General Description
The MAX3537/MAX3538 broadband RF variable-gain
amplifiers (VGA) are designed for digital and
OpenCable™ set-tops and televisions. These devices
feature a unique design that integrates a dual-band
(UHF and VHF) input and a low-noise, variable-gain
amplifier. The integrated RF VGA covers a 10MHz to
1GHz input frequency range and provides 22dB of
gain-control range.
The MAX3538 is intended for the most difficult signal
conditions where performance is critical. The external
pullup inductor improves IIP2 and IIP3 while also
increasing gain for better sensitivity. The MAX3537
does not need an external pullup inductor and is ideal
for low-power applications with less demanding receiv-
er distortion requirements such as smaller TVs using
indoor antennas.
The MAX3537/MAX3538 are specified for operation in
the 0°C to +85°C temperature range and are available
in 4mm x 4mm, 12-pin thin QFN packages with
exposed paddle (EP).
Applications
OpenCable Set-Top Boxes and Televisions
Digital Set-Top Boxes
Media Gateways
Digital Terrestrial Receivers
TV IF Strips
Features
♦Low-Noise VGA Eliminates PIN Attenuator
♦22dB Gain-Control Range
♦Low Noise Figure: 5dB at Maximum Gain Setting
♦High Linearity: +19dBm IIP3 (MAX3538) at
Maximum Gain Setting
♦Low Power Consumption: <200mW (MAX3537)
♦Available in a 4mm x 4mm, 12-Pin Thin QFN
Package
MAX3537/MAX3538
Broadband Variable-Gain Amplifiers
________________________________________________________________ Maxim Integrated Products 1
19-3445; Rev 0; 10/04
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
Ordering Information
PART TEMP
RANGE
PIN-PACKAGE
PKG
CODE
MAX3537UTC
0°C to +85°C 12 Thin QFN-EP*
T1244-3
MAX3538UTC
0°C to +85°C 12 Thin QFN-EP*
T1244-3
12 11 10
456
1
2RF_GND1
3
9
8
7UHF_SHUNT
LNAOUT
VCC
RFAGC
UHF_IN
RF_GND2
GND
VHF_IN
SEL_UHF
RBIAS
SHDN
MAX3537/3538
Pin Configuration/
Functional Diagram
OpenCable is a trademark of Cable Television Laboratories, Inc.
*EP = Exposed paddle.
MAX3537/MAX3538
Broadband Variable-Gain Amplifiers
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.
VCC to GND ...........................................................-0.3V to +5.5V
RFAGC, UHF_IN, SEL_UHF, VHF_IN, SHDN, RBIAS,
RF_GND1, RF_GND2, UHF_SHUNT
to GND....................................................-0.3V to (VCC + 0.3V)
LNAOUT Short-Circuit Duration..............................................10s
UHFIN, VHFIN Maximum RF Input Power.........................14dBm
Continuous Power Dissipation (TA= +70°C)
12-Pin Thin QFN (derate 16.9mW/°C
above +70°C)............................................................1349mW
Operating Temperature Range...............................0°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
DC ELECTRICAL CHARACTERISTICS
(MAX3537/MAX3538 EV kit, VCC = 4.75V to 5.25V, no RF signal applied, TA= 0°C to +85°C, unless otherwise noted. Typical values
are at VCC = 5V, RBIAS = 11.8kΩ(MAX3537) or 9.1kΩ(MAX3538), TA= +25°C, unless otherwise noted.) (Note 1)
PARAMETER CONDITIONS
MIN
TYP
MAX
UNITS
Supply Voltage
4.75 5.25
V
MAX3537 38
45.8
Operational mode MAX3538 48 58 mA
Supply Current
Standby mode (VENABLE = VSEL_UHF = 0.1V) 2 100 µA
RFAGC Input Bias Current VRFAGC = 1V and 3V -50
+50
µA
Maximum gain 3
RFAGC Control Voltage (Note 2)
Minimum gain 1 V
Input Logic-Level Low 0.3 x
VCC
V
Input Logic-Level High 0.7 x
