Download LTC1565-31 - 650kHz Continuous Time, Linear Phase Lowpass Filter

LTC1565-31
650kHz Continuous Time,
Linear Phase Lowpass Filter
FEATURES
DESCRIPTION
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The LTC®1565-31 is a 7th order, continuous time, linear
phase lowpass filter. The selectivity of the LTC1565-31,
combined with its linear phase and dynamic range, make
it suitable for filtering in data communications or data
acquisition systems. The filter attenuation is 36dB at
2× fCUTOFF and at least 72dB for frequencies above 3×
fCUTOFF. Unlike comparable LC filters, the LTC1565-31
achieves this selectivity with a linear phase response in
the passband.
With 5% accuracy of the cutoff frequency, the LTC1565-31
can be used in applications requiring pairs of matched
filters, such as transceiver I and Q channels. Furthermore,
the differential inputs and outputs provide a simple interface for these wireless systems.
With a single 5V supply and a 2VP-P input, the LTC1565-31
features an impressive spurious free dynamic range of
75dB. The maximum signal-to-noise ratio is 78dB and it
is achieved with a 2.5VP-P input signal.
The LTC1565-31 features a shutdown mode where power
supply current is typically less than 10μA.
For W-CDMA, 3G, CDMA 2000 and other cellular and
noncellular cutoff frequencies or single-ended I/O, please
contact LTC Marketing for additional information.
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7th Order, 650kHz Linear Phase Filter in an SO-8
Differential Inputs and Outputs
Operates on a Single 5V or a ±5V Supply
Low Offset: 5mV Typical
75dB THD and SNR
78dB SNR
Shutdown Mode
Requires No External Components
Requires No External Clock Signal
APPLICATIONS
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CDMA Basestations
Data Communications
Antialiasing Filters
Smoothing or Reconstruction Filters
Matched Filter Pairs
Replacement for LC Filters
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
Frequency Response
VIN–
2
+IN
+OUT
–IN
–OUT
8
7
VOUT+
VOUT–
0.1μF
4
GND
V–
V
5V
+
SHDN
6
5V
0.1μF
5
15645-31 TA01
GAIN
1.9
–10
1.8
–20
1.7
–30
1.6
–40
1.5
DELAY
–50
1.4
–60
1.3
–70
1.2
–80
1.1
–90
1.0
–100
104
105
106
FREQUENCY (Hz)
DELAY (μs)
LTC1565-31
3
0
GAIN (dB)
VIN+
1
2.0
10
Single 5V Supply, Differential 650kHz Lowpass Filter
0.9
107
1565 G01
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156531fa
1
LTC1565-31
ABSOLUTE MAXIMUM RATINGS
PIN CONFIGURATION
(Note 1)
Total Supply Voltage ............................................... 11V
Power Dissipation .............................................. 500mW
Operating Temperature Range
LTC1565-31CS8 ...................................... 0°C to 70°C
LTC1565-31IS8 ................................... – 40°C to 85°C
Storage Temperature Range ................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec) ................ 300°C
TOP VIEW
+IN 1
8
+OUT
–IN 2
7
–OUT
GND 3
6
V+
V–
5
SHDN
4
S8 PACKAGE
8-LEAD PLASTIC SO
TJMAX = 150°C, θJA = 80°C/ W (NOTE 4)
ORDER INFORMATION
LEAD FREE FINISH
TAPE AND REEL
PART MARKING
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LTC1565-31CS8#PBF
LTC1565-31CS8#TRPBF
156531
8-Lead Plastic SO
0°C to 70°C
LTC1565-31IS8#PBF
LTC1565-31IS8#TRPBF
56531I
8-Lead Plastic SO
–40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges.
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/
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VS = 5V, RLOAD = 10k from each output to AC ground, and Pin 5 open
unless otherwise specified.
