block is single-ended, then a transformer circuit (Figures 4
through 6) should convert the signal to differential before
driving the A/D.
Figure 2. Equivalent Input Circuit
50Ω
0.1µF
Single-Ended Input
For applications less sensitive to harmonic distortion, the
AIN+ input can be driven single-ended with a 1VP-P signal
centered around VCM. The AIN– input should be connected
to VCM and the VCM bypass capacitor should be increased
to 2.2µF. With a single-ended input the harmonic distortion
and INL will degrade, but the noise and DNL will remain
unchanged.
INPUT DRIVE CIRCUITS
VCM
0.1µF
ANALOG
INPUT
T1
1:1
AIN+
25Ω
25Ω
LTC2162
0.1µF
12pF
25Ω
25Ω
T1: MA/COM MABAES0060 RESISTORS,
CAPACITORS ARE 0402 PACKAGE SIZE
AIN–
216210 F03
Figure 3. Analog Input Circuit Using a Transformer.
Recommended for Input Frequencies from 5MHz to 70MHz
Input filtering
If possible, there should be an RC lowpass filter right at
the analog inputs. This lowpass filter isolates the drive
circuitry from the A/D sample-and-hold switching, and also
limits wideband noise from the drive circuitry. Figure 3
shows an example of an input RC filter. The RC component
values should be chosen based on the application’s input
frequency.
216210f
19
LTC2162/LTC2161/LTC2160
applications information
50Ω
VCM
0.1µF
0.1µF
ANALOG
INPUT
T1
AIN+
12Ω
T2
25Ω
LTC2162
0.1µF
8.2pF
0.1µF
25Ω
AIN–
12Ω
216210 F04
T1: MA/COM MABA-007159-000000
T2: COILCRAFT WBC1-1TL
RESISTORS, CAPACITORS ARE 0402 PACKAGE SIZE
Figure 4. Recommended Front End Circuit for
Input Frequencies from 5MHz to 150MHz
50Ω
VCM
0.1µF
0.1µF
ANALOG
INPUT
AIN+
T2
T1
25Ω
LTC2162
0.1µF
1.8pF
0.1µF
25Ω
AIN–
216210 F05
T1: MA/COM MABA-007159-000000
T2: COILCRAFT WBC1-1TL
RESISTORS, CAPACITORS ARE 0402 PACKAGE SIZE
Figure 5. Recommended Front End Circuit for
Input Frequencies from 150MHz to 250MHz
50Ω
VCM
VCM
HIGH SPEED
DIFFERENTIAL
0.1µF
AMPLIFIER
0.1µF
0.1µF
ANALOG
INPUT
4.7nH
T1
0.1µF
LTC2162
0.1µF
25Ω
25Ω
AIN+
4.7nH
Figure 6. Recommended Front End Circuit for
Input Frequencies Above 250MHz
216210 F06
200Ω
25Ω
+
–
AIN–
T1: MA/COM ETC1-1-13
RESISTORS, CAPACITORS
ARE 0402 PACKAGE SIZE
ANALOG
INPUT
200Ω
0.1µF
AIN+
12pF
0.1µF
25Ω
LTC2162
AIN–
12pF
216210 F07
Figure 7. Front End Circuit Using a
High Speed Differential Amplifier
216210f
20
LTC2162/LTC2161/LTC2160
Applications Information
Reference
The LTC2162/LTC2161/LTC2160 has an internal 1.25V
voltage reference. For a 2V input range using the internal
reference, connect SENSE to VDD. For a 1V input range
using the internal reference, connect SENSE to ground.
For a 2V input range with an external reference, apply a
1.25V reference voltage to SENSE (Figure 9).
The input range can be adjusted by applying a voltage to
SENSE that is between 0.625V and 1.30V. The input range
will then be 1.6 • VSENSE.
The VREF, REFH and REFL pins should be bypassed as
shown in Figure 8a. A low inductance 2.2µF interdigitated
capacitor is recommended for the bypass between REFH
and REFL. This type of capacitor is available at a low cost
from multiple suppliers.
Alternatively, C1 can be replaced by a standard 2.2µF
capacitor between REFH and REFL. The capacitor should
be as close to the pins as possible (not on the back side
of the circuit board).
REFH
C3
0.1µF
LTC2162
REFL
C1
2.2µF
REFH
C2
0.1µF
REFL
CAPACITORS ARE 0402 PACKAGE SIZE
216210 F08b
Figure 8b. Alternative REFH/REFL Bypass Circuit
Figures 8c and 8d show the recommended circuit board
layout for the REFH/REFL bypass capacitors. Note that in
Figure 8c, every pin of the interdigitated capacitor (C1)
is connected since the pins are not internally connected
in some vendors’ capacitors. In Figure 8d, the REFH and
REFL pins are connected by short jumpers in an internal
layer. To minimize the inductance of these jumpers they
can be placed in a small hole in the GND plane on the
second board layer.