VCC
V
AC ELECTRICAL CHARACTERISTICS (MAX3537)
(MAX3537 EV kit, VCC = 4.75V to 5.25V, TA= 0°C to +85°C, unless otherwise noted. Typical values are at VCC = 5V, RBIAS = 11.8kΩ,
TA= +25°C, unless otherwise noted.) (Note 1)
PARAMETER CONDITIONS
MIN
TYP
MAX
UNITS
Operating Frequency Range 50 878
MHz
Input Return Loss Diplex filter included, worst case across band, any gain
setting (Note 2) 4.3 8.5 dB
Input Power Range Per Channel
-35
+50
dBmV
Voltage Gain Maximum gain 7.7 9.6
12.7
dB
Linear Gain-Control Range Measured at 50MHz, difference between maximum and
minimum gain
19.2 23.1
dB
Gain Flatness From 50MHz to 878MHz, VRFAGC = 3V (Note 2) 2.8 dB
Noise Figure Maximum gain, diplexer loss included 5 dB
Maximum gain, VRFAGC = 3V (Notes 2, 3)
21.6
26
Input 2nd-Order Intercept Point Minimum gain, VRFAGC = 1V
42.5
48
dBm
CAUTION! ESD SENSITIVE DEVICE
MAX3537/MAX3538
Broadband Variable-Gain Amplifiers
_______________________________________________________________________________________ 3
AC ELECTRICAL CHARACTERISTICS (MAX3537) (continued)
(MAX3537 EV kit, VCC = 4.75V to 5.25V, TA= 0°C to +85°C, unless otherwise noted. Typical values are at VCC = 5V, RBIAS = 11.8kΩ,
TA= +25°C, unless otherwise noted.) (Note 1)
PARAMETER CONDITIONS
MIN
TYP
MAX
UNITS
Maximum gain, VRFAGC = 3V (Note 4)
12.7
17
Input 3rd-Order Intercept Point Minimum gain, VRFAGC = 1V (Note 2)
28.2
33
dBm
1dB Compression Point Maximum gain (Note 2) 0 1.9
dBm
Shutdown mode, 50MHz to 878MHz, RF input to RF
output 37
Isolation
Port to port 23
dBc
Output Return Loss Unbalanced 75Ω load 10 dB
AC ELECTRICAL CHARACTERISTICS (MAX3538)
(MAX3538 EV kit, VCC = 4.75V to 5.25V, TA= 0°C to +85°C, unless otherwise noted. Typical values are at VCC = 5V, RBIAS = 9.1kΩ,
TA= +25°C, unless otherwise noted.) (Note 1)
PARAMETER CONDITIONS
MIN
TYP
MAX
UNITS
Operating Frequency Range 50 878
MHz
Input Return Loss Diplex filter included, worst case across band, any gain
setting (Note 2) 5.4 8.5 dB
Input Power Range Per Channel -35
+50
dBmV
Voltage Gain Maximum gain 9.7
12.4 15.7
dB
Linear Gain-Control Range Measured at 50MHz, difference between maximum and
minimum gain 19 23 dB
Gain Flatness From 50MHz to 878MHz, VRFAGC = 3V (Note 2) 2.9 dB
Noise Figure Maximum gain, diplexer loss included 5 dB
Maximum gain, VRFAGC = 3V (Notes 2, 3) 27 34
Input 2nd-Order Intercept Point Minimum gain, VRFAGC = 1V
47.6
53
dBm
Maximum gain, VRFAGC = 3V (Note 4)
15.4
19
Input 3rd-Order Intercept Point Minimum gain, VRFAGC = 1V (Note 2) 30 33
dBm
1dB Compression Point Maximum gain. (Note 2) 2.2 4
dBm
Shutdown mode, 50MHz to 878MHz, RF input to RF
output 41
Isolation
Port to port 24
dBc
Output Return Loss Unbalanced 75Ω load 10 dB
Note 1: Guaranteed by production test at TA= +25°C and +85°C and does not include diplex filter loss, unless otherwise noted.
Note 2: Guaranteed by design and characterization from TA= 0°C to +85°C.
Note 3: Tested with input tones at 210MHz and 660MHz at -12dBm/tone. Diplexer is not included.
Note 4: Tested with input tones at 760MHz and 810MHz at -12dBm/tone. Diplexer is not included.
MAX3537/MAX3538
Broadband Variable-Gain Amplifiers
4_______________________________________________________________________________________
Typical Operating Characteristics
(MAX3537 EV kit with diplex filter removed, VCC = 5V, VRFAGC = 3V, TA= +25°C, unless otherwise noted.)
