Download MAX2056 800MHz to 1000MHz Variable-Gain Amplifier with Analog Gain Control General Description

19-3508; Rev 0; 2/05
KIT
ATION
EVALU
LE
B
A
IL
A
AV
800MHz to 1000MHz Variable-Gain
Amplifier with Analog Gain Control
The MAX2056 general-purpose, high-performance variable-gain amplifier (VGA) is designed to operate in the
800MHz to 1000MHz frequency range*. This device features 15.5dB of gain, 4.5dB of noise figure, and an output 1dB compression point of 23.5dBm. The MAX2056
also provides an exceptionally high OIP3 level of
39dBm, which is maintained over the entire attenuation
range. In addition, the on-chip analog attenuators yield
infinite control and high attenuation accuracy over
selectable 22dB or 44dB control ranges. Each of these
features makes the MAX2056 an ideal VGA for cellular
band GSM, cdma2000®, W-CDMA, and iDEN® transmitter and power amplifier AGC circuits.
The MAX2056 is pin compatible with the MAX2057
1700MHz to 2500MHz VGA, making this family of
amplifiers ideal for applications where a common PC
board layout is used for both frequency bands.
The MAX2056 operates from a single +5V supply and is
available in a compact 36-pin thin QFN package (6mm
x 6mm x 0.8mm) with an exposed pad. Electrical performance is guaranteed over the extended -40°C to
+85°C temperature range.
Features
♦ 800MHz to 1000MHz RF Frequency Range*
♦ 39dBm Constant OIP3 (Over All Gain Settings)
♦ 23.5dBm Output 1dB Compression Point
♦ 15.5dB Typical Gain at Maximum Gain Setting
♦ 0.15dB Gain Flatness Over 100MHz Bandwidth
♦ 4.5dB Noise Figure at Maximum Gain Setting
(Using 1 Attenuator)
♦ Two Gain-Control Ranges: 22dB and 44dB
♦ Analog Gain Control
♦ Single +5V Supply Voltage
♦ Pin Compatible with MAX2057, 1700MHz to
2500MHz RF VGA
♦ External Current-Setting Resistors Provide Option
for Operating VGA in Reduced-Power/ReducedPerformance Mode
♦ Lead-Free Package Available
*Note: Operation beyond this range is possible, but has not been
characterized.
Applications
GSM 850/GSM 900 2G and 2.5G EDGE BaseStation Transmitters and Power Amplifiers
Cellular cdmaOne™, cdma2000, and Integrated
Digital Enhanced Network (iDEN) Base-Station
Transmitters and Power Amplifiers
W-CDMA 850MHz and Other 3G Base-Station
Transmitters and Power Amplifiers
Transmitter Gain Control
Receiver Gain Control
Broadband Systems
Automatic Test Equipment
Digital and Spread-Spectrum Communication
Systems
Microwave Terrestrial Links
cdmaOne is a trademark of CDMA Development Group.
cdma2000 is a registered trademark of Telecommunications
Industry Association.
iDEN is a registered trademark of Motorola, Inc.
Ordering Information
PART
TEMP
RANGE
PIN-PACKAGE
PKG
CODE
MAX2056ETX
-40°C to +85°C
36 Thin QFN-EP**
T3666-2
6mm x 6mm
MAX2056ETX-T
-40°C to +85°C
36 Thin QFN-EP**
T3666-2
6mm x 6mm
MAX2056ETX+D
-40°C to +85°C
36 Thin QFN-EP**
T3666-2
6mm x 6mm
MAX2056ETX+TD
-40°C to +85°C
36 Thin QFN-EP**
T3666-2
6mm x 6mm
**EP = Exposed paddle.
+ = Lead (Pb) free.
D = Dry pack.
T = Tape-and-reel package.
Pin Configuration/Functional Diagram appears at end of data
sheet.