PARAMETER
CONDITIONS
MIN
Operating Supply Voltage
4.75
Filter Gain
VIN = 1VP-P, fIN = 25kHz
fIN = 200kHz (Gain Relative to 25kHz)
fIN = 300kHz (Gain Relative to 25kHz)
fIN = 500kHz (Gain Relative to 25kHz)
fIN = 650kHz (Gain Relative to 25kHz)
fIN = 900kHz (Gain Relative to 25kHz)
fIN = 1.3MHz (Gain Relative to 25kHz)
fIN = 2.3MHz (Gain Relative to 25kHz)
Filter Phase
VIN = 1VP-P, fIN = 25kHz
fIN = 200kHz
fIN = 300kHz
fIN = 500kHz
fIN = 600kHz
fIN = 650kHz
fIN = 900kHz
Phase Linearity
TYP
Ratio of 600kHz Phase/300kHz Phase
l
l
l
l
l
l
l
–0.3
–0.2
–0.7
–2.2
–4
l
–162
l
34
l
1.95
0
0
–0.4
–1.6
–3
–11
–36
–72
–13
–101
–150
113
60
36
–92
2
MAX
UNITS
11
V
0.3
0.1
–0.1
–0.95
–2
–7
–31
dB
dB
dB
dB
dB
dB
dB
dB
–138
85
Deg
Deg
Deg
Deg
Deg
Deg
Deg
2.03
Wideband Noise
Noise BW = DC to 2 • fCUTOFF
118
μVRMS
THD
fIN = 100kHz, 1VP-P (Note 2)
86
dB
Filter Differential DC Swing
Maximum Difference Between Pins 7 and 8
VS = 5V
VS = ±5V
±1.7
±2.3
V
V
2
l
l
±1.4
±2.2
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156531fa
LTC1565-31
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VS = 5V, RLOAD = 10k from each output to AC ground, and Pin 5 open
unless otherwise specified.
PARAMETER
CONDITIONS
MIN
Input Bias Current
0.1
Input Offset Current
Common Mode, VIN = 2.5V
Differential
Input Resistance
TYP
MAX
0.3
0.6
VS = 5V
VS = ±5V (Note 5)
Output DC Offset Drift
VS = 5V
VS = ±5V
Ground Voltage (Pin 3) in
Single Supply Applications
VS = 5V
l
2.49
SHDN Pin Logic Thresholds
VS = 5V, Minimum Logical “1”
VS = 5V, Maximum Logical “0”
l
l
3.3
VS = ±5V, Minimum Logical “1”
VS = ±5V, Maximum Logical “0”
l
l
2.4
μA
±10
nA
75
145
MΩ
MΩ
3
pF
Input Capacitance
Output DC Offset (Note 3)
UNITS
±5
±5
±12
±12
–400
–400
mV
mV
μV/°C
μV/°C
2.51
2.52
V
4.2
V
V
2.9
V
V
SHDN Pin Pull-Up Current
VS = 5V
VS = ±5V
Power Supply Current
VS = 5V
VS = ±5V
l
l
24
25
31
33
mA
mA
Power Supply Current in Shutdown Mode
Shutdown. Includes SHDN Pull-Up Current
VS = 5V
VS = ±5V
l
l
8
20
16
40
μA
μA
5
9
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: Input and output voltages expressed as peak-to-peak numbers are
assumed to be fully differential.
μA
μA
Note 3: Output DC offset is measured between Pin 8 and Pin 7 with Pin 1
and Pin 2 connected to Pin 3.
Note 4: Thermal resistance varies depending upon the amount of PC board
metal attached to the device. θJA is specified for a 3.8 square inch test
board covered with 2 oz copper on both sides.
Note 5: Output DC offset measurements are performed by automatic test
equipment approximately 0.5 seconds after application of power.