LTC2162
VREF
1.25V
5Ω
2.2µF
1.25V BANDGAP
REFERENCE
0.625V
TIE TO VDD FOR 2V RANGE;
TIE TO GND FOR 1V RANGE;
RANGE = 1.6 • VSENSE FOR
0.625V < VSENSE < 1.300V
Figure 8c. Recommended Layout for the REFH/REFL
Bypass Circuit in Figure 8a
RANGE
DETECT
AND
CONTROL
SENSE
BUFFER
INTERNAL ADC
HIGH REFERENCE
C2
0.1µF
–
+
REFH
+
–
REFL
–
+
REFH
+
–
REFL
C1
C3
0.1µF
Figure 8d. Recommended Layout for the REFH/REFL
Bypass Circuit in Figure 8b
0.8x
DIFF AMP
VREF
INTERNAL ADC
LOW REFERENCE
C1: 2.2µF LOW INDUCTANCE
INTERDIGITATED CAPACITOR
TDK CLLE1AX7S0G225M
MURATA LLA219C70G225M
AVX W2L14Z225M
OR EQUIVALENT
Figure 8a. Reference Circuit
2.2µF
216210 F08
1.25V
EXTERNAL
REFERENCE
LTC2162
SENSE
1µF
216210 F09
Figure 9. Using an External 1.25V Reference
216210f
21
LTC2162/LTC2161/LTC2160
applications information
Encode Input
The signal quality of the encode inputs strongly affects
the A/D noise performance. The encode inputs should
be treated as analog signals—do not route them next to
digital traces on the circuit board. There are two modes
of operation for the encode inputs: the differential encode
mode (Figure 10), and the single-ended encode mode
(Figure 11).
LTC2162
VDD
DIFFERENTIAL
COMPARATOR
VDD
0.1µF
ENC+
T1
50Ω
0.1µF
ENC–
216210 F12
T1 = MA/COM ETC1-1-13
RESISTORS AND CAPACITORS
ARE 0402 PACKAGE SIZE
Figure 12. Sinusoidal Encode Drive
15k
PECL OR
LVDS
CLOCK
ENC–
100Ω
50Ω
0.1µF
0.1µF
ENC+
LTC2162
ENC+
LTC2162
0.1µF
30k
ENC–
216210 F13
216210 F10
Figure 10. Equivalent Encode Input
Circuit for Differential Encode Mode
LTC2162
1.8V TO 3.3V
0V
ENC+
ENC–
30k
CMOS LOGIC
BUFFER
216210 F11
Figure 11. Equivalent Encode Input
Circuit for Single-Ended Encode Mode.
The differential encode mode is recommended for sinusoidal, PECL, or LVDS encode inputs (Figures 12, 13).
The encode inputs are internally biased to 1.2V through
10kΩ equivalent resistance. The encode inputs can be
taken above VDD (up to 3.6V), and the common mode
range is from 1.1V to 1.6V. In the differential encode
mode, ENC– should stay at least 200mV above ground to
avoid falsely triggering the single-ended encode mode.
For good jitter performance ENC+ and ENC– should have
fast rise and fall times.
The single ended encode mode should be used with
CMOS encode inputs. To select this mode, ENC– is connected to ground and ENC+ is driven with a square wave
Figure 13. PECL or LVDS Encode Drive
encode input. ENC+ can be taken above VDD (up to 3.6V)
enabling 1.8V to 3.3V CMOS logic levels to be used. The
ENC+ threshold is 0.9V. For good jitter performance ENC+
should have fast rise and fall times.
If the encode signal is turned off or drops below approximately 500kHz, the A/D enters nap mode.
Clock Duty Cycle Stabilizer
For good performance the encode signal should have a
50%(±5%) duty cycle. If the optional clock duty cycle
stabilizer circuit is enabled, the encode duty cycle can
vary from 30% to 70% and the duty cycle stabilizer will
maintain a constant 50% internal duty cycle. If the encode
signal changes frequency, the duty cycle stabilizer circuit
requires one hundred clock cycles to lock onto the input
clock. The duty cycle stabilizer is enabled by mode control
register A2 (serial programming mode), or by CS (parallel
programming mode).
For applications where the sample rate needs to be changed
quickly, the clock duty cycle stabilizer can be disabled. If
the duty cycle stabilizer is disabled, care should be taken
to make the sampling clock have a 50%(±5%) duty cycle.
The duty cycle stabilizer should not be used below 5Msps.