________________________________________________________________ Maxim Integrated Products
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
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1
MAX2056
General Description
MAX2056
800MHz to 1000MHz Variable-Gain
Amplifier with Analog Gain Control
ABSOLUTE MAXIMUM RATINGS
VCC to GND ...........................................................-0.3V to +5.5V
VCNTL to GND (with VCC applied)................................0 to 4.75V
Current into VCNTL Pin (VCC grounded) .............................40mA
All Other Pins to GND.................................-0.3V to (VCC + 0.3V)
RF Input Power (IN, IN_A, ATTN_OUT, OUT_A) ............+20dBm
RF Input Power (AMP_IN)...............................................+12dBm
θJA (natural convection)...................................................35°C/W
θJA (1m/s airflow) .............................................................31°C/W
θJA (2.5m/s airflow) ..........................................................29°C/W
θJC (junction to exposed paddle) ....................................10°C/W
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Junction Temperature ......................................................+150°C
Lead Temperature (soldering, 10s) .................................+300°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
DC ELECTRICAL CHARACTERISTICS
(VCC = +4.75V to +5.25V, no RF signals applied, all input and output ports terminated with 50Ω, TA = -40°C to +85°C, unless otherwise noted. Typical values are at VCC = +5.0V, TA = +25°C, unless otherwise noted.)
PARAMETER
CONDITIONS
Supply Voltage
MIN
TYP
MAX
4.75
5
5.25
V
136
167
mA
Supply Current
R1 = 1.2kΩ, R2 = 3.92kΩ (Note 1)
RSET1 Current
R1 = 1.2kΩ (Note 1)
1
RSET2 Current
R2 = 3.92kΩ (Note 1)
0.33
Gain-Control Voltage Range
(Note 2)
1.0
Gain-Control Pin Input Resistance
VCNTL = 1V to 4.5V
250
UNITS
mA
mA
4.5
500
V
kΩ
AC ELECTRICAL CHARACTERISTICS
(Typical Operating Circuit with one attenuator connected, VCC = +4.75V to +5.25V, TA = -40°C to +85°C, unless otherwise noted.
Typical values are at VCC = +5.0V, R1 = 1.2kΩ, R2 = 3.92kΩ, POUT = +5dBm, fIN = 900MHz, VCNTL = 1V, 50Ω system impedance,
second attenuator is not connected, TA = +25°C, unless otherwise noted.) (Note 3)
PARAMETER
CONDITIONS
Frequency Range
Gain
TYP
800
TA = +25°C
TA = +25°C to -40°C
Maximum Gain Variation
TA = +25°C to +85°C
MAX
UNITS
1000
MHz
15.5
VCNTL = 1V
+0.82
VCNTL = 1.8V
+0.26
VCNTL = 2.6V
+0.25
VCNTL = 3.5V
-0.18
VCNTL = 1V
-0.51
VCNTL = 1.8V
-0.11
VCNTL = 2.6V
-0.16
VCNTL = 3.5V
+0.09
Reverse Isolation
Noise Figure
MIN
29
(Note 4)
Output 1dB Compression Point
dB
dB
dB
4.5
dB
+23.5
dBm
Output 2nd-Order Intercept Point
From maximum gain to 15dB attenuation,
measured at f1 + f2 (Note 5)
+54
dBm
Output 3rd-Order Intercept Point
From maximum gain to 15dB attenuation (Note 5)
+39
dBm
2
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800MHz to 1000MHz Variable-Gain
Amplifier with Analog Gain Control
(Typical Operating Circuit with one attenuator connected, VCC = +4.75V to +5.25V, TA = -40°C to +85°C, unless otherwise noted.