TYPICAL PERFORMANCE CHARACTERISTICS
Passband Gain and Delay
vs Frequency
Frequency Response
2.0
10
0.5
2.0
GAIN
1.8
–0.5
1.8
–20
1.7
–1.0
1.7
–30
1.6
–1.5
1.6
1.5
DELAY
1.4
–50
1.3
–60
–2.0
5V
1.9
±5V
1.5
DELAY
–2.5
1.4
–3.0
1.3
–70
1.2
–80
1.1
–3.5
1.2
–90
1.0
–4.0
1.1
–100
104
105
106
FREQUENCY (Hz)
0.9
107
TA = 25°C
–4.5
25k
100k
FREQUENCY (Hz)
1565 G01
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DELAY (μs)
–40
GAIN (dB)
0
–10
DELAY (μs)
GAIN (dB)
GAIN
1.9
0
1.0
1M
1565 G02
156531fa
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LTC1565-31
TYPICAL PERFORMANCE CHARACTERISTICS
Passband Gain vs Frequency
Over Temperature
0.4
VS = 5V
0.3
–40°C
0.1
GAIN (dB)
GAIN (dB)
0.2
85°C
0
25°C
–0.1
–40
–40
–50
–50
–60
–60
GAIN (dB)
0.5
Stopband Gain vs Frequency
Over Temperature
Stopband Gain vs Frequency
VS = 5V
–70
VS = 5V
–40°C
25°C
85°C
–70
–0.2
–0.3
–80
–80
VS = ±5V
–0.4
–0.5
25k
100k
FREQUENCY (Hz)
–90
1.5
400k
1.8
2.4
2.1
FREQUENCY (MHz)
2.7
1565 G03
2.7
3.0
70
Supply Current vs Temperature
26
VIN = 200mVP-P
VS = 5V
TA = 25°C
SUPPLY CURRENT (mA)
80
VIN = 1VP-P
VS = 5V
100 TA = 25°C
PSRR (dB)
90
CMRR (dB)
2.4
2.1
FREQUENCY (MHz)
1565 G05
Power Supply Rejection Ratio
Common Mode Rejection Ratio
80
1.8
1565 G04
110
60
50
70
25
VS = ±5V
VS = 5V
24
40
60
50
103
–90
1.5
3.0
104
105
106
FREQUENCY (Hz)
107
30
103
104
105
106
FREQUENCY (Hz)
1565 G06
107
23
–50 –30
1565 G07
30
50
–10 10
TEMPERATURE (°C)
70
90
1565 G08
PIN FUNCTIONS
+IN, –IN (Pins 1, 2): Input Pins. Signals can be applied
to either or both input pins. The typical DC gain from differential inputs (Pin 1 to Pin 2) to the differential outputs
(Pin 8 to Pin 7) is 1.0V/V. The input range is described in
the Applications Information section.
GND (Pin 3): Ground. The ground pin is the reference
voltage for the filter and is internally biased to one-half
the total power supply voltage of the filter, maximizing the
dynamic range of the filter. For single supply operation,
the ground pin should be bypassed with a quality 0.1μF
4
ceramic capacitor to Pin 4. For dual supply operation,
connect Pin 3 to a high quality DC ground. A ground
plane should be used. A poor ground will increase noise
and distortion.
The impedance seen at Pin 3 is 2.5kΩ in normal mode. In
shutdown, the pin is internally biased to the same levels
as normal mode. The impedance in shutdown mode
is typically 500kΩ but varies with supply voltage and
temperature.
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156531fa
LTC1565-31
PIN FUNCTIONS
V–, V+ (Pins 4, 6): Power Supply Pins. For a single 5V
supply (Pin 4 grounded), a quality 0.1μF ceramic bypass
capacitor is required from the positive supply pin (Pin 6)
to the negative supply pin (Pin 4). The bypass should be
as close as possible to the IC. For dual supply applications
(Pin 3 is grounded), bypass Pin 6 to Pin 3 and Pin 4 to
Pin 3 with a quality 0.1μF ceramic capacitor.
The maximum voltage difference between the ground
pin (Pin 3) and the positive supply pin (Pin 6) should not
exceed 5.5V.
SHDN (Pin 5): Shutdown. When the Pin 5 voltage is low,
the LTC1565-31 goes into the current saving shutdown
mode. Pin 5 has a 4μA pull-up current. Leaving Pin 5 open
will place the LTC1565-31 in its normal operating mode.
– OUT, +OUT (Pins 7, 8): Output Pins. Pins 7 and 8 are the
filter differential output. Each pin can drive 1kΩ or 300pF
loads. The common mode voltage at the output pins is
the same as the voltage at Pin 3.
