General Description
The MAX2057 general-purpose, high-performance variable-gain amplifier (VGA) is designed to operate in the
1700MHz to 2500MHz frequency range*. This device
features 15.5dB of gain, 6dB of noise figure, and an output 1dB compression point of 23.8dBm. The MAX2057
also provides an exceptionally high OIP3 level of
37dBm, which is maintained over the entire attenuation
range. In addition, the on-chip analog attenuators yield
infinite control and high attenuation accuracy over
selectable 21dB or 42dB control ranges. Each of these
features makes the MAX2057 an ideal VGA for
DCS/PCS, cdma2000™, W-CDMA, and PHS/PAS transmitter and power amplifier AGC circuits.
The MAX2057 is pin compatible with the MAX2056
800MHz to 1000MHz VGA, making this family of amplifiers ideal for applications where a common PC board
layout is used for both frequency bands.
The MAX2057 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 paddle. Electrical
performance is guaranteed over the extended -40°C to
+85°C temperature range.
Applications
DCS 1800/PCS 1900 2G and 2.5G EDGE BaseStation Transmitters and Power Amplifiers
cdmaOne™, cdma2000, Base-Station
Transmitters and Power Amplifiers
UMTS/W-CDMA and Other 3G Base-Station
Transmitters and Power Amplifiers
PHS/PAS 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.
Features
♦ 1700MHz to 2500MHz RF Frequency Range*
♦ 37dBm Constant OIP3 (Over All Gain Settings)
♦ 23.8dBm Output 1dB Compression Point
♦ 15.5dB Typical Gain at Maximum Gain Setting
♦ 0.5dB Gain Flatness Over 100MHz Bandwidth
♦ 6dB Noise Figure at Maximum Gain Setting (Using
1 Attenuator)
♦ Two Gain-Control Ranges: 21dB and 42dB
♦ Analog Gain Control
♦ Single +5V Supply Voltage
♦ Pin Compatible with MAX2056, 800MHz to
1000MHz 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.
MAX2057
1700MHz to 2500MHz Variable-Gain
Amplifier with Analog Gain Control
________________________________________________________________ Maxim Integrated Products 1
Ordering Information
19-3510; Rev 0; 1/05
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.
EVALUATION KIT
AVAILABLE
PART
TEMP RANGE
PIN-PACKAGE
PKG
CODE
M AX 2057E TX
6mm x 6mm
T3666-2
M AX 2057E TX - T
6mm x 6mm
T3666-2
M AX 2057E TX + D
6mm x 6mm
T3666-2
M AX 2057E TX + TD
6mm x 6mm
T3666-2
**EP = Exposed paddle.
+ = Lead (Pb) free.
D = Dry pack.
-T = Tape-and-reel package.
Pin Configuration/Functional Diagram appear at end of data
sheet.
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
36 Thin QFN-EP**
36 Thin QFN-EP**
36 Thin QFN-EP**
36 Thin QFN-EP**
MAX2057
1700MHz to 2500MHz Variable-Gain
Amplifier with Analog Gain Control
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
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.
VCCto GND...........................................................-0.3V to +5.5V
V
CNTL
to GND (with VCCapplied) .............................0V to 4.75V
Current into V
CNTL
pin (VCCgrounded) .............................40mA
All Other Pins to GND.................................-0.3V to (V
CC
+ 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
θ
JA
(1m/s airflow) .............................................................31°C/W
θ
JA
(2.5m/s airflow) ..........................................................29°C/W
θ
JC
(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
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 V
CC
= +5.0V, TA= +25°C, unless otherwise noted.)