Typical values are at VCC = +5.0V, R1 = 1.2kΩ, R2 = 3.92kΩ, POUT = +5dBm, fIN = 900MHz, VCNTL = 1V, 50Ω system impedance,
second attenuator is not connected, TA = +25°C, unless otherwise noted.) (Note 3)
PARAMETER
Output 3rd-Order Intercept Point
Variation Over Temperature
CONDITIONS
MIN
TYP
TA = +25°C to +85°C
-0.46
TA = +25°C to -40°C
+1.35
MAX
UNITS
dB
2nd Harmonic
From maximum gain to 15dB attenuation, POUT =
+5dBm
-55
dBc
3rd Harmonic
From maximum gain to 15dB attenuation, POUT =
+5dBm
-68
dBc
RF Gain-Control Range
fRF = 800MHz to 1000MHz,
VCNTL = 1V to 4.5V
One attenuator
18.3
22.3
Two attenuators
36.6
44.6
RF Gain-Control Slope
dB
-10.7
dB/V
Maximum RF Gain-Control Slope
Maximum slope vs. gain-control voltage
-17.2
dB/V
Gain Flatness Over 100MHz Bandwidth
Peak-to-peak for all settings
0.15
dB
Attenuator Switching Time
15dB attenuation change (Note 6)
500
ns
Attenuator Insertion Loss
Second attenuator (IN_A, OUT_A)
1.7
dB
Input Return Loss
Entire band, all gain settings
15
dB
Output Return Loss
Entire band, all gain settings
15
dB
Group Delay
Input/output 50Ω lines de-embedded
600
ps
Group Delay Flatness Over 100MHz
Bandwidth
Peak to peak
100
ps
Group Delay Change vs. Gain Control
VCNTL = 1V to 4V
100
ps
Insertion Phase Change vs. Gain Control
VCNTL = 1V to 4V
20
degrees
Note 1: Total supply current reduces as R1 and R2 are increased.
Note 2: Operating outside this range for extended periods may affect device reliability. Limit pin input current to 40mA when VCC is
not present.
Note 3: All limits include external component losses, unless otherwise noted.
Note 4: Noise figure increases by approximately 1dB for every 1dB of gain reduction.
Note 5: f1 = 900MHz, f2 = 901MHz, +5dBm/tone at OUT.
Note 6: Switching time is measured from 50% of the control signal to when the RF output settles to ±1dB.
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3
MAX2056
AC ELECTRICAL CHARACTERISTICS (continued)
Typical Operating Characteristics
One Attenuator Configuration
(Typical Application Circuit with one attenuator connected, VCC = +5.0V, R1 = 1.2kΩ, R2 = 3.92kΩ, fIN = 900MHz maximum gain
setting, POUT = +5dBm, linearity measured at POUT = +5dBm/tone, TA = +25°C, unless otherwise noted.)
INPUT RETURN LOSS
vs. RF FREQUENCY
140
130
TA = +85°C
TA = -40°C
TA = +25°C
20
TA = +85°C
30
30
RF FREQUENCY (MHz)
GAIN vs. VCNTL
GAIN vs. RF FREQUENCY
REVERSE ISOLATION
vs. RF FREQUENCY
MAX2056 toc04
17
TA = -40°C
16
0
13
-5
12
-10
TA = +25°C
14
TA = +85°C
ISOLATION (dB)
GAIN (dB)
15
TA = +85°C
35
3.5
4.0
20
700 800 900 1000 1100 1200 1300 1400 1500
RF FREQUENCY (MHz)
RF FREQUENCY (MHz)
VCNTL (V)
INPUT RETURN LOSS
vs. RF FREQUENCY
OUTPUT RETURN LOSS
vs. RF FREQUENCY
0
MAX2056 toc07
0
10
MAXIMUM GAIN
15
20
25
21dB GAIN REDUCTION
30
5
OUTPUT RETURN LOSS (dB)
5
TA = -40°C
700 800 900 1000 1100 1200 1300 1400 1500
GAIN vs. RF FREQUENCY
23
18
MAXIMUM GAIN
13
10
MAXIMUM GAIN
15
GAIN (dB)
3.0
TA = +25°C
25
MAX2056 toc08
2.5
30
TA = +85°C
11
2.0