216210f
22
LTC2162/LTC2161/LTC2160
Applications Information
DIGITAL OUTPUTS
Double Data Rate LVDS Mode
Digital Output Modes
In double data rate LVDS mode, two data bits are multiplexed and output on each differential output pair. There are
eight LVDS output pairs (D0_1+/D0_1– through D14_15+/
D14_15–) for the digital output data. Overflow (OF+/OF–)
and the data output clock (CLKOUT+/CLKOUT–) each have
an LVDS output pair.
The LTC2162/LTC2161/LTC2160 can operate in three digital
output modes: full rate CMOS, double data rate CMOS (to
halve the number of output lines), or double data rate LVDS
(to reduce digital noise in the system.) The output mode
is set by mode control register A3 (serial programming
mode), or by SCK (parallel programming mode). Note that
double data rate CMOS cannot be selected in the parallel
programming mode.
Full Rate CMOS Mode
In full rate CMOS mode the data outputs (D0 to D15),
overflow (OF), and the data output clocks (CLKOUT+,
CLKOUT–) have CMOS output levels. The outputs are
powered by OVDD and OGND which are isolated from the
A/D core power and ground. OVDD can range from 1.1V
to 1.9V, allowing 1.2V through 1.8V CMOS logic outputs.
For good performance, the digital outputs should drive
minimal capacitive loads. If the load capacitance is larger
than 10pF, a digital buffer should be used.
Double Data Rate CMOS Mode
In double data rate CMOS mode, two data bits are multiplexed and output on each data pin. This reduces the
number of digital lines by eight, simplifying board routing
and reducing the number of input pins needed to receive
the data. The data outputs (D0_1, D2_3, D4_5, D6_7, D8_9,
D10_11, D12_13, D14_15), overflow (OF), and the data
output clocks (CLKOUT+, CLKOUT–) have CMOS output
levels. The outputs are powered by OVDD and OGND which
are isolated from the A/D core power and ground. OVDD
can range from 1.1V to 1.9V, allowing 1.2V through 1.8V
CMOS logic outputs.
For good performance, the digital outputs should drive
minimal capacitive loads. If the load capacitance is larger
than 10pF, a digital buffer should be used.
By default the outputs are standard LVDS levels: 3.5mA
output current and a 1.25V output common mode voltage. An external 100Ω differential termination resistor
is required for each LVDS output pair. The termination
resistors should be located as close as possible to the
LVDS receiver.
The outputs are powered by OVDD and OGND which are
isolated from the A/D core power and ground. In LVDS
mode, OVDD must be 1.8V.
Programmable LVDS Output Current
In LVDS mode, the default output driver current is 3.5mA.
This current can be adjusted by serially programming mode
control register A3. Available current levels are 1.75mA,
2.1mA, 2.5mA, 3mA, 3.5mA, 4mA and 4.5mA.
Optional LVDS Driver Internal Termination
In most cases using just an external 100Ω termination
resistor will give excellent LVDS signal integrity. In addition, an optional internal 100Ω termination resistor can
be enabled by serially programming mode control register
A3. The internal termination helps absorb any reflections
caused by imperfect termination at the receiver. When the
internal termination is enabled, the output driver current
is doubled to maintain the same output voltage swing.
Overflow Bit
The overflow output bit outputs a logic high when the
analog input is either overranged or underranged. The
overflow bit has the same pipeline latency as the data bits.
216210f
23
LTC2162/LTC2161/LTC2160
applications information
Phase-Shifting the Output Clock
In full rate CMOS mode the data output bits normally
change at the same time as the falling edge of CLKOUT +,
so the rising edge of CLKOUT+ can be used to latch the
output data. In double data rate CMOS and LVDS modes
the data output bits normally change at the same time as
the falling and rising edges of CLKOUT+. To allow adequate
setup and hold time when latching the data, the CLKOUT+
signal may need to be phase-shifted relative to the data
output bits. Most FPGAs have this feature; this is generally
the best place to adjust the timing.
The LTC2162/LTC2161/LTC2160 can also phase-shift the
CLKOUT+/CLKOUT– signals by serially programming mode
control register A2. The output clock can be shifted by 0°,
45°, 90°, or 135°. To use the phase-shifting feature the
clock duty cycle stabilizer must be turned on. Another
control register bit can invert the polarity of CLKOUT+ and
CLKOUT–, independently of the phase-shift. The combination of these two features enables phase-shifts of 45° up
to 315° (Figure 14).