BLOCK DIAGRAM
+IN 1
+
8 +OUT
–
R
+
R
–
–
7th ORDER
LINEAR
PHASE
FILTER
NETWORK
OUTPUT
BUFFER
OUTPUT
BUFFER
7 –OUT
–IN 2
+
INPUT BUFFERS
WITH COMMON MODE
TRANSLATION CIRCUIT
V+
~1M
SHUTDOWN
SWITCH
5k
6 V+
GND 3
5k
~1M
SHUTDOWN
SWITCH
V+
V–
V– 4
4μA
SHUTDOWN
5
SHDN
1565-31 BD
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156531fa
5
LTC1565-31
APPLICATIONS INFORMATION
Interfacing to the LTC1565-31
Input Common Mode and Differential Voltage Range
The difference between the voltages at Pin 1 and Pin 2 is
the “differential input voltage.” The average of the voltages
at Pin 1 and Pin 2 is the “common mode input voltage.”
The difference between the voltages at Pin 7 and Pin 8
is the “differential output voltage.” The average of the
voltages at Pin 7 and Pin 8 is the “common mode output
voltage.” The input and output common mode voltages are
independent. The input common mode voltage is set by the
signal source, if DC coupled, or by the biasing network if
AC coupled (Figures 1 and 2). The output common mode
voltage is equal to the voltage of Pin 3, the GND pin. The
GND pin is biased to one-half of the supply voltage by an
internal resistive divider (see Block Diagram). To alter the
common mode output voltage, Pin 3 can be driven with
an external voltage source or resistor network. If external
resistors are used, it is important to note that the internal
5k resistors can vary ± 20% (their ratio only varies ±1%).
The output can also be AC coupled.
The range of voltage each input can support while operating in its linear region is typically 0.8V to 3.7V for a single
5V supply and – 4.2V to 3.2V for a ±5V supply. Therefore,
the filter can accept a variety of common mode input voltages. Figures 3 and 4 show the THD of the filter versus
common mode input voltage with a 2VP-P differential
input signal.
1
2
+
–
VIN+
+
–
+IN
–IN
VIN–
–OUT
VOUT+
7
VOUT–
4
V+
6
SHDN
5
GND
V–
–40
VS = ±5V
THD (dB)
–50
–70
–80
–90
–30
0.1μF
THD (dB)
Figure 1
2
+IN
+OUT
–IN
–OUT
100k
1μF
8
VOUT+
7
VOUT–
5V
LTC1565-31
3
4
GND
V–
V+
6
SHDN
5
AC COUPLED INPUT
VIN (COMMON MODE) = VOUT (COMMON MODE)
=
Figure 2
V+
2
VIN = 2VP-P
fIN = 100kHz
0.5
3.0
1.0
2.0
2.5
1.5
INPUT COMMON MODE VOLTAGE (V)
3.5
1565-31 F04
Figure 4. THD vs Common Mode Input Voltage
0.1μF
15645-31 F02
6
–60
–80
1
VIN
–50
–70
0.1μF
VIN– 0.1μF 100k
VS = 5V
–40
V + + VIN–
VIN (COMMON MODE) = IN
2
V + + VOUT– V+
VOUT (COMMON MODE) = OUT
=
2
2
+
–
5
Figure 3. THD vs Common Mode Input Voltage
DC COUPLED INPUT
+
VIN = 2VP-P
fIN = 100kHz
–5 –4 –3 –2 –1 0 1 2 3 4
INPUT COMMON MODE VOLTAGE (V)
15645-31 F01
+
–
–60
1565-31 F03
5V
LTC1565-31
3
0.1μF
+OUT
8
–30
Figure 5 shows the THD and S/N ratio versus differential
input voltage level for both a single 5V supply and a ±5V
supply. The common mode voltage of the input signal is
one-half the total power supply voltage of the filter. The
spurious free dynamic range, where the THD and S/N
ratio are equal, is 75dB to 76dB when the differential input
voltage level is 2VP-P; that is, for a single 5V supply, the
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156531fa
LTC1565-31
APPLICATIONS INFORMATION
THD, SNR (dB)
–40
Output Common Mode and Differential Voltage Range
THD: VS = 5V, VCM = 2.5V
THD: VS = ±5V, VCM = 0V
SNR
fIN = 100kHz
The output is a fully differential signal with a common mode
level equal to the voltage at Pin 3. The specifications in
the Electrical Characteristics table assume the inputs are
driven differentially and the output is observed differentially.
