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19-3510; Rev 0; 1/05
KIT ATION EVALU E AILABL AV
1700MHz to 2500MHz Variable-Gain Amplifier with Analog Gain Control
General Description 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
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, cdma2000TM, 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 -40C to +85C temperature range.
Applications
DCS 1800/PCS 1900 2G and 2.5G EDGE BaseStation Transmitters and Power Amplifiers cdmaOneTM, 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.
MAX2057ETX+TD -40C to +85C PART MAX2057ETX MAX2057ETX-T MAX2057ETX+D
Ordering Information
TEMP RANGE -40C to +85C -40C to +85C -40C to +85C PIN-PACKAGE PKG CODE
36 Thin QFN-EP** T3666-2 6mm x 6mm 36 Thin QFN-EP** T3666-2 6mm x 6mm 36 Thin QFN-EP** T3666-2 6mm x 6mm 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 appear at end of data sheet.
________________________________________________________________ Maxim Integrated Products
1
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.
1700MHz to 2500MHz Variable-Gain Amplifier with Analog Gain Control MAX2057
ABSOLUTE MAXIMUM RATINGS
VCC to GND ...........................................................-0.3V to +5.5V VCNTL to GND (with VCC applied) .............................0V 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 JA (natural convection)...................................................35C/W JA (1m/s airflow) .............................................................31C/W JA (2.5m/s airflow) ..........................................................29C/W JC (junction to exposed paddle) ....................................10C/W Operating Temperature Range ...........................-40C to +85C Storage Temperature Range .............................-65C to +150C Junction Temperature ......................................................+150C Lead Temperature (soldering, 10s) .................................+300C
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 50, TA = -40C to +85C, unless otherwise noted. Typical values are at VCC = +5.0V, TA = +25C, unless otherwise noted.)
PARAMETER Supply Voltage Supply Current RSET1 Current RSET2 Current Gain-Control Voltage Range R1 = 1.2k, R2 = 2k (Note 1) R1 = 1.2k (Note 1) R1 = 2k (Note 1) (Note 2) 1.0 250 500 CONDITIONS MIN 4.75 TYP 5 180 1 0.6 4.5 MAX 5.25 230 UNITS V mA mA mA V k
Gain-Control Pin Input Resistance VCNTL = 1V to 4.5V
AC ELECTRICAL CHARACTERISTICS
(Typical Operating Circuit with one attenuator connected, VCC = +4.75V to +5.25V, TA = -40C to +85C, unless otherwise noted. Typical values are at VCC = +5.0V, R1 = 1.2k, R2 = 2k, POUT = +5dBm, fIN = 2100MHz, VCNTL = 1V, 50 system impedance, second attenuator is not connected, TA = +25C, unless otherwise noted.) (Note 3)
PARAMETER Frequency Range Gain TA = +25C VCNTL = 1V TA = +25C to -40C Maximum Gain Variation TA = +25C to +85C VCNTL = 1.8V VCNTL = 2.6V VCNTL = 3.5V VCNTL = 1V VCNTL = 1.8V VCNTL = 2.6V VCNTL = 3.5V Reverse Isolation Noise Figure Output 1dB Compression Point Output 2nd-Order Intercept Point Output 3rd-Order Intercept Point From maximum gain to 15dB attenuation, measured at f1 + f2 (Note 5) From maximum gain to 15dB attenuation (Note 5) (Note 4) CONDITIONS MIN 1700 13.5 15.5 +0.9 +0.41 +0.09 -0.16 -1 -0.56 -0.32 +0.1 37 6 +23.8 +64 +37 dB dB dBm dBm dBm dB TYP MAX 2500 17.5 UNITS MHz dB
2
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1700MHz to 2500MHz Variable-Gain Amplifier with Analog Gain Control
AC ELECTRICAL CHARACTERISTICS (continued)
(Typical Operating Circuit with one attenuator connected, VCC = +4.75V to +5.25V, TA = -40C to +85C, unless otherwise noted. Typical values are at VCC = +5.0V, R1 = 1.2k, R2 = 2k, POUT = +5dBm, fIN = 2100MHz, VCNTL = 1V, 50 system impedance, second attenuator is not connected, TA = +25C, unless otherwise noted.) (Note 3)
PARAMETER Output 3rd-Order Intercept Point Variation Over Temperature 2nd Harmonic 3rd Harmonic RF Gain-Control Range RF Gain-Control Slope Maximum RF Gain-Control Slope Gain Flatness Over 100MHz Bandwidth Attenuator Switching Time Attenuator Insertion Loss Input Return Loss Output Return Loss Group Delay Group Delay Flatness Over 100MHz Bandwidth Group Delay Change vs. Gain Control Insertion Phase Change vs. Gain Control TA = +25C to +85C TA = +25C to -40C From maximum gain to 15dB attenuation, POUT = +5dBm From maximum gain to 15dB attenuation, POUT = +5dBm fRF = 1.7GHz to 2.2GHz, VCNTL = 1V to 4.5V VCNTL = 1.8V to 3.5V Maximum slope vs. gain-control voltage Peak-to-peak for all settings 15dB attenuation change (Note 6) Second attenuator (IN_A, OUT_A) Entire band, all gain settings Entire band, all gain settings Input/output 50 lines de-embedded Peak to peak VCNTL = 1V to 4V VCNTL = 1V to 4V One attenuator Two attenuators 17 34 CONDITIONS MIN TYP -0.83 -0.6 -65 -83 20.7 42.4 -10 -15.2 0.5 500 2.2 18 15 300 20 -70 50 MAX UNITS dB dBc dBc dB dB/V dB/V dB ns dB dB dB ps ps ps degrees
MAX2057
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 = 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.