ENC+
D0-D15, OF
MODE CONTROL BITS
PHASE
SHIFT
CLKINV
CLKPHASE1
CLKPHASE0
0°
0
0
0
45°
0
0
1
90°
0
1
0
135°
0
1
1
180°
1
0
0
225°
1
0
1
270°
1
1
0
315°
1
1
1
CLKOUT+
216210 F14
Figure 14. Phase-Shifting CLKOUT
Table 1. Output Codes vs Input Voltage
AIN+ – AIN–
(2V RANGE)
OF
D15 – D0
(OFFSET BINARY)
D15 – D0
(2’S COMPLEMENT)
>1.000000V
+0.999970V
+0.999939V
1
0
0
1111 1111 1111 1111
1111 1111 1111 1111
1111 1111 1111 1110
0111 1111 1111 1111
0111 1111 1111 1111
0111 1111 1111 1110
+0.000030V
+0.000000V
–0.000030V
–0.000061V
0
0
0
0
1000
1000
0111
0111
0000
0000
1111
1111
–0.999939V
–1.000000V
< –1.000000V
0
0
1
0000 0000 0000 0001
0000 0000 0000 0000
0000 0000 0000 0000
0000
0000
1111
1111
0000
0000
1111
1111
0001
0000
1111
1110
0000
0000
1111
1111
0000
0000
1111
1111
0001
0000
1111
1110
1000 0000 0000 0001
1000 0000 0000 0000
1000 0000 0000 0000
216210f
24
LTC2162/LTC2161/LTC2160
Applications Information
DATA FORMAT
PC BOARD
Table 1 shows the relationship between the analog input
voltage, the digital data output bits and the overflow bit.
By default the output data format is offset binary. The 2’s
complement format can be selected by serially programming mode control register A4.
Digital Output Randomizer
The digital output is randomized by applying an exclusiveOR logic operation between the LSB and all other data
output bits. To decode, the reverse operation is applied
—an exclusive-OR operation is applied between the LSB
and all other bits. The LSB, OF and CLKOUT outputs are
not affected. The output randomizer is enabled by serially
programming mode control register A4.
CLKOUT
CLKOUT
OF
OF
D15
D15/D0
D14
RANDOMIZER
ON
D1
D0
OF
D15/D0
D15
D14/D0
Interference from the A/D digital outputs is sometimes
unavoidable. Digital interference may be from capacitive or
inductive coupling or coupling through the ground plane.
Even a tiny coupling factor can cause unwanted tones
in the ADC output spectrum. By randomizing the digital
output before it is transmitted off chip, these unwanted
tones can be randomized which reduces the unwanted
tone amplitude.
D2
CLKOUT FPGA
•
•
•
D14/D0
D2/D0
D1/D0
D0
216210 F15
Figure 15. Functional Equivalent of Digital Output Randomizer
LTC2162
D2/D0
•
•
•
D14
D2
D1/D0
D1
D0
D0
216210 F16
Figure 16. Unrandomizing a Randomized Digital Output Signal
Alternate Bit Polarity
Another feature that reduces digital feedback on the circuit
board is the alternate bit polarity mode. When this mode is
enabled, all of the odd bits (D1, D3, D5, D7, D9, D11, D13,
D15) are inverted before the output buffers. The even bits
(D0, D2, D4, D6, D8, D10, D12, D14), OF and CLKOUT are
not affected. This can reduce digital currents in the circuit
board ground plane and reduce digital noise, particularly
for very small analog input signals.
When there is a very small signal at the input of the A/D
that is centered around mid-scale, the digital outputs toggle
between mostly 1’s and mostly 0’s. This simultaneous
switching of most of the bits will cause large currents in the
ground plane. By inverting every other bit, the alternate bit
polarity mode makes half of the bits transition high while
half of the bits transition low. This cancels current flow in
the ground plane, reducing the digital noise.
The digital output is decoded at the receiver by inverting
the odd bits (D1, D3, D5, D7, D9, D11, D13, D15.) The
alternate bit polarity mode is independent of the digital
output randomizer—either, both or neither function can
be on at the same time. The alternate bit polarity mode is
enabled by serially programming mode control register A4.
216210f
25
LTC2162/LTC2161/LTC2160
applications information
Digital Output Test Patterns
To allow in-circuit testing of the digital interface to the
A/D, there are several test modes that force the A/D data
outputs (OF, D15 to D0) to known values:
All 1s: all outputs are 1
All 0s: all outputs are 0
Alternating: outputs change from all 1s to all 0s on
alternating samples.
Checkerboard: outputs change from
10101010101010101 to 01010101010101010
on alternating samples.
The digital output test patterns are enabled by serially
programming mode control register A4. When enabled,
the test patterns override all other formatting modes: 2’s
complement, randomizer, alternate bit polarity.