PARAMETER CONDITIONS
UNITS
Supply Voltage
5
V
Supply Current R1 = 1.2kΩ, R2 = 2kΩ (Note 1)
230 mA
R
SET1
Current R1 = 1.2kΩ (Note 1) 1 mA
R
SET2
Current R1 = 2kΩ (Note 1) 0.6 mA
Gain-Control Voltage Range (Note 2) 1.0 4.5 V
Gain-Control Pin Input Resistance
V
CNTL
= 1V to 4.5V
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 V
CC
= +5.0V, R1 = 1.2kΩ, R2 = 2kΩ, P
OUT
= +5dBm, fIN= 2100MHz, V
CNTL
= 1V, 50Ω system impedance,
second attenuator is not connected, T
A
= +25°C, unless otherwise noted.) (Note 3)
PARAMETER CONDITIONS
MIN
TYP
MAX
UNITS
Frequency Range
MHz
Gain TA = +25°C
dB
V
CNTL
= 1V
V
CNTL
= 1.8V
V
CNTL
= 2.6V
TA = +25°C to -40°C
V
CNTL
= 3.5V
V
CNTL
= 1V -1
V
CNTL
= 1.8V
V
CNTL
= 2.6V
Maximum Gain Variation
T
A
= +25°C to +85°C
V
CNTL
= 3.5V
dB
Reverse Isolation 37 dB
Noise Figure (Note 4) 6 dB
Output 1dB Compression Point
dBm
Output 2nd-Order Intercept Point
From maximum gain to 15dB attenuation, measured at f
1
+ f2 (Note 5)
dBm
Output 3rd-Order Intercept Point
From maximum gain to 15dB attenuation (Note 5)
dBm
MIN TYP MAX
4.75
180
5.25
250 500
1700 2500
13.5 15.5 17.5
+0.9
+0.41
+0.09
-0.16
-0.56
-0.32
+0.1
+23.8
+64
+37
MAX2057
1700MHz to 2500MHz Variable-Gain
Amplifier with Analog Gain Control
_______________________________________________________________________________________ 3
AC ELECTRICAL CHARACTERISTICS (continued)
(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 V
CC
= +5.0V, R1 = 1.2kΩ, R2 = 2kΩ, P
OUT
= +5dBm, fIN= 2100MHz, V
CNTL
= 1V, 50Ω system impedance,
second attenuator is not connected, T
A
= +25°C, unless otherwise noted.) (Note 3)
Note 1: Total supply current reduces as R1and R2are increased.
Note 2: Operating outside this range for extended periods may affect device reliability. Limit pin input current to 40mA when V
CC
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: f
1
= 2100MHz, f2= 2101MHz, +5dBm/tone at OUT.
Note 6: Switching time is measured from 50% of the control signal to when the RF output settles to ±1dB.
PARAMETER CONDITIONS
UNITS
TA = +25°C to +85°C
Output 3rd-Order Intercept Point
Variation Over Temperature
T
A
= +25°C to -40°C
dB
2nd Harmonic
-65 dBc
3rd Harmonic
-83 dBc
One attenuator 17
RF Gain-Control Range
f
RF
= 1.7GHz to 2.2GHz,
V
CNTL
= 1V to 4.5V
Two attenuators 34
dB
RF Gain-Control Slope V
CNTL
= 1.8V to 3.5V -10
dB/V
Maximum RF Gain-Control Slope
Maximum slope vs. gain-control voltage
dB/V
Gain Flatness Over
100MHz Bandwidth
Peak-to-peak for all settings 0.5 dB
Attenuator Switching Time 15dB attenuation change (Note 6)
ns
Attenuator Insertion Loss Second attenuator (IN_A, OUT_A) 2.2 dB
Input Return Loss Entire band, all gain settings 18 dB
Output Return Loss Entire band, all gain settings 15 dB
Group Delay Input/output 50Ω lines de-embedded
ps
Group Delay Flatness Over
100MHz Bandwidth
Peak to peak 20 ps
Group Delay Change vs. Gain
Control
V
CNTL
= 1V to 4V -70 ps
Insertion Phase Change vs. Gain
Control
V
CNTL
= 1V to 4V 50
degrees
From maximum gain to 15dB attenuation, P
From maximum gain to 15dB attenuation, P
OUT
OUT
= +5dBm
= +5dBm
MIN TYP MAX
-0.83
-0.6
20.7
42.4
-15.2
500
300
MAX2057
1700MHz to 2500MHz Variable-Gain
Amplifier with Analog Gain Control
4 _______________________________________________________________________________________
GAIN vs. GAIN-CONTROL VOLTAGE
MAX2057 toc04
V
CNTL
(V)
GAIN (dB)
3.53.02.52.01.5
-5
0
5
10
15
20
-10
1.0 4.0
TA = +25°C
TA = -40°C
TA = +85°C
GAIN vs. RF FREQUENCY
MAX2057 toc05
RF FREQUENCY (MHz)
GAIN (dB)
2300210019001700
11
13
15