MAX2056 toc06
700 800 900 1000 1100 1200 1300 1400 1500
5.250
TA = +25°C
1.5
TA = +85°C
RF FREQUENCY (MHz)
5.125
15
1.0
20
VCC (V)
5.000
TA = -40°C
5
TA = -40°C
15
700 800 900 1000 1100 1200 1300 1400 1500
4.875
20
10
TA = +25°C
10
25
MAX2056 toc05
100
4.750
4
TA = +25°C
MAX2056 toc03
MAX2056 toc02
15
5
25
110
GAIN (dB)
TA = -40°C
10
0
MAX2056 toc09
120
5
INPUT RETURN LOSS (dB)
150
SUPPLY CURRENT (mA)
0
MAX2056 toc01
160
OUTPUT RETURN LOSS
vs. RF FREQUENCY
OUTPUT RETURN LOSS (dB)
SUPPLY CURRENT vs. VCC
INPUT RETURN LOSS (dB)
MAX2056
800MHz to 1000MHz Variable-Gain
Amplifier with Analog Gain Control
8
3
-2
20
-7
25
21dB GAIN REDUCTION
-12
22dB GAIN REDUCTION
-17
30
700 800 900 1000 1100 1200 1300 1400 1500
700 800 900 1000 1100 1200 1300 1400 1500
700 800 900 1000 1100 1200 1300 1400 1500
RF FREQUENCY (MHz)
RF FREQUENCY (MHz)
RF FREQUENCY (MHz)
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800MHz to 1000MHz Variable-Gain
Amplifier with Analog Gain Control
One Attenuator Configuration
(Typical Application Circuit with one attenuator connected, VCC = +5.0V, R1 = 1.2kΩ, R2 = 3.92kΩ, fIN = 900MHz maximum gain
setting, POUT = +5dBm, linearity measured at POUT = +5dBm/tone, TA = +25°C, unless otherwise noted.)
REVERSE ISOLATION
vs. RF FREQUENCY
40
35
30
5
4
3
VCC = 5.25V
5
4
VCC = 5.00V
VCC = 4.75V
3
TA = -40°C
2
2
800
850
950
800
1000
OUTPUT IP3 vs. FREQUENCY
TA = +25°C
VCC = 5.25V
45
TA = +25°C
VCC = 5.00V
39
38
VCC = 4.75V
TA = +85°C
50
INPUT IP3 (dBm)
39
37
37
850
900
950
850
900
950
1000
0
35
TA = +85°C
30
MAX2056 toc17
36
34
ATTENUATION (dB)
20
25
25
TA = -40°C
60
TA = +25°C
55
TA = +85°C
50
40
32
15
20
45
25
20
15
OUTPUT IP2 vs. RF FREQUENCY
OUTPUT IP2 (dBm)
OUTPUT IP3 (dBm)
40
10
10
65
38
5
5
ATTENUATION (dB)
40
MAX2056 toc16
TA = +25°C
0
TA = -40°C
OUTPUT IP3 vs. OUTPUT POWER
OUTPUT IP3 vs. ATTENUATION
50
TA = -40°C
30
RF FREQUENCY (MHz)
RF FREQUENCY (MHz)
45
TA = +85°C
35
20
800
1000
40
25
36
36
1000
MAX2056 toc15
40
OUTPUT IP3 (dBm)
40
950
INPUT IP3 vs. ATTENUATION
OUTPUT IP3 vs. FREQUENCY
MAX2056 toc14
TA = -40°C
900
RF FREQUENCY (MHz)
41
MAX2056 toc13
41
800
850
RF FREQUENCY (MHz)
RF FREQUENCY (MHz)
38
900
MAX2056 toc18
700 800 900 1000 1100 1200 1300 1400 1500
OUTPUT IP3 (dBm)
MAX2056 toc12
MAX2056 toc11
6
MAXIMUM GAIN
20
OUTPUT IP3 (dBm)
TA = +25°C
7
NOISE FIGURE (dB)
45
TA = +85°C
6
50
NOISE FIGURE (dB)
REVERSE ISOLATION (dB)
7
MAX2056 toc10
21dB GAIN REDUCTION
55
25
NOISE FIGURE vs. RF FREQUENCY
NOISE FIGURE vs. RF FREQUENCY
60
-6
-3
0
3
6
9
OUTPUT POWER PER TONE (dBm)
12
800
850
900
950
1000
RF FREQUENCY (MHz)
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5
MAX2056
Typical Operating Characteristics (continued)
Typical Operating Characteristics (continued)
One Attenuator Configuration
(Typical Application Circuit with one attenuator connected, VCC = +5.0V, R1 = 1.2kΩ, R2 = 3.92kΩ, fIN = 900MHz maximum gain
setting, POUT = +5dBm, linearity measured at POUT = +5dBm/tone, TA = +25°C, unless otherwise noted.)