Output Disable
The digital outputs may be disabled by serially programming mode control register A3. All digital outputs including OF and CLKOUT are disabled. The high-impedance
disabled state is intended for in-circuit testing or long
periods of inactivity—it is too slow to multiplex a data
bus between multiple converters at full speed. When the
outputs are disabled the ADC should be put into either
sleep or nap mode.
Sleep and Nap Modes
The A/D may be placed in sleep or nap modes to conserve
power. In sleep mode the entire device is powered down,
resulting in 1mW power consumption. The amount of
time required to recover from sleep mode depends on
the size of the bypass capacitors on VREF, REFH, and
REFL. For the suggested values in Figure 8, the A/D will
stabilize after 2ms.
In nap mode the A/D core is powered down while the internal
reference circuits stay active, allowing faster wake-up than
from sleep mode. Recovering from nap mode requires at
least 100 clock cycles. If the application demands very
accurate DC settling then an additional 50µs should be
allowed so the on-chip references can settle from the
slight temperature shift caused by the change in supply
current as the A/D leaves nap mode.
Sleep mode and nap mode are enabled by mode control
register A1 (serial programming mode), or by SDI and
SDO (parallel programming mode).
DEVICE PROGRAMMING MODES
The operating modes of the LTC2162/LTC2161/LTC2160
can be programmed by either a parallel interface or a
simple serial interface. The serial interface has more flexibility and can program all available modes. The parallel
interface is more limited and can only program some of
the more commonly used modes.
Parallel Programming Mode
To use the parallel programming mode, PAR/SER should
be tied to VDD. The CS, SCK, SDI and SDO pins are binary
logic inputs that set certain operating modes. These pins
can be tied to VDD or ground, or driven by 1.8V, 2.5V, or
3.3V CMOS logic. When used as an input, SDO should be
driven through a 1kΩ series resistor. Table 2 shows the
modes set by CS, SCK, SDI and SDO.
Table 2. Parallel Programming Mode Control Bits (PAR/SER = VDD)
PIN
DESCRIPTION
CS
Clock Duty Cycle Stabilizer Control Bit
0 = Clock Duty Cycle Stabilizer Off
1 = Clock Duty Cycle Stabilizer On
SCK
Digital Output Mode Control Bit
0 = Full Rate CMOS Output Mode
1 = Double Data Rate LVDS Output Mode
(3.5mA LVDS Current, Internal Termination Off)
SDI/SDO
Power-Down Control Bits
00 =Normal Operation
01 =Not Used
10 =Nap Mode
11 =Sleep Mode (Entire Device Powered Down)
216210f
26
LTC2162/LTC2161/LTC2160
Applications Information
Serial Programming Mode
To use the serial programming mode, PAR/SER should be
tied to ground. The CS, SCK, SDI and SDO pins become a
serial interface that program the A/D mode control registers.
Data is written to a register with a 16-bit serial word. Data
can also be read back from a register to verify its contents.
Serial data transfer starts when CS is taken low. The data
on the SDI pin is latched at the first 16 rising edges of
SCK. Any SCK rising edges after the first 16 are ignored.
The data transfer ends when CS is taken high again.
The first bit of the 16-bit input word is the R/W bit. The
next seven bits are the address of the register (A6:A0).
The final eight bits are the register data (D7:D0).
If the R/W bit is low, the serial data (D7:D0) will be written to the register set by the address bits (A6:A0). If the
R/W bit is high, data in the register set by the address bits
(A6:A0) will be read back on the SDO pin (see the Timing
Diagrams). During a read back command the register is
not updated and data on SDI is ignored.
The SDO pin is an open drain output that pulls to ground
with a 200Ω impedance. If register data is read back
through SDO, an external 2k pull-up resistor is required. If
serial data is only written and read back is not needed, then
SDO can be left floating and no pull-up resistor is needed.
Table 3 shows a map of the mode control registers.
Software Reset
If serial programming is used, the mode control registers
should be programmed as soon as possible after the power
supplies turn on and are stable. The first serial command
must be a software reset which will reset all register data
bits to logic 0. To perform a software reset, bit D7 in the
reset register is written with a logic 1. After the reset SPI
write command is complete, bit D7 is automatically set
back to zero.
Table 3. Serial Programming Mode Register Map (PAR/SER = GND)
REGISTER A0: RESET REGISTER (ADDRESS 00h)
D7
D6
D5
D4
D3
D2
D1
D0
RESET
X
X
X
X
X
X
X
RESET
Bits 7
Software Reset Bit
0 = Not Used
1 = Software Reset. All Mode Control Registers are reset to 00h. The ADC is momentarily placed in sleep mode.
This bit is automatically set back to zero at the end of the SPI write command.
The Reset register is write-only. Data read back from the reset register will be random.