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1700MHz to 2500MHz Variable-Gain Amplifier with Analog Gain Control MAX2057
Typical Operating Characteristics
One Attenuator Configuration
(Typical Application Circuit with one attenuator connected, VCC = +5.0V, R1 = 1.2k, R2 = 2k, fIN = 2100MHz, maximum gain setting, POUT = +5dBm, linearity measured at POUT = +5dBm/tone, TA = +25C, unless otherwise noted.) SUPPLY CURRENT INPUT RETURN LOSS OUTPUT RETURN LOSS vs. SUPPLY VOLTAGE vs. RF FREQUENCY vs. RF FREQUENCY
MAX2057 toc01 MAX2057 toc02
TA = +85C 190 SUPPLY CURRENT (mA)
5 INPUT RETURN LOSS (dB) 10 15 20 25 30 35 40 TA = +25C TA = -40C TA = +85C
5 OUTPUT RETURN LOSS (dB) 10 15 20 25 30 35 40 TA = +85C TA = +25C TA = -40C
180 TA = +25C
170
160 TA = -40C 150 4.750 4.875 5.000 5.125 5.250
1500
1700
1900
2100
2300
2500
1500
1700
1900
2100
2300
2500
SUPPLY VOLTAGE (V)
RF FREQUENCY (MHz)
RF FREQUENCY (MHz)
GAIN vs. GAIN-CONTROL VOLTAGE
MAX2057 toc04
GAIN vs. RF FREQUENCY
TA = -40C 17
MAX2057 toc05
REVERSE ISOLATION vs. RF FREQUENCY
MAX2057 toc06
20 TA = -40C 15 10 GAIN (dB) 5 0 -5 -10 1.0 1.5 2.0 2.5 VCNTL (V) 3.0 3.5 TA = +25C
19
40 TA = +85C REVERSE ISOLATION (dB) 35 TA = +25C
GAIN (dB)
15
TA = +25C TA = +85C
TA = +85C
13
30
TA = -40C
11
9 4.0 1500 1700 1900 2100 2300 2500 RF FREQUENCY (MHz)
25 1500 1700 1900 2100 2300 2500 RF FREQUENCY (MHz)
INPUT RETURN LOSS vs. RF FREQUENCY
MAX2057 toc07
OUTPUT RETURN LOSS vs. RF FREQUENCY
MAX2057 toc08
GAIN vs. RF FREQUENCY
MAXIMUM GAIN
MAX2057 toc09
0 5 INPUT RETURN LOSS (dB) 10 15 20 25 30 35 40 1500 1700 1900 2100 2300 6dB GAIN REDUCTION 3dB GAIN REDUCTION 9dB, 12dB, 15dB, 18dB GAIN REDUCTION MAX GAIN
0 5 OUTPUT RETURN LOSS (dB) 10
20 15 10 GAIN (dB) 5 0 -5 -10 18dB GAIN REDUCTION
15 20 25 30 35 40 MAX GAIN, 3dB, 6dB, 9dB, 12dB, 15dB, AND 18dB GAIN REDUCTION
2500
1500
1700
1900
2100
2300
2500
1500
1700
1900
2100
2300
2500
RF FREQUENCY (MHz)
RF FREQUENCY (MHz)
RF FREQUENCY (MHz)
4
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MAX2057 toc03
200
0
0
1700MHz to 2500MHz Variable-Gain Amplifier with Analog Gain Control MAX2057
Typical Operating Characteristics (continued)
One Attenuator Configuration
(Typical Application Circuit with one attenuator connected, VCC = +5.0V, R1 = 1.2k, R2 = 2k, fIN = 2100MHz, maximum gain setting, POUT = +5dBm, linearity measured at POUT = +5dBm/tone, TA = +25C, unless otherwise noted.)