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX3537 toc01
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
5.25.14.8 4.9 5.0
32
34
36
38
40
42
44
46
30
4.7 5.3
TA = 0°C
TA = +25°C
TA = +85°C
0
4
2
8
6
12
10
14
18
16
20
10 230 340 450120 560
GAIN vs. FREQUENCY
MAX3537 toc02
FREQUENCY (MHz)
GAIN (dB)
TA = +85°C
670 780 890 1000
TA = +25°C
TA = 0°C
GAIN vs. GAIN-CONTROL VOLTAGE
MAX3537 toc03
VRFAGC (V)
GAIN (dB)
2.82.62.42.22.01.81.61.41.2
-10
-5
0
5
10
15
-15
1.0 3.0
fRF = 878MHz
fRF = 50MHz
2
4
3
6
5
8
7
9
11
10
12
10 230 340 450120 560
NOISE FIGURE vs. FREQUENCY
MAX3537 toc04
FREQUENCY (MHz)
NOISE FIGURE (dB)
TA = +85°C
670 780 890 1000
TA = +25°C
TA = 0°C
0
10
5
20
15
30
25
35
-15 -5-10 0 5 10
NOISE FIGURE vs. GAIN
MAX3537 toc05
GAIN (dB)
NOISE FIGURE (dB)
fRF = 50MHz
fRF = 878MHz
IIP2 vs. GAIN-CONTROL VOLTAGE
MAX3537 toc06
VRFAGC (V)
IIP2 (dBm)
2.82.62.2 2.41.4 1.6 1.8 2.01.2
25
30
35
40
45
50
55
60
65
70
20
1.0 3.0
f1 = 400MHz
f2 = 450MHz
10
20
15
25
40
45
35
30
50
1.0 1.4 1.6 1.8 2.01.2 2.2 2.4 2.6 2.8 3.0
IIP3 vs. VRFAGC
MAX3537 toc07
VRFAGC (V)
IIP3 (dBm)
f1 = 400MHz
f2 = 450MHz
30.00
20.00
25.00
10.00
15.00
5.00
0
50 410 530170 290 650 770 890
INPUT RETURN LOSS vs. FREQUENCY
MAX3537 toc08
FREQUENCY (MHz)
INPUT RETURN LOSS (dB)
A: TA = +85°C, UHF_IN ENABLED
B: TA = +25°C, UHF_IN ENABLED
C: TA = 0°C, UHF_IN ENABLED
D: TA = +85°C, VHF_IN ENABLED
E: TA = +25°C, VHF_IN ENABLED
F: TA = 0°C, VHF_IN ENABLED
F
E
D
A
B
C
WITH DIPLEXER
20.00
12.00
14.00
4.00
6.00
2.00
0
50 410 530170 290 650 770 890
OUTPUT RETURN LOSS vs. FREQUENCY
MAX3537 toc09
FREQUENCY (MHz)
OUTPUT RETURN LOSS (dB)
A: TA = +85°C, UHF_IN ENABLED
B: TA = +25°C, UHF_IN ENABLED
C: TA = 0°C, UHF_IN ENABLED
D: TA = +85°C, VHF_IN ENABLED
E: TA = +25°C, VHF_IN ENABLED
F: TA = 0°C, VHF_IN ENABLED
WITH DIPLEXER
8.00
10.00
16.00
18.00
C
AB
D
E
F
MAX3537
MAX3537/MAX3538
Broadband Variable-Gain Amplifiers
_______________________________________________________________________________________ 5
Typical Operating Characteristics (continued)
(MAX3537 EV kit with diplex filter removed, VCC = 5V, VRFAGC = 3V, TA= +25°C, unless otherwise noted.)
MAX3537
GAIN vs. RBIAS
MAX3537 toc11
RBIAS (kΩ)
GAIN (dB)
14.213.412.6
2
4
6
8
10
12
14
16
0
11.8 15.0
fRF = 400MHz
-70.00
-60.00
-65.00
-50.00
-55.00
-40.00
-45.00
-35.00
-25.00
-30.00
-20.00
10 230 340 450120 560
SHUTDOWN ISOLATION
vs. FREQUENCY
MAX3537 toc12
FREQUENCY (MHz)
GAIN (dB)
670 780 890 1000
WITH DIPLEXER
25
31
29
27
33
35
37
39
41
43
45
11.8 12.6 13.4 14.2 15.0
SUPPLY CURRENT AND IIP3 vs. RBIAS
MAX3537 toc10
RBIAS (kΩ)
SUPPLY CURRENT (mA)
CURRENT
IIP3
IIP3 (dBm)
7
9
19
21
23
25
5
11
13
15
17
f1 = 400MHz
f2 = 450MHz
PIN = -12dBm/tone
Typical Operating Characteristics
(MAX3538 EV kit with diplex filter removed, VCC = 5V, VRFAGC = 3V, TA= +25°C, unless otherwise noted.)