60
55
VCC = 5.25V
50
55
TA = -40°C
50
TA = +25°C
45
40
45
900
950
1000
5
10
15
OUTPUT P1dB vs. RF FREQUENCY
TA = +85°C
45
20
25
0
5
10
OUTPUT P1dB vs. RF FREQUENCY
MAX2056 toc22
TA = -40°C
24
23
TA = +25°C
TA = +85°C
21
VCC = 5.25V
25
24
23
VCC = 5.00V
22
VCC = 4.75V
21
20
20
800
850
900
950
RF FREQUENCY (MHz)
1000
800
15
ATTENUATION (dB)
26
OUTPUT P1dB (dBm)
OUTPUT P1dB (dBm)
50
ATTENUATION (dB)
26
22
55
35
0
RF FREQUENCY (MHz)
25
TA = +25°C
MAX2056 toc23
850
TA = -40°C
40
35
800
6
60
OUTPUT IP2 (dBm)
TA = +85°C
60
INPUT IP2 (dBm)
VCC = 5.00V
VCC = 4.75V
OUTPUT IP2 vs. ATTENUATION
65
MAX2056 toc20
MAX2056 toc19
65
INPUT IP2 vs. ATTENUATION
65
MAX2056 toc21
OUTPUT IP2 vs. RF FREQUENCY
70
OUTPUT IP2 (dBm)
MAX2056
800MHz to 1000MHz Variable-Gain
Amplifier with Analog Gain Control
850
900
950
1000
RF FREQUENCY (MHz)
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20
25
800MHz to 1000MHz Variable-Gain
Amplifier with Analog Gain Control
Two Attenuator Configuration
15
20
TA = +85°C
TA = +25°C
30
MAX2056 toc25
15
TA = -40°C
TA = +85°C
-25
30
40
700 800 900 1000 1100 1200 1300 1400 1500
-35
700 800 900 1000 1100 1200 1300 1400 1500
RF FREQUENCY (MHz)
RF FREQUENCY (MHz)
GAIN vs. RF FREQUENCY
REVERSE ISOLATION
vs. RF FREQUENCY
TA = +85°C
ISOLATION (dB)
TA = -40°C
13
TA = +25°C
11
TA = +85°C
30
TA = -40°C
1.5
2.0
2.5
3.0
VCNTL (V)
3.5
0
TA = +25°C
25
5
INPUT RETURN LOSS (dB)
15
1.0
4.0
INPUT RETURN LOSS
vs. RF FREQUENCY
35
MAX2056 toc27
17
TA = +85°C
-5
-15
20
25
35
9
10
MAXIMUM GAIN
15
20
25
42dB GAIN REDUCTION
30
20
7
700 800 900 1000 1100 1200 1300 1400 1500
700
900
RF FREQUENCY (MHz)
1100
1500
700 800 900 1000 1100 1200 1300 1400 1500
RF FREQUENCY (MHz)
5
MAXIMUM GAIN
15
MAX2056 toc31
GAIN vs. RF FREQUENCY
25
MAX2056 toc30
0
5
10
MAXIMUM GAIN
15
20
25
1300
RF FREQUENCY (MHz)
OUTPUT RETURN LOSS
vs. RF FREQUENCY
OUTPUT RETURN LOSS (dB)
GAIN (dB)
TA = +25°C
MAX2056 toc28
25
TA = +25°C
5
10
MAX2056 toc29
TA = -40°C
TA = -40°C
15
GAIN (dB)
10
5
GAIN (dB)
INPUT RETURN LOSS (dB)
5
0
OUTPUT RETURN LOSS (dB)
MAX2056 toc24
0
MAX2056 toc26
(Typical Application Circuit with two attenuators connected, VCC = +5.0V, R1 = 1.2kΩ, R2 = 3.92kΩ, fIN = 900MHz maximum gain
setting, POUT = +5dBm, linearity measured at POUT = +5dBm/tone, TA = +25°C, unless otherwise noted.)