However, Pin 8 can be used as a single-ended output by
simply floating Pin 7. Pin 7 can be used as an inverting
single-ended output by floating Pin 8. Using Pins 7 or 8
as single-ended outputs will decrease the performance.
–50
–60
–70
–80
–90
0.5
1.0
1.5
2.0
2.5
3.0
DIFFERENTIAL INPUT (P-P)
3.5
1565-31 F05
Figure 5. Dynamic Range Diff-In, Diff-Out
input voltages are Pin 1 = 2.5V DC ±0.5V and Pin 2 = 2.5V
DC ±0.5V. Also note Figure 5 shows a 78dB SNR ratio for
higher THD levels.
As seen in Figures 3 and 4, the spurious free dynamic
range can be optimized by setting the input common mode
voltage slightly below one-half of the power supply voltage,
i.e., 2V for a single 5V supply and –0.5V for a ±5V supply.
Figure 6 shows the THD and SNR ratio versus differential
input voltage level for both a single 5V supply and a ±5V
supply when the common mode input voltage is 2V and
–0.5V respectively.
The common mode output voltage can be adjusted by overdriving the voltage present on Pin 3. The best performance
is achieved using a common mode output voltage that is
equal to mid supply (the default Pin 3 voltage). Figures
7 and 8 illustrate the THD versus output common mode
voltage for a 2VP-P differential input voltage and a common
mode input voltage that is 0.5V below mid supply.
0
VIN = 2VP-P 100kHz
VS = 5V
VIN(CM) = 2V
–10
–20
THD (dB)
–30
–30
–40
–50
–60
–70
For best performance, the inputs should be driven differentially. For single-ended signals, connect the unused
input to Pin 3 or a common mode reference.
–80
1.0
2.0
2.5
3.5
4.0
1.5
3.0
COMMON MODE OUTPUT VOLTAGE (V)
1565-31 F07
–30
0
VIN = 2VP-P 100kHz
–10 VS = ±5V
VIN(CM) = –0.5V
–20
–50
–30
–60
THD (dB)
THD, SNR (dB)
–40
Figure 7. THD vs Common Mode Output Voltage
THD: VS = 5V, VCM = 2V
THD: VS = ±5V, VCM = –0.5V
SNR
fIN = 100kHz
–70
–40
–50
–60
–80
–70
–90
0.5
1.5
2.0
2.5
3.0
1.0
DIFFERENTIAL INPUT VOLTAGE (VP-P)
3.5
1565-31 F06
Figure 6. THD vs VIN for a Common Mode
Input Voltage 0.5V Below Mid Supply
–80
–90
–4
0
1
2
–3 –2 –1
3
COMMON MODE OUTPUT VOLTAGE (V)
4
1565-31 F08
Figure 8. THD vs Common Mode Output Voltage
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156531fa
7
LTC1565-31
APPLICATIONS INFORMATION
in the filter passband and cannot be removed with post
filtering (Table 1). Table 2 lists the typical change in wideband noise with supply voltage.
Output Drive
Pin 7 and Pin 8 can drive a 1kΩ or 300pF load connected
to AC ground with a ± 0.5V signal (corresponding to a
2VP-P differential signal). For differential loads (loads
connected from Pin 7 to Pin 8) the outputs can produce a
2VP-P differential signal across 2kΩ or 150pF. For smaller
signal amplitudes the outputs can drive correspondingly
larger loads.