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX3538 toc01
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
5.25.14.8 4.9 5.0
42
44
46
48
50
52
54
56
40
4.7 5.3
TA = 0°C
TA = +25°C
TA = +85°C
6
8
7
10
9
12
11
13
15
14
16
10 230 340 450120 560
GAIN vs. FREQUENCY
MAX3538 toc02
FREQUENCY (MHz)
GAIN (dB)
670 780 890 1000
TA = +85°C
TA = +25°CTA = 0°C
GAIN vs. GAIN-CONTROL VOLTAGE
MAX3538 toc03
VRFAGC (V)
GAIN (dB)
2.82.62.42.22.01.81.61.41.2
-10
-5
0
5
10
15
-15
1.0 3.0
fRF = 878MHz
fRF = 50MHz
MAX3538
MAX3537/MAX3538
Broadband Variable-Gain Amplifiers
6_______________________________________________________________________________________
Typical Operating Characteristics (continued)
(MAX3538 EV kit with diplex filter removed, VCC = 5V, VRFAGC = 3V, TA= +25°C, unless otherwise noted.)
2
4
3
6
5
8
7
9
11
10
12
10 230 340 450120 560
NOISE FIGURE vs. FREQUENCY
MAX3538 toc04
FREQUENCY (MHz)
NOISE FIGURE (dB)
670 780 890 1000
TA = 0°C
TA = +85°C
TA = +25°C
0
10
5
15
25
20
30
-15 -5-10 0 5 15
NOISE FIGURE vs. GAIN
MAX3538 toc05
GAIN (dB)
NOISE FIGURE (dB)
10
fRF = 50MHz
fRF = 878MHz
30
40
35
45
60
65
55
50
70
1.0 1.4 1.6 1.8 2.01.2 2.2 2.4 2.6 2.8 3.0
IIP2 vs. VRFAGC
MAX3538 toc06
VRFAGC (V)
IIP2 (dBm)
f1 = 400MHz
f2 = 450MHz
10
20
15
25
40
45
35
30
50
1.0 1.4 1.6 1.8 2.01.2 2.2 2.4 2.6 2.8 3.0
IIP3 vs. VRFAGC
MAX3538 toc07
VRFAGC (V)
IIP2 (dBm)
f1 = 400MHz
f2 = 450MHz
30.00
20.00
25.00
10.00
15.00
5.00
0
50 410 530170 290 650 770 890
INPUT RETURN LOSS vs. FREQUENCY
MAX3538 toc08
FREQUENCY (MHz)
INPUT RETURN LOSS (dB)
A: TA = +85°C, UHF_IN ENABLED
B: TA = +25°C, UHF_IN ENABLED
C: TA = 0°C, UHF_IN ENABLED
D: TA = +85°C, VHF_IN ENABLED
E: TA = +25°C, VHF_IN ENABLED
F: TA = 0°C, VHF_IN ENABLED
A, B, C
WITH DIPLEXER
F
D
E
30.00
20.00
25.00
10.00
15.00
5.00
0
50 410 530170 290 650 770 890
OUTPUT RETURN LOSS vs. FREQUENCY
MAX3538 toc09
FREQUENCY (MHz)
OUTPUT RETURN LOSS (dB)
A: TA = +85°C, UHF_IN ENABLED
B: TA = +25°C, UHF_IN ENABLED
C: TA = 0°C, UHF_IN ENABLED
D: TA = +85°C, VHF_IN ENABLED
E: TA = +25°C, VHF_IN ENABLED
F: TA = 0°C, VHF_IN ENABLED
WITH DIPLEXER
F
D
E
A, B, C
30
36
34
32
38
40
42
44
46
48
50
9.1 10.0 10.9 11.8
SUPPLY CURRENT AND IIP3 vs. RBIAS
MAX3538 toc10
RBIAS (kΩ)
SUPPLY CURRENT (mA)
CURRENT
IIP3 (dBm)
7
9
19
21
23
25
5
11
13
15
17
IIP3
f1 = 400MHz
f2 = 450MHz
PIN = -12dBm/tone
GAIN vs. RBIAS
MAX3538 toc11
RBIAS (kΩ)
GAIN (dB)
10.910.0
4
6
8
10
12
14
16
18
2
9.1 11.8
fRF = 400MHz
-70.00
-60.00
-65.00
-50.00
-55.00
-40.00
-45.00
-35.00
-25.00
-30.00
-20.00
10 230 340 450120 560
SHUTDOWN ISOLATION
vs. FREQUENCY
MAX3538 toc12
FREQUENCY (MHz)
GAIN (dB)
670 780 890
WITH DIPLEXER
MAX3538
Detailed Description
The MAX3537/MAX3538 variable-gain amplifiers are
designed for US digital television applications, specifi-
cally to meet ATSC’s recommended receiver require-
ments. The MAX3538 uses an external pullup inductor
for maximum linearity and gain and is ideal for perfor-
mance-driven applications. The MAX3537 does not
require an external pullup inductor and requires 10mA
less current than the MAX3538. This results in slightly
lower linearity and gain but is an acceptable option for
cost- and/or power-sensitive applications. The two
parts are otherwise identical and can use the same lay-
out and application schematic except for the pullup
inductor and RBIAS resistor.