OUTPUT RETURN LOSS
INPUT RETURN LOSS
vs. RF FREQUENCY
GAIN vs. VCNTL
vs. RF FREQUENCY
-5
-15
-25
42dB GAIN REDUCTION
-35
44dB GAIN REDUCTION
30
-45
700 800 900 1000 1100 1200 1300 1400 1500
700 800 900 1000 1100 1200 1300 1400 1500
RF FREQUENCY (MHz)
RF FREQUENCY (MHz)
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7
MAX2056
Typical Operating Characteristics
Typical Operating Characteristics (continued)
Two Attenuator Configuration
(Typical Application Circuit with two attenuators connected, VCC = +5.0V, R1 = 1.2kΩ, R2 = 3.92kΩ, fIN = 900MHz maximum gain
setting, POUT = +5dBm, linearity measured at POUT = +5dBm/tone, TA = +25°C, unless otherwise noted.)
REVERSE ISOLATION
vs. RF FREQUENCY
NOISE FIGURE (dB)
50
40
7
TA = +25°C
6
5
30
TA = -40°C
MAXIMUM GAIN
20
4
700
900
1100
1300
1500
800
RF FREQUENCY (MHz)
1000
OUTPUT IP2 vs. RF FREQUENCY
60
OUTPUT IP2 (dBm)
39
TA = +25°C
38
950
65
MAX2056 toc34
TA = -40°C
40
900
RF FREQUENCY (MHz)
OUTPUT IP3 vs. RF FREQUENCY
41
850
TA = -40°C
MAX2056 toc35
REVERSE ISOLATION (dB)
60
TA = +85°C
8
MAX2056 toc33
42dB GAIN REDUCTION
70
NOISE FIGURE vs. RF FREQUENCY
9
MAX2056 toc32
80
OUTPUT IP3 (dBm)
MAX2056
800MHz to 1000MHz Variable-Gain
Amplifier with Analog Gain Control
55
TA = +25°C
50
TA = +85°C
TA = +85°C
37
45
36
40
800
850
900
950
RF FREQUENCY (MHz)
8
1000
800
850
900
950
1000
RF FREQUENCY (MHz)
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800MHz to 1000MHz Variable-Gain
Amplifier with Analog Gain Control
PIN
NAME
FUNCTION
1, 3, 4, 6, 7,
9, 10, 12, 14,
18, 19,
21–24, 27,
28, 30, 31,
33, 34, 36
GND
2
OUT_A
5, 13, 16, 25,
32
VCC
Power Supply. Bypass each pin to GND with capacitors as shown in the Typical Application Circuit.
Place capacitors as close to the pin as possible.
8
IN_A
Second-Attenuator Input. Internally matched to 50Ω over the operating frequency band. Connect to a
50Ω RF source through a DC-blocking capacitor if greater than 22dB of gain-control range is
required. No connection is required if the second attenuator is not used.
11
VCNTL
Analog Gain-Control Input. Limit voltages applied to this pin to a 1V to 4.5V range when VCC is
present to ensure device reliability.