REVERSE ISOLATION vs. RF FREQUENCY
MAX2057 toc10
NOISE FIGURE vs. RF FREQUENCY
MAX2057 toc11
NOISE FIGURE vs. RF FREQUENCY
7.5 7.0 NOISE FIGURE (dB) VCC = 4.75V 6.5 6.0 5.5 VCC = 5.00V 5.0 VCC = 5.25V 4.5 4.0 2500 1500 1700 1900 2100 2300 2500
MAX2057 toc12
60 18dB GAIN REDUCTION 55 REVERSE ISOLATION (dB) 50
8.0 7.5 7.0 NOISE FIGURE (dB) 6.5 6.0 5.5 5.0 4.5 4.0 1500 1700 1900 TA = -40C 2100 2300 TA = +25C TA = +85C
8.0
45 40 35 MAXIMUM GAIN 30 25 20 1500 1700 1900 2100 2300 2500 RF FREQUENCY (MHz)
RF FREQUENCY (MHz)
RF FREQUENCY (MHz)
OUTPUT IP3 vs. RF FREQUENCY
MAX2057 toc13
OUTPUT IP3 vs. RF FREQUENCY
VCC = 5.25V 38 OUTPUT IP3 (dBm)
MAX2057 toc14
INPUT IP3 vs. ATTENUATION
MAX2057 toc15
40 TA = -40C
40
41 38 35 32 TA = +85C 29 26 TA = -40C TA = +25C
38 OUTPUT IP3 (dBm)
36
TA = +85C TA = +25C
36
VCC = 4.75V VCC = 5.00V
34
34
32
32 23
INPUT IP3 (dBm)
30 1500 1700 1900 2100 2300 2500 RF FREQUENCY (MHz)
30 1500 1700 1900 2100 2300 2500 RF FREQUENCY (MHz)
20 0 5 10 ATTENUATION (dB) 15 20
OUTPUT IP3 vs. ATTENUATION
MAX2057 toc16
OUTPUT IP3 vs. OUTPUT POWER
MAX2057 toc17
OUTPUT IP2 vs. RF FREQUENCY
MAX2057 toc18
40 TA = +25C 38 OUTPUT IP3 (dBm)
38 37 OUTPUT IP3 (dBm) 36 35 34 33 32
75 70 OUTPUT IP2 (dBm) 65 60 TA = +25C 55 50 45 TA = -40C TA = +85C
36 TA = +85C TA = -40C
34
32
30 0 5 10 ATTENUATION (dB) 15 20
-6
-3
0
3
6
9
12
1500
1700
1900
2100
2300
2500
OUTPUT POWER PER TONE (dBm)
RF FREQUENCY (MHz)
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1700MHz to 2500MHz Variable-Gain Amplifier with Analog Gain Control MAX2057
Typical Operating Characteristics (continued)
One Attenuator Configuration
(Typical Application Circuit with one attenuator connected, VCC = +5.0V, R1 = 1.2k, R2 = 2k, fIN = 2100MHz, maximum gain setting, POUT = +5dBm, linearity measured at POUT = +5dBm/tone, TA = +25C, unless otherwise noted.)
OUTPUT IP2 vs. RF FREQUENCY
MAX2057 toc19
INPUT IP2 vs. ATTENUATION
MAX2057 toc20
OUTPUT IP2 vs. ATTENUATION
TA = +85C OUTPUT IP2 (dBm)
MAX2057 toc21
75 70 OUTPUT IP2 (dBm) 65 60 55 50 45 1500 1700 1900 2100 2300 VCC = 5.25V VCC = 5.00V VCC = 4.75V
70 65 TA = +85C INPUT IP2 (dBm) 60 55 50 45 40 TA = +25C TA = -40C
70
65 TA = +25C
60
TA = -40C
55 0 5 10 ATTENUATION (dB) 15 20 0 5 10 ATTENUATION (dB) 15 20
2500
RF FREQUENCY (MHz)
OUTPUT P1dB vs. RF FREQUENCY
MAX2057 toc22
OUTPUT P1dB vs. RF FREQUENCY
VCC = 5.25V 25 OUTPUT P1dB (dBm) 24 23 VCC = 4.75V 22 21 20 VCC = 5.00V
MAX2057 toc23
26 25 OUTPUT P1dB (dBm) 24 23 22 21 20 1500 1700 1900 2100 2300 TA = +85C TA = -40C TA = +25C
26
2500
1500
1700
1900
2100
2300
2500
RF FREQUENCY (MHz)
RF FREQUENCY (MHz)
6
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1700MHz to 2500MHz Variable-Gain Amplifier with Analog Gain Control MAX2057
Typical Operating Characteristics
Two Attenuator Configuration
(Typical Application Circuit with two attenuators connected, VCC = +5.0V, R1 = 1.2k, R2 = 2k, fIN = 2100MHz, maximum gain setting, POUT = +5dBm, linearity measured at POUT = +5dBm/tone, TA = +25C, unless otherwise noted.)