Dual-Band Inputs
The MAX3537/MAX3538 feature two RF inputs, one for
the VHF band (50MHz to 230MHz) and one for the UHF
band (470MHz to 810MHz). An external diplex filter
attenuates the undesired band. The diplex filter is easily
implemented with discrete components, see the Typical
Application Circuit for typical component values.
Selection between the two inputs is achieved with a sin-
gle digital input, SEL_UHF. See Table 1 for a description
of SEL_UHF operation. The VHF and UHF inputs are ter-
minated into approximately 75Ωwhen not selected.
Broadband Variable-Gain Amplifier (VGA)
The MAX3537/MAX3538 integrate a broadband low-
noise variable-gain amplifier. The MAX3538 VGA has
an open-collector output and requires a pullup inductor
to VCC, while the MAX3537 has an internal pullup to
VCC. Both the MAX3537 and MAX3538 outputs require
a DC-blocking capacitor.
The MAX3537/MAX3538 provide a 22dB gain-control
range for increased system linearity. A DC voltage
applied at the RFAGC pin controls the devices’ overall
gain, and can range from 1V to 3V with 3V providing
the maximum gain setting.
MAX3537/MAX3538
Broadband Variable-Gain Amplifiers
_______________________________________________________________________________________ 7
PIN
NAME FUNCTION
1UHF_IN UHF Input. This input is terminated into 75Ω when not selected.
2RF_GND1 First RF Ground. Connect a 1000pF capacitor from RF_GND1 to GND. Do not connect RF_GND1 to
RF_GND2.
3
UHF_SHUNT
UHF Shunt. Connects to GND when SEL_UHF is low, high impedance when SEL_UHF is high.
4RBIAS Amplifier Bias. Connect an 11.8kΩ ±1% (MAX3537) or 9.1kΩ ±1% (MAX3538) resistor from RBIAS to GND.
5SEL_UHF
Band - S el ect Inp ut. S el ects b etw een the U H F and V H F i np uts. Log i c l ow to sel ect V H F, l og i c hi g h to sel ect U H F.
6SHDN Shutdown. Logic low to put the device in standby mode. Logic high for normal operation.
7RFAGC Automatic Gain-Control Input. Accepts a DC voltage from 1V (minimum gain) to 3V (maximum gain).
8V
C C S up p l y V ol tag e. Byp ass to G N D w i th 47p F and 1000p F cap aci tor s p l aced as cl ose to the d evi ce as p ossi b l e.
9LNAOUT RF Output. Requires a DC-blocking capacitor. The MAX3538 requires a 560nH pullup inductor from
LNAOUT to VCC.
10
GND Ground
11
RF_GND2 Second RF Ground. Connect a 1000pF capacitor from RF_GND2 to GND. Do not connect RF_GND2 to
RF_GND1.
12
VHF_IN VHF Input. This input is terminated into approximately 75Ω when not selected.
EP
GND Exposed Paddle. Solder evenly to the board’s ground plane for proper operation.
Pin Description
Table 1. SEL_UHF Operation
SEL_UHF
FUNCTION
0Receive VHF channels (50MHz to 230MHz) or
cable channels below approximately 305MHz.
1Receive UHF channels (470MHz to 810MHz) or
cable channels above approximately 305MHz.