Table 1. Wideband Noise vs Bandwidth, Single 5V Supply
BANDWIDTH
TOTAL INTEGRATED NOISE
DC to fCUTOFF
104μVRMS
DC to 2 • fCUTOFF
118μVRMS
Table 2. Wideband Noise vs Supply Voltage, fCUTOFF = 650kHz
Noise
The wideband noise of the filter is the RMS value of the
device’s output noise spectral density. The wideband noise
data is used to determine the operating signal-to-noise at
a given distortion level. Most of the noise is concentrated
POWER SUPPLY
TOTAL INTEGRATED NOISE
DC TO 2 • fCUTOFF
5V
118μVRMS
± 5V
120μVRMS
TYPICAL APPLICATIONS
Test Circuit for Single 5V Supply Operation
4.99k
AMPLIFIERS A1, A2 AND A3 ALLOW THE USE OF A
GROUND-REFERENCED SINGLE-ENDED AC SOURCE AS THE
INPUT SIGNAL AND A SEPARATE GROUND-REFERENCED DC
SOURCE TO PROVIDE THE INPUT DC COMMON MODE VOLTAGE
AMPLIFIERS A4 AND A5 ALLOW MONITORING/MEASURING
THE DIFFERENTIAL OUTPUT WITH A SINGLE-ENDED,
GROUND-REFERENCED INSTRUMENT
5V
4.99k
2.49k
2
3
–
0.1μF
7
A1
LT®1809
6
+
4
10μF
2.49k
4.99k
5V
4.99k
VIN
2
–
+
–
3
0.1μF
7
+VIN/2 + VCM 1
6
A2
VCM 2.49k
5V
+LT1809
–VIN/2 + VCM 2
4
4.99k
+IN
–IN
10μF
+OUT
–OUT
8
4.99k
7
2.49k
GND
V+
+
6
V–
SHDN
A4
LT1809
6
VOUT
(SINGLE ENDED)
5V
1k
0.1μF
4
0.1μF
7
4
0.1μF
4.99k
3
–
2.49k
LTC1565-31
3
2
5
5V
0.01μF
19k
5V
2
4.99k
2
–
7
6
A3
2.49k
3
+LT1809
4
8
–
0.1μF
V+/2
1k
3
+
0.1μF
7
A5
LT1812
6
20Ω
2.2μF
4
0.1μF
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1565-31 TA08
156531fa
LTC1565-31
TYPICAL APPLICATIONS
Single-Ended Input/Output Dual Supply Filter
4.99k
5V
VIN
1
2
+OUT
+IN
–OUT
–IN
8
4.99k
2
–
7
2.49k
3
+
0.1μF
7
6
LT1809
4
LTC1565-31
3
GND
V+
6
SHDN
5
5V
0.1μF
–5V
R2
2.49k
0.1μF
4
V–
VOUT
0.1μF
–5V
1565-31 TA09
0.1μF
NOTE: FOR SINGLE 5V SUPPLY CONNECTION, PIN 4 (LTC1565-31)
AND PIN 4 (LT1809) SHOULD BE GROUNDED AND RESISTOR R2
SHOULD BE DC BIASED AT APPROXIMATELY 2.5V
(SEE TEST CIRCUIT FOR SINGLE SUPPLY OPERATION)
A Fully Differential Filter with Adjustable Output Common Mode Voltage
VIN+*
1
VIN–*
2
+IN
+OUT
–IN
–OUT
8
VOUT+
7
VOUT–
VOUT(CM) = V– +
(V+ – V–)R2
R1 + R2
LTC1565-31
3
GND
V+
6
5V
0.1μF
4
–5V
V–
SHDN
5
0.1μF
–3V ≤ VOUT(CM) ≤ 3V
5V
V+
2
–
3
+
R1
7
LT1812
*–3.4V ≤ VIN(CM) ≤ 2.5V
VIN(CM) CAN BE EQUAL OR
DIFFERENT FROM VOUT(CM)
0.1μF
NOTE: FOR SINGLE 5V SUPPLY OPERATION,
PIN 4 (LTC1565-31), PIN 4 (LT1812) AND
RESISTOR R2 SHOULD BE GROUNDED
6
4
R2
0.1μF
V–
–5V
0.1μF
100pF
1565-31 TA10
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156531fa
9
LTC1565-31
TYPICAL APPLICATIONS
Simple Pulse Shaping Circuit for Single 5V Operation, 1.25Mbps 2 Level Data
5V
1.25Mbps
DATA
1
2
4.99k
+IN
–IN
+OUT
–OUT
8