Bits 6-0
Unused, Don’t Care Bits
REGISTER A1: POWER DOWN REGISTER (ADDRESS 01h)
D7
D6
D5
D4
D3
D2
D1
D0
X
X
X
X
X
X
PWROFF1
PWROFF0
Bits 7-2
Unused, Don’t Care Bits
Bits 1-0
PWROFF1: PWROFF0
Power Down Control Bits
00 = Normal Operation
01 = Not Used
10 = Nap Mode
11 = Sleep Mode
216210f
27
LTC2162/LTC2161/LTC2160
applications information
REGISTER A2: TIMING REGISTER (ADDRESS 02h)
D7
D6
D5
D4
D3
D2
D1
D0
X
X
X
X
CLKINV
CLKPHASE1
CLKPHASE0
DCS
Bits 7-4
Unused, Don’t Care Bits
Bit 3
CLKINV
Output Clock Invert Bit
0 = Normal CLKOUT Polarity (as shown in the Timing Diagrams)
1 = Inverted CLKOUT Polarity
CLKPHASE1: CLKPHASE0
Bits 2-1
Output Clock Phase Delay Bits
00 = No CLKOUT Delay (as shown in the Timing Diagrams)
01 = CLKOUT+/CLKOUT– Delayed by 45° (Clock Period × 1/8)
10 = CLKOUT+/CLKOUT– Delayed by 90° (Clock Period × 1/4)
11 = CLKOUT+/CLKOUT– Delayed by 135° (Clock Period × 3/8)
Note: If the CLKOUT phase delay feature is used, the clock duty cycle stabilizer must also be turned on.
DCS
Bit 0
Clock Duty Cycle Stabilizer Bit
0 = Clock Duty Cycle Stabilizer Off
1 = Clock Duty Cycle Stabilizer On
REGISTER A3: OUTPUT MODE REGISTER (ADDRESS 03h)
D7
D6
D5
D4
D3
D2
D1
D0
X
ILVDS2
ILVDS1
ILVDS0
TERMON
OUTOFF
OUTMODE1
OUTMODE0
Bit 7
Unused, Don’t Care Bit
Bits 6-4
ILVDS2: ILVDS0
LVDS Output Current Bits
000 = 3.5mA LVDS Output Driver Current
001 = 4.0mA LVDS Output Driver Current
010 = 4.5mA LVDS Output Driver Current
011 = Not Used
100 = 3.0mA LVDS Output Driver Current
101 = 2.5mA LVDS Output Driver Current
110 = 2.1mA LVDS Output Driver Current
111 = 1.75mA LVDS Output Driver Current
Bit 3
TERMON
LVDS Internal Termination Bit
0 = Internal Termination Off
1 = Internal Termination On. LVDS output driver current is 2x the current set by ILVDS2:ILVDS0.
216210f
28
LTC2162/LTC2161/LTC2160
Applications Information
OUTOFF
Bit 2
Output Disable Bit
0 = Digital outputs are enabled.
1 = Digital outputs are disabled and have high output impedance.
Note: If the digital outputs are disabled the part should also be put in sleep mode or nap mode.
OUTMODE1: OUTMODE0
Bits 1-0
Digital Output Mode Control Bits
00 = Full Rate CMOS Output Mode
01 = Double Data Rate LVDS Output Mode
10 = Double Data Rate CMOS Output Mode
11 = Not Used
REGISTER A4: DATA FORMAT REGISTER (ADDRESS 04h)
D7
D6
D5
D4
D3
D2
D1
D0
X
X
OUTTEST2
OUTTEST1
OUTTEST0
ABP
RAND
TWOSCOMP
Bits 7-6
Unused, Don’t Care Bits
Bits 5-3
OUTTEST2: OUTTEST0
Digital Output Test Pattern Bits
000 = Digital Output Test Patterns Off
001 = All Digital Outputs = 0
011 = All Digital Outputs = 1
101 = Checkerboard Output Pattern. OF, D15-D0 alternate between 1 0101 0101 0101 0101 and 0 1010 1010 1010 1010.
111 = Alternating Output Pattern. OF, D15-D0 alternate between 0 0000 0000 0000 0000 and 1 1111 1111 1111 1111.
Note: Other bit combinations are not used.
Bit 2
ABP
Alternate Bit Polarity Mode Control Bit
0 = Alternate Bit Polarity Mode Off
1 = Alternate Bit Polarity Mode On. Forces the output format to be Offset Binary.