MAX3537/MAX3538
Applications Information
Terrestrial Television Applications
Television receivers having dedicated RF inputs for cable
and terrestrials reception can optimize the terrestrial path
to better meet the difficult requirements recommended by
ATSC. For dedicated terrestrial reception, the diplex filter
is optimized for reception of VHF and UHF channels
(50MHz to 230MHz, and 470MHz to 810MHz). The diplex
filter attenuates the undesired channels, improving sec-
ond-order distortion performance.
Terrestrial + Cable Television Applications
Television receivers having one RF input or multiple
inputs that must receive cable and terrestrial channels
must cover a 50MHz to 860MHz frequency range. The
diplex filter must allow reception within this range while
still providing attenuation of the undesired band. The
Typical Application Circuit provides acceptable gain and
noise figure performance over the diplexer transition
band between VHF and UHF, see Figures 1 and 3.
Layout Considerations
The EV kit serves as a guide for PC board layout. Keep
RF signal lines as short as possible to minimize losses
and radiation. Use controlled impedance on all high-
frequency traces. For proper operation, solder the
exposed paddle evenly to the ground plane. Use abun-
dant vias beneath the exposed paddle for maximum
heat dissipation. Use abundant ground vias between
RF traces to minimize undesired coupling. Bypass VCC
to ground with 47nF and 1000nF capacitors placed as
close to the pin as possible, with the 47nF capacitor
closest to the device.
Chip Information
TRANSISTOR COUNT: 1982
PROCESS: BiCMOS
Broadband Variable-Gain Amplifiers
8_______________________________________________________________________________________
-20.00
-10.00
-15.00
5.00
0
-5.00
15.00
10.00
20.00
10 340 450120 230 560 670 780 890 1000
TYPICAL APPLICATION CIRCUIT
FREQUENCY RESPONSE
FREQUENCY (MHz)
GAIN (dB)
A
B
C
D
A: MAX3538, VHF_IN ENABLED
B: MAX3537, VHF_IN ENABLED
C: MAX3538, UHF_IN ENABLED
D: MAX3537, UHF_IN ENABLED
Figure 1. Frequency Response of the MAX3537/MAX3538
Typical Application Circuit
2
4
3
7
6
5
9
8
10
10 340 450120 230 560 670 780 890 1000
TYPICAL APPLICATION CIRCUIT
NOISE FIGURE (MAX3537)
FREQUENCY (MHz)
NF (dB)
VHF_IN ENABLED
UHF_IN ENABLED
Figure 2. Noise Figure of MAX3537 Typical Application Circuit
2
4
3
7
6
5
9
8
10
10 340 450120 230 560 670 780 890 1000
TYPICAL APPLICATION CIRCUIT
NOISE FIGURE (MAX3538)
FREQUENCY (MHz)
NF (dB)
VHF_IN ENABLED
UHF_IN ENABLED
Figure 3. Noise Figure of MAX3538 Typical Application Circuit
MAX3537/MAX3538
Broadband Variable-Gain Amplifiers
_______________________________________________________________________________________ 9
12 11 10
456
1
2
RF_GND1
3
9
8
7
R1*
R2
20kΩ
UHF_SHUNT
*
R1
L2
MAX3537
11.8kΩ
OPEN
MAX3538
9.1kΩ
560nH
LNAOUT
INPUT
VCC
RFAGC
ENABLE
SEL_UHF
UHF_IN
RFIN
C1
6.8pF
C2
6.8pF
C3
1000pF
C5
47pF
C6
1000pF
L2
8.2nH
L2*
VCC
VRFAGC
L1
22nH
RF_GND2
GND
VHF_IN
SEL_UHF
RBIAS
SHDN
MAX3537/3538
C11
1000pF L4
56nH
L3
56nH
C10
10pF
C12
4.7pF
C8
1000pF
C7
1000pF TV TUNER
C4
100nF
Figure 4. Typical Application Circuit
Typical Application Circuit
MAX3537/MAX3538
Broadband Variable-Gain Amplifiers
10 ______________________________________________________________________________________
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages.)
24L QFN THIN.EPS
C
1
2
21-0139
PACKAGE OUTLINE
12, 16, 20, 24L THIN QFN, 4x4x0.8mm
MAX3537/MAX3538
Broadband Variable-Gain Amplifiers
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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 11
©2004 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages.)
C2
2
21-0139
PACKAGE OUTLINE
12, 16, 20, 24L THIN QFN, 4x4x0.8mm