17
19
9
1500 2500
TA = -40°C
TA = +25°C
TA = +85°C
REVERSE ISOLATION
vs. RF FREQUENCY
MAX2057 toc06
RF FREQUENCY (MHz)
REVERSE ISOLATION (dB)
2300210019001700
30
35
40
25
1500 2500
TA = +25°C
TA = +85°C
TA = -40°C
INPUT RETURN LOSS
vs. RF FREQUENCY
MAX2057 toc07
RF FREQUENCY (MHz)
INPUT RETURN LOSS (dB)
230021001700 1900
35
30
25
20
15
10
5
0
40
1500 2500
MAX GAIN
3dB GAIN REDUCTION
6dB GAIN REDUCTION
9dB, 12dB, 15dB, 18dB
GAIN REDUCTION
OUTPUT RETURN LOSS
vs. RF FREQUENCY
MAX2057 toc08
RF FREQUENCY (MHz)
OUTPUT RETURN LOSS (dB)
230021001700 1900
35
30
25
20
15
10
5
0
40
1500 2500
MAX GAIN, 3dB, 6dB, 9dB, 12dB,
15dB, AND 18dB GAIN REDUCTION
GAIN vs. RF FREQUENCY
MAX2057 toc09
RF FREQUENCY (MHz)
GAIN (dB)
2300210019001700
-5
0
5
10
15
20
-10
1500 2500
MAXIMUM GAIN
18dB GAIN REDUCTION
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX2057 toc01
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
5.1255.0004.875
160
170
180
190
200
150
4.750 5.250
TA = +85°C
TA = +25°C
TA = -40°C
INPUT RETURN LOSS
vs. RF FREQUENCY
MAX2057 toc02
RF FREQUENCY (MHz)
INPUT RETURN LOSS (dB)
230021001700 1900
35
30
25
20
15
10
5
0
40
1500 2500
TA = +85°C
TA = +25°C
TA = -40°C
OUTPUT RETURN LOSS
vs. RF FREQUENCY
MAX2057 toc03
RF FREQUENCY (MHz)
OUTPUT RETURN LOSS (dB)
230021001700 1900
35
30
25
20
15
10
5
0
40
1500 2500
TA = +25°C
TA = -40°C
TA = +85°C
Typical Operating Characteristics
One Attenuator Configuration
(Typical Application Circuit with one attenuator connected, VCC= +5.0V, R1 = 1.2kΩ, R2 = 2kΩ, fIN= 2100MHz, maximum gain
setting, P
OUT
= +5dBm, linearity measured at P
OUT
= +5dBm/tone, TA= +25°C, unless otherwise noted.)
MAX2057
1700MHz to 2500MHz Variable-Gain
Amplifier with Analog Gain Control
_______________________________________________________________________________________ 5
OUTPUT IP3 vs. RF FREQUENCY
MAX2057 toc13
RF FREQUENCY (MHz)
OUTPUT IP3 (dBm)
2300210019001700
32
34
36
38
40
30
1500 2500
TA = +85°C
TA = +25°C
TA = -40°C
OUTPUT IP3 vs. RF FREQUENCY
MAX2057 toc14
RF FREQUENCY (MHz)
OUTPUT IP3 (dBm)
2300210019001700
32
34
36
38
40
30
1500 2500
VCC = 4.75V
VCC = 5.25V
VCC = 5.00V
INPUT IP3 vs. ATTENUATION
MAX2057 toc15
ATTENUATION (dB)
INPUT IP3 (dBm)
15105
23
26
29
32
35
38
41
20
020
TA = +25°C
TA = +85°C
TA = -40°C
30
32
36
34
38
40
OUTPUT IP3 vs. ATTENUATION
MAX2057 toc16
ATTENUATION (dB)
OUTPUT IP3 (dBm)
01051520
TA = +25°C
TA = -40°C
TA = +85°C
32
34
33
36
35
37
38
-6 0 3-3 6 9 12
OUTPUT IP3 vs. OUTPUT POWER
MAX2057 toc17
OUTPUT POWER PER TONE (dBm)
OUTPUT IP3 (dBm)
OUTPUT IP2 vs. RF FREQUENCY
MAX2057 toc18
RF FREQUENCY (MHz)
OUTPUT IP2 (dBm)
2300210019001700
50
55
60
65
70
75
45
1500 2500
TA = +25°C
TA = -40°C
TA = +85°C
REVERSE ISOLATION
vs. RF FREQUENCY
MAX2057 toc10
RF FREQUENCY (MHz)
REVERSE ISOLATION (dB)
230021001700 1900
25
30
35
40
45
50
55
60
20
1500 2500
MAXIMUM GAIN
18dB GAIN REDUCTION
NOISE FIGURE vs. RF FREQUENCY
MAX2057 toc11
RF FREQUENCY (MHz)
NOISE FIGURE (dB)
230021001700 1900
4.5
5.0
5.5
6.0
6.5
7.0
7.5
8.0
4.0
1500 2500
TA = +85°C
TA = +25°C
TA = -40°C
NOISE FIGURE vs. RF FREQUENCY
MAX2057 toc12
RF FREQUENCY (MHz)
NOISE FIGURE (dB)
230021001700 1900
4.5
5.0
5.5
6.0
6.5
7.0
7.5
8.0
4.0
1500 2500
VCC = 4.75V
VCC = 5.25V
VCC = 5.00V
Typical Operating Characteristics (continued)
One Attenuator Configuration
(Typical Application Circuit with one attenuator connected, VCC= +5.0V, R1 = 1.2kΩ, R2 = 2kΩ, fIN= 2100MHz, maximum gain
setting, P
OUT
= +5dBm, linearity measured at P
OUT
= +5dBm/tone, TA= +25°C, unless otherwise noted.)