Bit 1
RAND
Data Output Randomizer Mode Control Bit
0 = Data Output Randomizer Mode Off
1 = Data Output Randomizer Mode On
Bits 0
TWOSCOMP
Two’s Complement Mode Control Bit
0 = Offset Binary Data Format
1 = Two’s Complement Data Format
216210f
29
LTC2162/LTC2161/LTC2160
applications information
GROUNDING AND BYPASSING
The LTC2162/LTC2161/LTC2160 requires a printed circuit
board with a clean unbroken ground plane in the first
layer beneath the ADC. A multilayer board with an internal
ground plane is recommended. Layout for the printed
circuit board should ensure that digital and analog signal
lines are separated as much as possible. In particular, care
should be taken not to run any digital track alongside an
analog signal track or underneath the ADC.
High quality ceramic bypass capacitors should be used at
the VDD, OVDD, VCM, VREF, REFH and REFL pins. Bypass
capacitors must be located as close to the pins as possible. Size 0402 ceramic capacitors are recommended. The
traces connecting the pins and bypass capacitors must
be kept short and should be made as wide as possible.
Of particular importance is the capacitor between REFH
and REFL. This capacitor should be on the same side of
the circuit board as the A/D, and as close to the device
as possible.
The analog inputs, encode signals, and digital outputs
should not be routed next to each other. Ground fill and
grounded vias should be used as barriers to isolate these
signals from each other.
HEAT TRANSFER
Most of the heat generated by the LTC2162/LTC2161/
LTC2160 is transferred from the die through the bottomside exposed pad and package leads onto the printed circuit
board. For good electrical and thermal performance, the
exposed pad must be soldered to a large grounded pad
on the PC board. This pad should be connected to the
internal ground planes by an array of vias.
216210f
30
LTC2162/LTC2161/LTC2160
Typical Applications
Silkscreen Top
Top Side
216210f
31
LTC2162/LTC2161/LTC2160
Typical applications
Inner Layer 2
Inner Layer 3
216210f
32
LTC2162/LTC2161/LTC2160
Typical applications
Inner Layer 4
Inner Layer 5
Bottom Side
216210f
33
LTC2162/LTC2161/LTC2160
Typical applications
C23
2.2µF
SDO
SENSE
VDD
C19
0.1µF
48
C51
0.1µF
AIN+
AIN–
C15
0.1µF
C21
0.1µF
–
+
–
+
CN1
+
–
+
–
PAR/SER
VDD
C18
0.1µF
47
46
45
44
43
42
VDD VDD SENSE VREF SDO GND OF
1
VCM
2
AIN+
3
AIN–
4
GND
5
REFH
6
REFL
LTC2162
7
REFH
8
REFL
9
PAR/SER
10
GND
11
GND
12
VDD
VDD GND ENC+ ENC– CS
13
14
15
16
17
41
40
39
SCK SDI GND D0
18
19
38
37
DNC D15 D14 D13 D12
36
D11
35
D10
34
D9
33
D8
32
OVDD
31
OGND
30
CLKOUT+
29
CLKOUT–
28
D7
27
D6
26
D5
25
D4
20
21
D1
22
D2
23
0VDD
C37
0.1µF
DIGITAL
OUTPUTS
D3
24
2162 TA02
C28
0.1µF
C32
0.1µF
R51
100Ω
SPI PORT
ENCODE
CLOCK
216210f
34
LTC2162/LTC2161/LTC2160
Package Description
UK Package
48-Lead Plastic QFN (7mm × 7mm)
(Reference LTC DWG # 05-08-1704 Rev C)
0.70 ±0.05
5.15 ± 0.05
5.50 REF
6.10 ±0.05 7.50 ±0.05
(4 SIDES)
5.15 ± 0.05
PACKAGE OUTLINE
0.25 ±0.05
0.50 BSC
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED
7.00 ± 0.10
(4 SIDES)
0.75 ± 0.05
R = 0.10
TYP
R = 0.115
TYP
47 48
0.40 ± 0.10
PIN 1 TOP MARK
(SEE NOTE 6)
1
2
PIN 1
CHAMFER
C = 0.35
5.50 REF
(4-SIDES)
5.15 ± 0.10
5.15 ± 0.10
(UK48) QFN 0406 REV C
0.200 REF
0.00 – 0.05
NOTE:
1. DRAWING CONFORMS TO JEDEC PACKAGE OUTLINE MO-220 VARIATION (WKKD-2)
2. DRAWING NOT TO SCALE
3. ALL DIMENSIONS ARE IN MILLIMETERS
4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE
MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.20mm ON ANY SIDE, IF PRESENT