VOUT+
7
VOUT–
LTC1565-31
3
0.1μF
4
GND
–
V
V+
6
SHDN
5
5V
500mV/DIV
4.99k
4.99k
0.1μF
15645-31 TA04
250ns/DIV
1565-31 TA05
Simple Pulse Shaping Circuit for Single 5V Operation, 2Mbps (1Msps) 4 Level Data
5V
4.99k
4.99k
1
10k
2
D0
4.99k
+OUT
–IN
–OUT
8
VOUT+
7
VOUT–
LTC1565-31
3
0.1μF
+IN
500mV/DIV
D1
1Msps
DATA
4
GND
V–
V+
6
SHDN
5
5V
0.1μF
15645-31 TA06
200ns/DIV
10
www.BDTIC.com/Linear
1565-31 TA07
156531fa
LTC1565-31
TYPICAL APPLICATIONS
Narrowband Cellular Basestation Receiver
LTC1565-31
LPF
0°
ADC
I
RF/IF
SECTION
90°
LO
DSP
Q
90°
LTC1565-31
LPF
ADC
1565-31 TA03
PACKAGE DESCRIPTION
S8 Package
8-Lead Plastic Small Outline (Narrow .150 Inch)
(Reference LTC DWG # 05-08-1610)
.189 – .197
(4.801 – 5.004)
NOTE 3
.045 ±.005
.050 BSC
8
.245
MIN
7
6
5
.160 ±.005
.150 – .157
(3.810 – 3.988)
NOTE 3
.228 – .244
(5.791 – 6.197)
.030 ±.005
TYP
1
RECOMMENDED SOLDER PAD LAYOUT
.010 – .020
× 45°
(0.254 – 0.508)
.008 – .010
(0.203 – 0.254)
3
4
.053 – .069
(1.346 – 1.752)
.004 – .010
(0.101 – 0.254)
0°– 8° TYP
.016 – .050
(0.406 – 1.270)
NOTE:
1. DIMENSIONS IN
2
.014 – .019
(0.355 – 0.483)
TYP
INCHES
(MILLIMETERS)
2. DRAWING NOT TO SCALE
3. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm)
.050
(1.270)
BSC
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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.
SO8 0303
156531fa
11
LTC1565-31
TYPICAL APPLICATION
Selective 620kHz CDMA Filter
R5
1k
5V
R4
1.13k
C6
0.1μF R6
1k
C3
18pF
R1
562Ω
R2
562Ω
1
R3
1.24k
2
VIN1
3
C1
150pF
R7
562Ω
C2
1000pF
R8
562Ω
8
U1
LT1813
4
C4
18pF
1
C5
180pF
7
2
6
FGND 3
5
C7
0.1μF
R9
1.24k
4
+IN
+OUT
–IN
–OUT
U2
LTC1565-31
GND
V–
R10
1.13k
VOUT1
7
V+
6
SHDN
5
R11
1k
VIN2
8
VOUT2
C8
0.1μF
15645-31 TA11
5V
R12
1k
Frequency Response
0
–6
GAIN (dB)
–12
–18
–24
–30
–36
–42
–48
1M
100k
FREQUENCY (Hz)
1565 TA12
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LTC1560-1
1MHz/500kHz Continuous Time, Low Noise, Lowpass Elliptic Filter
fCUTOFF = 500kHz or 1MHz
LTC1562/LTC1562-2
Universal 8th Order Active RC Filters
fCUTOFF(MAX) = 150kHz (LTC1562),
fCUTOFF(MAX) = 300kHz (LTC1562-2)
LTC1563-2/LTC1563-3
4th Order Active RC Lowpass Filters
fCUTOFF(MAX) = 256kHz
LTC1569-6/LTC1569-7
Self Clocked, 10th Order Linear Phase Lowpass Filters
fCLK/fCUTOFF = 64/1, fCUTOFF(MAX) = 75kHz (LTC1569-6)
fCLK/fCUTOFF = 32/1, fCUTOFF(MAX) = 300kHz (LTC1569-7)
Corporation
www.BDTIC.com/Linear
12 Linear Technology
156531fa
LT 0809 REV A • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507
●
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© LINEAR TECHNOLOGY CORPORATION 2000