INPUT RETURN LOSS vs. RF FREQUENCY
MAX2057 toc24
OUTPUT RETURN LOSS vs. RF FREQUENCY
5 OUTPUT RETURN LOSS (dB) 10 15 20 25 30 35 40 TA = +25C TA = +85C TA = -40C
MAX2057 toc25
0 5 INPUT RETURN LOSS (dB) 10 15 20 25 30 35 40 1500 1700 1900 2100 2300 TA = +85C TA = +25C TA = -40C
0
2500
1500
1700
1900
2100
2300
2500
RF FREQUENCY (MHz)
RF FREQUENCY (MHz)
GAIN vs. GAIN-CONTROL VOLTAGE
MAX2057 toc26
GAIN vs. RF FREQUENCY
MAX2057 toc27
15 TA = -40C
17 TA = -40C
5
TA = +25C TA = +85C
15
GAIN (dB)
-5
GAIN (dB)
13 TA = +25C 11 TA = +85C
-15
-25
9
-35 1.0 1.5 2.0 2.5 VCNTL (V) 3.0 3.5 4.0
7 1500 1700 1900 2100 2300 2500 RF FREQUENCY (MHz)
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1700MHz to 2500MHz Variable-Gain Amplifier with Analog Gain Control MAX2057
Typical Operating Characteristics (continued)
Two Attenuator Configuration
(Typical Application Circuit with two attenuators connected, VCC = +5.0V, R1 = 1.2k, R2 = 2k, fIN = 2100MHz, maximum gain setting, POUT = +5dBm, linearity measured at POUT = +5dBm/tone, TA = +25C, unless otherwise noted.)
REVERSE ISOLATION vs. RF FREQUENCY
MAX2057 toc28
INPUT RETURN LOSS vs. RF FREQUENCY
MAX2057 toc29
OUTPUT RETURN LOSS vs. RF FREQUENCY
5 OUTPUT RETURN LOSS (dB) 10 15 20 25 30 35 40 2500 1500 1700 1900 2100 2300 2500 6dB, 12dB, 18dB, 24dB, 30dB GAIN REDUCTION MAXIMUM GAIN
MAX2057 toc30
45
0 5 INPUT RETURN LOSS (dB) 10 15 20 25 30 35 12dB, 18dB, 24dB, 30dB GAIN REDUCTION MAXIMUM GAIN 6dB GAIN REDUCTION
0
REVERSE ISOLATION (dB)
TA = +85C 40
TA = -40C 35 TA = +25C
30 1500 1700 1900 2100 2300 2500 RF FREQUENCY (MHz)
40 1500 1700 1900 2100 2300 RF FREQUENCY (MHz)
RF FREQUENCY (MHz)
GAIN vs. RF FREQUENCY
MAX2057 toc31
REVERSE ISOLATION vs. RF FREQUENCY
MAX2057 toc32
NOISE FIGURE vs. RF FREQUENCY
10.5 10.0 NOISE FIGURE (dB) 9.5 9.0 8.5 8.0 7.5 TA = +25C TA = +85C
MAX2057 toc33
20 15 10 5 GAIN (dB) 0 -5 -10 -15 -20 -25 1500 1700 1900
MAXIMUM GAIN
80 70 REVERSE ISOLATION (dB) 60 50 40 30 MAXIMUM GAIN
11.0
30dB GAIN REDUCTION
7.0 6.5 TA = -40C 1500 1700 1900 2100 2300 2500
30dB GAIN REDUCTION 20 2100 2300 2500 1500 1700 1900 2100 2300 2500 RF FREQUENCY (MHz) RF FREQUENCY (MHz)
6.0 RF FREQUENCY (MHz)
OUTPUT IP3 vs. RF FREQUENCY
MAX2057 toc34
OUTPUT IP2 vs. RF FREQUENCY
TA = +85C 70 OUTPUT IP2 (dBm) 65 60 55 50 45 TA = -40C TA = +25C
MAX2057 toc35
40 TA = +25C
75
38 OUTPUT IP3 (dBm)
36
TA = -40C TA = +85C
34
32
30 1500 1700 1900 2100 2300 2500 RF FREQUENCY (MHz)
1500
1700
1900
2100
2300
2500
RF FREQUENCY (MHz)
8
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1700MHz to 2500MHz Variable-Gain Amplifier with Analog Gain Control
Pin Description
PIN 1, 3, 4, 6, 7, 9, 10, 12, 14, 18, 19, 21-24, 27, 28, 30, 31, 33, 34, 36 2 5, 13, 16, 25, 32 8 NAME FUNCTION
MAX2057
GND
Ground. Connect to the board's ground plane using low-inductance layout techniques.