5. EXPOSED PAD SHALL BE SOLDER PLATED
6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE
0.25 ± 0.05
0.50 BSC
BOTTOM VIEW—EXPOSED PAD
216210f
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
35
LTC2162/LTC2161/LTC2160
Typical Application
1.8V
1.8V
2-Tone FFT, fIN = 70MHz and 69MHz
OVDD
VDD
0
–10
–20
16-BIT
ADC CORE
S/H
–30
OUTPUT
DRIVERS
125MHz
D15
•
•
•
D0
–40
–50
–60
–70
–80
–90
–100
CLOCK
CONTROL
CLOCK
CMOS,
DDR CMOS OR
DDR LVDS
OUTPUTS
AMPLITUDE (dBFS)
ANALOG
INPUT
–110
–120
GND
216210 TA03a
OGND
0
20
10
FREQUENCY (MHz)
30
2162 TA03
Related Parts
PART NUMBER
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LTC2259-14/LTC2260-14/
LTC2261-14
LTC2262-14
DESCRIPTION
COMMENTS
14-Bit, 80Msps/105Msps/125Msps
1.8V ADCs, Ultralow Power
14-Bit, 150Msps 1.8V ADC, Ultralow
Power
LTC2266-14/LTC2267-14/ 14-Bit, 80Msps/105Msps/125Msps
LTC2268-14
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LTC2266-12/LTC2267-12/ 12-Bit, 80Msps/105Msps/125Msps
LTC2268-12
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LTC2208
16-Bit, 130Msps 3.3V ADC
LTC2207/LTC2206
16-Bit, 105Msps/80Msps 3.3V ADCs
LTC2217/LTC2216
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RF Mixers/Demodulators
LTC5517
40MHz to 900MHz Direct Conversion
Quadrature Demodulator
LTC5527
400MHz to 3.7GHz High Linearity
Downconverting Mixer
LTC5557
400MHz to 3.8GHz High Linearity
Downconverting Mixer
LTC5575
800MHz to 2.7GHz Direct Conversion
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Amplifiers/Filters
LTC6412
800MHz, 31dB Range, Analog-Controlled
Variable Gain Amplifier
LTC6420-20
1.8GHz Dual Low Noise, Low Distortion
Differential ADC Drivers for 300MHz IF
LTC6421-20
1.3GHz Dual Low Noise, Low Distortion
Differential ADC Drivers
LTC6605-7/LTC6605-10/ Dual Matched 7MHz/10MHz/14MHz
LTC6605-14
Filters with ADC Drivers
Signal Chain Receivers
LTM9002
14-Bit Dual Channel IF/Baseband
Receiver Subsystem
89mW/106mW/127mW, 73.4dB SNR, 85dB SFDR, DDR LVDS/DDR CMOS/CMOS
Outputs, 6mm × 6mm QFN-40
149mW, 72.8dB SNR, 88dB SFDR, DDR LVDS/DDR CMOS/CMOS Outputs,
6mm × 6mm QFN-40
216mW/250mW/293mW, 73.4dB SNR, 85dB SFDR, Serial LVDS Outputs,
6mm × 6mm QFN-40
216mW/250mW/293mW, 70.5dB SNR, 85dB SFDR, Serial LVDS Outputs,
6mm × 6mm QFN-40
1250mW, 77.7dB SNR, 100dB SFDR, CMOS/LVDS Outputs, 9mm × 9mm QFN-64
900mW/725mW, 77.9dB SNR, 100dB SFDR, CMOS Outputs, 7mm × 7mm QFN-48
1190mW/970mW, 81.2dB SNR, 100dB SFDR, CMOS/LVDS Outputs,
9mm × 9mm QFN-64
High IIP3: 21dBm at 800MHz, Integrated LO Quadrature Generator
24.5dBm IIP3 at 900MHz, 23.5dBm IIP3 at 3.5GHz, NF = 12.5dB,
50Ω Single-Ended RF and LO Ports
23.7dBm IIP3 at 2.6GHz, 23.5dBm IIP3 at 3.5GHz, NF = 13.2dB, 3.3V Supply
Operation, Integrated Transformer
High IIP3: 28dBm at 900MHz, Integrated LO Quadrature Generator, Integrated RF
and LO Transformer
Continuously Adjustable Gain Control, 35dBm OIP3 at 240MHz, 10dB Noise Figure,
4mm × 4mm QFN-24
Fixed Gain 10V/V, 1nV/√Hz Total Input Noise, 80mA Supply Current per Amplifier,
3mm × 4mm QFN-20
Fixed Gain 10V/V, 1nV/√Hz Total Input Noise, 40mA Supply Current per Amplifier,
3mm × 4mm QFN-20
Dual Matched 2nd Order Lowpass Filters with Differential Drivers,
Pin-Programmable Gain, 6mm × 3mm DFN-22
Integrated High Speed ADC, Passive Filters and Fixed Gain Differential Amplifiers
216210f
36 Linear Technology Corporation
LT 0711 • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507
●
www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2011