15
RSET1
First-Stage Amplifier Bias-Current Setting. Connect to GND through a 1.2kΩ resistor.
17
RSET2
Second-Stage Amplifier Bias-Current Setting. Connect to GND through a 3.92kΩ resistor.
20
OUT
RF Output. Internally matched to 50Ω over the operating frequency band. Requires a DC-blocking
capacitor.
26
AMP_IN
Amplifier Input. Internally matched to 50Ω over the operating frequency band. Connect to ATTN_OUT
through a DC-blocking capacitor.
29
ATTN_OUT
Attenuator Output. Internally matched to 50Ω over the operating frequency band. Connect to AMP_IN
through a DC-blocking capacitor.
35
IN
RF Input. Internally matched to 50Ω over the operating frequency band. Connect to a 50Ω RF source
through a DC-blocking capacitor if the second attenuator is not used.
Exposed
Paddle
GND
Ground. Connect to the board’s ground plane using low-inductance layout techniques.
Second-Attenuator Output. Internally matched to 50Ω over the operating frequency band. Connect to
IN through a DC-blocking capacitor if greater than 22dB of gain-control range is required. No
connection is required if the second attenuator is not used.
Exposed Paddle Ground Plane. This paddle affects RF performance and provides heat dissipation.
This paddle MUST be soldered evenly to the board’s ground plane for proper operation.
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9
MAX2056
Pin Description
MAX2056
800MHz to 1000MHz Variable-Gain
Amplifier with Analog Gain Control
VCC
GND
OUT_A
35
34
32
33
31
30
29
GND
GND
GND
VCC
GND
GND
IN
GND
36
ATTN_OUT
C4
C3
RF INPUT*
C5
28
1
27
2
26
GND
AMP_IN
VCC
EP
IN_A
GND
22
6
ATTENUATION
CONTROL
CIRCUITRY
7
21
8
20
9
19
11
VCNTL
GND
10
12
13
14
15
16
17
VCC
C6
C13
GND
GND
GND
GND
C7
OUT
RF
OUTPUT
GND
18
GND
GND
C1
23
RSET2
GND
5
VCC
VCC
24
RSET1
C2
4
GND
GND
MAX2056
VCC
VCC
25
GND
GND
3
R1
VGC
+
-
VCC
C10
C15
VCC
C9
C8
R2
C14
*NOTE: CONNECT THE INPUT ACCORDING TO THE SOLID BOLD LINE IF ONE ATTENUATOR
IS USED. CONNECT THE INPUT ACCORDING TO THE BROKEN LINE IF TWO ATTENUATORS ARE USED.
Figure 1. Typical Application Circuit
Detailed Description
The MAX2056 general-purpose, high-performance VGA
with analog gain control is designed to interface with
50Ω systems operating in the 800MHz to 1000MHz frequency range.
The MAX2056 integrates two attenuators to provide
22dB or 44dB of precision analog gain control, as well
10
as a two-stage amplifier that has been optimized to
provide high gain, high IP3, low noise figure, and lowpower consumption. The bias current of each amplifier
stage can be adjusted by individual external resistors
to further reduce power consumption for applications
that do not require high linearity.
______________________________________________________________________________________
www.BDTIC.com/maxim
800MHz to 1000MHz Variable-Gain
Amplifier with Analog Gain Control
DESIGNATION
VALUE
C1, C3, C5, C10
47pF
C2, C4, C6, C8, C9
TYPE
Microwave capacitors (0402)
1000pF Microwave capacitors (0402)
C7
3.9pF
Microwave capacitor (0402)
C13, C14, C15
0.1µF
Microwave capacitors (0603)
R1
1.2kΩ
±1% resistor (0402)
R2
3.92kΩ
±1% resistor (0402)
Applications Information
Analog Attenuation Control
A single input voltage at the VCNTL pin adjusts the gain
of the MAX2056. Up to 22dB of gain-control range is
provided through a single attenuator. At the maximum
gain setting, each attenuator’s insertion loss is approximately 1.7dB. With the single attenuator at the maximum gain setting, the device provides a nominal
15.5dB of cascaded gain and 4.5dB of cascaded noise
figure.