OUT_A
Second-Attenuator Output. Internally matched to 50 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. 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. Second-Attenuator Input. Internally matched to 50 over the operating frequency band. Connect to a 50 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. 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. First-Stage Amplifier Bias-Current Setting. Connect to GND through a 1.2k resistor. Second-Stage Amplifier Bias-Current Setting. Connect to GND through a 2k resistor. RF Output. Internally matched to 50 over the operating frequency band. Requires a DC-blocking capacitor and a shunt-matching capacitor. Amplifier Input. Internally matched to 50 over the operating frequency band. Connect to ATTN_OUT through a DC-blocking capacitor. Attenuator Output. Internally matched to 50 over the operating frequency band. Connect to AMP_IN through a DC-blocking capacitor. RF Input. Internally matched to 50 over the operating frequency band. Connect to a 50 RF source through a DC-blocking capacitor 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.
VCC
IN_A
11 15 17 20 26 29 35 Exposed Paddle
VCNTL RSET1 RSET2 OUT AMP_IN ATTN_OUT IN GND
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1700MHz to 2500MHz Variable-Gain Amplifier with Analog Gain Control MAX2057
VCC
RF INPUT*
C3
C4
ATTN_OUT
GND
GND
GND
GND
GND
GND
VCC
IN
36 1 2 3
35
34
33
32
31
30
29
28 27 26
C5
GND OUT_A GND VCC GND VCC GND GND IN_A GND
GND AMP_IN VCC GND GND GND GND OUT GND 0.06in LONG FR4 50 TRANSMISSION LINE C17
EP MAX2057
VCC C13
25 24 23 22
C6
4 5 6 7 8 9 10 GND 11 VCNTL 12 GND 13 VCC 14 GND 15 RSET1 16 VCC 17 RSET2 18 GND ATTENUATION CONTROL CIRCUITRY
C2
21 20 19
C1
C7
RF OUTPUT
R1 VGC + C10 VCC VCC R2
C15
C9
C8
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 MAX2057 general-purpose, high-performance VGA with analog gain control is designed to interface with 50 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
10
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.
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1700MHz to 2500MHz Variable-Gain Amplifier with Analog Gain Control
Table 1. Typical Application Circuit Component Values
DESIGNATION C1, C3, C5, C7, C10 C2, C4, C6, C8, C9 C13, C14, C15 C17 R1 R2 VALUE 22pF 1000pF 0.1F 0.75pF 1.2k 2k TYPE Microwave capacitors (0402) Microwave capacitors (0402) Microwave capacitors (0603) Microwave capacitor (0402) 1% resistor (0402) 1% resistor (0402)
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 1.2k and 2k, respectively. The typical supply current is 180mA and the typical output IP3 is 37dBm under these conditions. Increasing R1 and R2 from the nominal values of 1.2k and 2k 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.
MAX2057
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.
Applications Information
Analog Attenuation Control
A single input voltage at the VCNTL 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 VCNTL pin simultaneously adjusts both on-chip attenuators. The VCNTL input voltage drives a high-impedance load (>250k). 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 200 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.
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 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.
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11
1700MHz to 2500MHz Variable-Gain Amplifier with Analog Gain Control MAX2057
Pin Configuration/ Functional Diagram
ATTN_OUT GND GND GND GND GND GND VCC
Chip Information
TRANSISTOR COUNT: 5191 PROCESS: BiCMOS
Package Information
27 GND 26 AMP_IN
IN
36 GND OUT_A GND GND VCC GND GND 1 2 3
35
34
33
32
31
30
29
28
For the latest package outline information, go to www.maxim-ic.com/packages.
EP 25 VCC MAX2057 24 GND 23 GND 22 GND ATTENUATION CONTROL CIRCUITRY 21 GND 20 OUT 19 GND 10 GND 11 VCNTL 12 GND 13 VCC 14 GND 15 RSET1 16 VCC 17 RSET2 18 GND
4 5 6 7
IN_A 8 GND 9
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 (c) 2005 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products, Inc.

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