MAX2057
1700MHz to 2500MHz Variable-Gain
Amplifier with Analog Gain Control
6 _______________________________________________________________________________________
OUTPUT P1dB vs. RF FREQUENCY
MAX2057 toc22
RF FREQUENCY (MHz)
OUTPUT P1dB (dBm)
2300210019001700
21
22
23
24
25
26
20
1500 2500
TA = +25°C
TA = -40°C
TA = +85°C
OUTPUT P1dB vs. RF FREQUENCY
MAX2057 toc23
RF FREQUENCY (MHz)
OUTPUT P1dB (dBm)
2300210019001700
21
22
23
24
25
26
20
1500 2500
VCC = 4.75V
VCC = 5.25V
VCC = 5.00V
OUTPUT IP2 vs. RF FREQUENCY
MAX2057 toc19
RF FREQUENCY (MHz)
OUTPUT IP2 (dBm)
2300210019001700
50
55
60
65
70
75
45
1500 2500
VCC = 4.75V
VCC = 5.25V
VCC = 5.00V
INPUT IP2 vs. ATTENUATION
MAX2057 toc20
ATTENUATION (dB)
INPUT IP2 (dBm)
15105
45
50
55
60
65
70
40
020
TA = +25°C
TA = -40°C
TA = +85°C
55
60
65
70
051015 20
OUTPUT IP2 vs. ATTENUATION
MAX2057 toc21
ATTENUATION (dB)
OUTPUT IP2 (dBm)
TA = +25°C
TA = -40°C
TA = +85°C
Typical Operating Characteristics (continued)
One Attenuator Configuration
(Typical Application Circuit with one attenuator connected, VCC= +5.0V, R1 = 1.2kΩ, R2 = 2kΩ, fIN= 2100MHz, maximum gain
setting, P
OUT
= +5dBm, linearity measured at P
OUT
= +5dBm/tone, TA= +25°C, unless otherwise noted.)
MAX2057
1700MHz to 2500MHz Variable-Gain
Amplifier with Analog Gain Control
_______________________________________________________________________________________ 7
Typical Operating Characteristics
Two Attenuator Configuration
(Typical Application Circuit with two attenuators connected, VCC= +5.0V, R1 = 1.2kΩ, R2 = 2kΩ, fIN= 2100MHz, maximum gain
setting, P
OUT
= +5dBm, linearity measured at P
OUT
= +5dBm/tone, TA= +25°C, unless otherwise noted.)
INPUT RETURN LOSS
vs. RF FREQUENCY
MAX2057 toc24
RF FREQUENCY (MHz)
INPUT RETURN LOSS (dB)
230021001700 1900
35
30
25
20
15
10
5
0
40
1500 2500
TA = +25°C
TA = -40°C
TA = +85°C
OUTPUT RETURN LOSS
vs. RF FREQUENCY
MAX2057 toc25
RF FREQUENCY (MHz)
OUTPUT RETURN LOSS (dB)
230021001700 1900
35
30
25
20
15
10
5
0
40
1500 2500
TA = -40°C
TA = +25°C
TA = +85°C
GAIN vs. GAIN-CONTROL VOLTAGE
MAX2057 toc26
V
CNTL
(V)
GAIN (dB)
3.53.02.52.01.5
-25
-15
-5
5
15
-35
1.0 4.0
TA = -40°C
TA = +25°C
TA = +85°C
GAIN vs. RF FREQUENCY
MAX2057 toc27
RF FREQUENCY (MHz)
GAIN (dB)
2300210019001700
9
11
13
15
17
7
1500 2500
TA = -40°C
TA = +25°C
TA = +85°C
MAX2057
1700MHz to 2500MHz Variable-Gain
Amplifier with Analog Gain Control
8 _______________________________________________________________________________________
OUTPUT IP3 vs. RF FREQUENCY
MAX2057 toc34
RF FREQUENCY (MHz)
OUTPUT IP3 (dBm)
2300210019001700
32
34
36
38
40
30
1500 2500
TA = +85°C
TA = +25°C
TA = -40°C
OUTPUT IP2 vs. RF FREQUENCY
MAX2057 toc35
RF FREQUENCY (MHz)
OUTPUT IP2 (dBm)
2300210019001700
50
55
60
65
70
75
45
1500 2500
TA = +85°C
TA = +25°C
TA = -40°C
Typical Operating Characteristics (continued)
Two Attenuator Configuration
(Typical Application Circuit with two attenuators connected, VCC= +5.0V, R1 = 1.2kΩ, R2 = 2kΩ, fIN= 2100MHz, maximum gain
setting, P
OUT
= +5dBm, linearity measured at P
OUT
= +5dBm/tone, TA= +25°C, unless otherwise noted.)