If a larger gain-control range is desired, a second onchip attenuator can be connected in the signal path to
provide an additional 22dB of gain-control range. With
the second attenuator connected at the maximum gain
setting, the device typically exhibits 13.8dB of cascaded gain. Note that the VCNTL pin simultaneously adjusts
both on-chip attenuators. The VCNTL input voltage drives a high-impedance load (>250kΩ). It is suggested
that a current-limiting resistor be included in series with
this connection to limit the input current to less than
40mA should the control voltage be applied when VCC
is not present. A series resistor of greater than 200Ω
will provide complete protection for 5V control voltage
ranges. Limit VCNTL input voltages to a 1.0V to 4.5V
range when VCC is present to ensure the reliability
of the device.
Amplifier Bias Current
The MAX2056 integrates a two-stage amplifier to simultaneously provide high gain and high IP3. Optimal per-
formance is obtained when R1 and R2 are equal to
1.2kΩ and 3.92kΩ, respectively. The typical supply current is 136mA and the typical output IP3 is 39dBm
under these conditions.
Increasing R1 and R2 from the nominal values of 1.2kΩ
and 3.92kΩ reduces the bias current of each amplifier
stage, which reduces the total power consumption and
IP3 of the device. This feature can be utilized to further
decrease power consumption for applications that do
not require high IP3.
Layout Considerations
A properly designed PC board is an essential part of
any RF/microwave circuit. Keep RF signal lines as short
as possible to reduce losses, radiation, and inductance. For best performance, route the ground-pin
traces directly to the exposed pad underneath the
package. This pad MUST be connected to the ground
plane of the board by using multiple vias under the
device to provide the best RF and thermal conduction
path. Solder the exposed pad on the bottom of the
device package to a PC board exposed pad.
Power-Supply Bypassing
Proper voltage-supply bypassing is essential for highfrequency circuit stability. Bypass each VCC pin with
capacitors placed as close to the device as possible.
Place the smallest capacitor closest to the device. Refer
to the MAX2056 evaluation kit data sheet for more details.
Exposed Paddle RF and Thermal
Considerations
The EP of the MAX2056’s 36-pin thin QFN-EP package
provides a low-thermal-resistance path to the die. It is
important that the PC board on which the IC is mounted
be designed to conduct heat from this contact. In addition, the EP provides a low-inductance RF ground path
for the device.
The EP MUST be soldered to a ground plane on the PC
board either directly or through an array of plated via
holes. Soldering the pad to ground is also critical for
efficient heat transfer. Use a solid ground plane wherever possible.
______________________________________________________________________________________
www.BDTIC.com/maxim
11
MAX2056
Table 1. Typical Application Circuit
Components Values
GND
1
OUT_A
2
GND
3
GND
IN
GND
GND
VCC
GND
GND
ATTN_OUT
GND
Pin Configuration/
Functional Diagram
36
35
34
33
32
31
30
29
28
Chip Information
TRANSISTOR COUNT: 5723
PROCESS: BiCMOS
Package Information
For the latest package outline information, go to
www.maxim-ic.com/packages.
27 GND
26 AMP_IN
EP
25 VCC
MAX2056
GND
4
24 GND
VCC
5
23 GND
GND
6
GND
22 GND
ATTENUATION
CONTROL
CIRCUITRY
7
21 GND
14
15
16
17
18
GND
13
RSET2
12
VCC
11
RSET1
10
GND
19 GND
VCC
GND 9
GND
20 OUT
VCNTL
IN_A 8
GND
MAX2056
800MHz to 1000MHz Variable-Gain
Amplifier with Analog Gain Control
Thin QFN
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
12 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2005 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products, Inc.
www.BDTIC.com/maxim