REVERSE ISOLATION
vs. RF FREQUENCY
MAX2057 toc28
RF FREQUENCY (MHz)
REVERSE ISOLATION (dB)
2300210019001700
35
40
45
30
1500 2500
TA = +25°C
TA = +85°C
TA = -40°C
INPUT RETURN LOSS
vs. RF FREQUENCY
MAX2057 toc29
RF FREQUENCY (MHz)
INPUT RETURN LOSS (dB)
230021001700 1900
35
30
25
20
15
10
5
0
40
1500 2500
MAXIMUM GAIN
6dB GAIN REDUCTION
12dB, 18dB, 24dB, 30dB
GAIN REDUCTION
OUTPUT RETURN LOSS
vs. RF FREQUENCY
MAX2057 toc30
RF FREQUENCY (MHz)
OUTPUT RETURN LOSS (dB)
230021001700 1900
35
30
25
20
15
10
5
0
40
1500 2500
6dB, 12dB, 18dB, 24dB,
30dB GAIN REDUCTION
MAXIMUM GAIN
GAIN vs. RF FREQUENCY
MAX2057 toc31
RF FREQUENCY (MHz)
GAIN (dB)
2300210019001700
-20
-15
-5
-10
0
5
10
15
20
-25
1500 2500
MAXIMUM GAIN
30dB GAIN REDUCTION
REVERSE ISOLATION
vs. RF FREQUENCY
MAX2057 toc32
RF FREQUENCY (MHz)
REVERSE ISOLATION (dB)
230021001700 1900
30
40
50
60
70
80
20
1500 2500
30dB GAIN REDUCTION
MAXIMUM GAIN
NOISE FIGURE vs. RF FREQUENCY
MAX2057 toc33
RF FREQUENCY (MHz)
NOISE FIGURE (dB)
230021001700 1900
7.0
7.5
6.5
8.0
8.5
9.0
9.5
10.0
10.5
11.0
6.0
1500 2500
TA = +85°C
TA = +25°C
TA = -40°C
MAX2057
1700MHz to 2500MHz Variable-Gain
Amplifier with Analog Gain Control
_______________________________________________________________________________________ 9
Pin Description
PIN NAME FUNCTION
1, 3, 4, 6, 7,
9, 10, 12, 14,
18, 19,
21–24, 27,
28, 30, 31,
33, 34, 36
GND Ground. Connect to the board’s ground plane using low-inductance layout techniques.
2 OUT_A
Second-Attenuator Output. Internally matched to 50Ω over the operating frequency band. Connect to
IN through a DC-blocking capacitor if greater than 21dB of gain-control range is required. No
connection is required if the second attenuator is not used.
5, 13, 16, 25,
32
V
CC
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 21dB of gain-control range is
required. No connection is required if the second attenuator is not used.
11 V
CNTL
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 R
SET1
First-Stage Amplifier Bias-Current Setting. Connect to GND through a 1.2kΩ resistor.
17 R
SET2
Second-Stage Amplifier Bias-Current Setting. Connect to GND through a 2kΩ resistor.
20 OUT
RF Output. Internally matched to 50Ω over the operating frequency band. Requires a DC-blocking
capacitor and a shunt-matching 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
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
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.
ATTN_OUT
MAX2057
1700MHz to 2500MHz Variable-Gain
Amplifier with Analog Gain Control
10 ______________________________________________________________________________________
Detailed Description
The MAX2057 general-purpose, high-performance VGA
with analog gain control is designed to interface with
50Ω systems operating in the 1700MHz to 2500MHz
frequency range.
The MAX2057 integrates two attenuators to provide
21dB or 42dB of precision analog gain control, as well
as a two-stage amplifier that has been optimized to
provide high gain, high IP3, low noise figure, and low
power 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.
MAX2057
27
26
25
24
23
32 31 30 29 28
GND
V
GC
GND
GND
GND
OUT
GND
GND
GND
GND
GND
GND
GND
OUT_A
GND
IN_A
C4
C6
C10
C13
C5
RF
OUTPUT
R1
R2
C2
C1
C15 C9
C3
V
CC
V
CC
V
CC
C14C8
V
CC
RF INPUT*
*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.
V
CC
V
CC
GND
GNDINGND
GND
V
CC
GND
GND
ATTN_OUT
AMP_IN
GND
36 35 34 33
14 15 16 17 1810 11 12 13
22
20
21
19
5
4
3
2
9
8
7
6
1
+
-
ATTENUATION
CONTROL
CIRCUITRY
V
CC
V
CNTL
GND
V
CC
GND
R
SET1
V
CC
R
SET2
GND
C17
0.06in LONG FR4 50Ω
TRANSMISSION LINE
EP
C7
Figure 1. Typical Application Circuit
MAX2057
1700MHz to 2500MHz Variable-Gain
Amplifier with Analog Gain Control
______________________________________________________________________________________ 11
Applications Information
Analog Attenuation Control
A single input voltage at the V
CNTL
pin adjusts the gain
of the MAX2057. Up to 21dB of gain-control range is
provided through a single attenuator. At the maximum
gain setting, each attenuator’s insertion loss is approximately 2.2dB. With the single attenuator at the maximum
gain setting, the device provides a nominal 15.5dB of
cascaded gain and 6dB 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 21dB of gain-control range. With
the second attenuator connected at the maximum gain
setting, the device typically exhibits 13.3dB of cascaded gain. Note that the V
CNTL
pin simultaneously adjusts
both on-chip attenuators.
The V
CNTL
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 VCCis not present. A series resistor of greater than 200Ω will provide complete
protection for 5V control voltage ranges. Limit V
CNTL
input voltages to a 1.0V to 4.5V range when VCCis
present to ensure the reliability of the device.
Amplifier Bias Current
The MAX2057 integrates a two-stage amplifier to simultaneously provide high gain and high IP3. Optimal performance is obtained when R1 and R2 are equal to
1.2kΩ and 2kΩ, respectively. The typical supply current
is 180mA and the typical output IP3 is 37dBm under
these conditions.
Increasing R1and R2from the nominal values of 1.2kΩ
and 2kΩ 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 VCCpin with
capacitors placed as close to the device as possible.
Place the smallest capacitor closest to the device. Refer
to the MAX2057 evaluation kit data sheet for more details.
Exposed Paddle RF and Thermal
Considerations
The EP of the MAX2057’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.
DESIGNATION
TYPE
C1, C3, C5, C7, C10
22pF
Microwave capacitors
(0402)
C2, C4, C6, C8, C9
Microwave capacitors
(0402)
C13, C14, C15 0.1µF
Microwave capacitors
(0603)
C17
Microwave capacitor
(0402)
R1 1.2kΩ ±1% resistor (0402)
R2 2kΩ ±1% resistor (0402)
Table 1. Typical Application Circuit
Component Values
VALUE
1000pF
0.75pF
MAX2057
1700MHz to 2500MHz Variable-Gain
Amplifier with Analog Gain Control
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.
Pin Configuration/
Functional Diagram
MAX2057
27
26
25
24
23
32 31 30 29 28
GND
GND
GND
GND
OUT
GND
GND
GND
GND
GND
GND
OUT_A
GND
GND
IN_A
V
CC
V
CC
GND
GNDINGND
GND
V
CC
GND
GND
ATTN_OUT
AMP_IN
GND
V
CNTL
GND
V
CC
GND
R
SET1
V
CC
R
SET2
GND
36 35 34 33
14 15 16 17 1810 11 12 13
22
20
21
19
5
4
3
2
9
8
7
6
1
ATTENUATION
CONTROL
CIRCUITRY
EP
Chip Information
TRANSISTOR COUNT: 5191
PROCESS: BiCMOS
Package Information
For the latest package outline information, go to
www.maxim-ic.com/packages
.
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