19-3445; Rev 1; 6/05
IT
TION K
VALUA
E
BLE
AVAILA
Broadband Variable-Gain Amplifiers
General Description
Features
o
Low-Noise VGA Eliminates PIN Attenuator
o
22dB Gain-Control Range
o
Low Noise Figure: 5dB at Maximum Gain Setting
o
High Linearity: +19dBm IIP3 (MAX3538) at
Maximum Gain Setting
o
Low Power Consumption: <200mW (MAX3537)
o
Available in a 4mm x 4mm, 12-Pin Thin QFN
Package
MAX3537/MAX3538
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).
Ordering Information
PART
MAX3537UTC
MAX3537UTC+
MAX3538UTC
MAX3538UTC+
TEMP
RANGE
PIN-PACKAGE
PKG
CODE
T1244-3
T1244-3
T1244-3
T1244-3
Applications
OpenCable Set-Top Boxes and Televisions
Digital Set-Top Boxes
Media Gateways
Digital Terrestrial Receivers
TV IF Strips
0°C to +85°C 12 Thin QFN-EP*
0°C to +85°C 12 Thin QFN-EP*
0°C to +85°C 12 Thin QFN-EP*
0°C to +85°C 12 Thin QFN-EP*
*EP
= Exposed paddle.
+Denotes
lead-free package.
Pin Configuration/
Functional Diagram
OpenCable is a trademark of Cable Television Laboratories, Inc.
RF_GND2
11
VHF_IN
GND
10
12
UHF_IN
RF_GND1
UHF_SHUNT
1
2
3
9
8
7
LNAOUT
V
CC
RFAGC
MAX3537/3538
4
RBIAS
5
SEL_UHF
6
SHDN
________________________________________________________________
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.
Broadband Variable-Gain Amplifiers
MAX3537/MAX3538
ABSOLUTE MAXIMUM RATINGS
V
CC
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 (V
CC
+ 0.3V)
LNAOUT Short-Circuit Duration..............................................10s
UHFIN, VHFIN Maximum RF Input Power.........................14dBm
Continuous Power Dissipation (T
A
= +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
CAUTION!
ESD SENSITIVE DEVICE
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
(MAX3537/MAX3538 EV kit, V
CC
= 4.75V to 5.25V, no RF signal applied, T
A
= 0°C to +85°C, unless otherwise noted. Typical values
are at V
CC
= 5V, R
BIAS
= 11.8kΩ (MAX3537) or 9.1kΩ (MAX3538), T
A
= +25°C, unless otherwise noted.) (Note 1)
PARAMETER
Supply Voltage
Supply Current
RFAGC Input Bias Current
RFAGC Control Voltage (Note 2)
Input Logic-Level Low
Input Logic-Level High
0.7 x
V
CC
Operational mode
MAX3537
MAX3538
-50
3
1
0.3 x
V
CC
CONDITIONS
MIN
4.75
38
48
2
TYP
MAX
5.25
45.8
58
100
+50
UNITS
V
mA
µA
µA
V
V
V
Standby mode (V
ENABLE
= V
SEL_UHF
= 0.1V)
V
RFAGC
= 1V and 3V
Maximum gain
Minimum gain
AC ELECTRICAL CHARACTERISTICS (MAX3537)
(MAX3537 EV kit, V
CC
= 4.75V to 5.25V, T
A
= 0°C to +85°C, unless otherwise noted. Typical values are at V
CC
= 5V, R
BIAS
= 11.8kΩ,
T
A
= +25°C, unless otherwise noted.) (Note 1)
PARAMETER
Operating Frequency Range
Input Return Loss
Input Power Range Per Channel
Voltage Gain
Linear Gain-Control Range
Gain Flatness
Noise Figure
Input 2nd-Order Intercept Point
Maximum gain
Measured at 50MHz, difference between maximum and
minimum gain
From 50MHz to 878MHz, V
RFAGC
= 3V (Note 2)
Maximum gain, diplexer loss included
Maximum gain, V
RFAGC
= 3V (Notes 2, 3)
Minimum gain, V
RFAGC
= 1V
21.6
42.5
5
26
48
Diplex filter included, worst case across band, any gain
setting (Note 2)
CONDITIONS
MIN
50
4.3
-35
7.7
19.2
9.6
23.1
2.8
8.5
+50
12.7
TYP
MAX
878
UNITS
MHz
dB
dBmV
dB
dB
dB
dB
dBm
2
_______________________________________________________________________________________
Broadband Variable-Gain Amplifiers
AC ELECTRICAL CHARACTERISTICS (MAX3537) (continued)
(MAX3537 EV kit, V
CC
= 4.75V to 5.25V, T
A
= 0°C to +85°C, unless otherwise noted. Typical values are at V
CC
= 5V, R
BIAS
= 11.8kΩ,
T
A
= +25°C, unless otherwise noted.) (Note 1)
PARAMETER
Input 3rd-Order Intercept Point
1dB Compression Point
Isolation
Output Return Loss
CONDITIONS
Maximum gain, V
RFAGC
= 3V (Note 4)
Minimum gain, V
RFAGC
= 1V (Note 2)
Maximum gain (Note 2)
Shutdown mode, 50MHz to 878MHz, RF input to RF
output
Port to port
Unbalanced 75Ω load
MIN
12.7
28.2
0
TYP
17
33
1.9
37
23
10
dB
MAX
UNITS
dBm
dBm
dBc
MAX3537/MAX3538
AC ELECTRICAL CHARACTERISTICS (MAX3538)
(MAX3538 EV kit, V
CC
= 4.75V to 5.25V, T
A
= 0°C to +85°C, unless otherwise noted. Typical values are at V
CC
= 5V, R
BIAS
= 9.1kΩ,
T
A
= +25°C, unless otherwise noted.) (Note 1)
PARAMETER
Operating Frequency Range
Input Return Loss
Input Power Range Per Channel
Voltage Gain
Linear Gain-Control Range
Gain Flatness
Noise Figure
Input 2nd-Order Intercept Point
Input 3rd-Order Intercept Point
1dB Compression Point
Isolation
Output Return Loss
Maximum gain
Measured at 50MHz, difference between maximum and
minimum gain
From 50MHz to 878MHz, V
RFAGC
= 3V (Note 2)
Maximum gain, diplexer loss included
Maximum gain, V
RFAGC
= 3V (Notes 2, 3)
Minimum gain, V
RFAGC
= 1V
Maximum gain, V
RFAGC
= 3V (Note 4)
Minimum gain, V
RFAGC
= 1V (Note 2)
Maximum gain. (Note 2)
Shutdown mode, 50MHz to 878MHz, RF input to RF
output
Port to port
Unbalanced 75Ω load
27
47.6
15.4
30
2.2
5
34
53
19
33
4
41
24
10
dB
Diplex filter included, worst case across band, any gain
setting (Note 2)
CONDITIONS
MIN
50
5.4
-35
9.7
19
12.4
23
2.9
8.5
+50
15.7
TYP
MAX
878
UNITS
MHz
dB
dBmV
dB
dB
dB
dB
dBm
dBm
dBm
dBc
Note 1:
Note 2:
Note 3:
Note 4:
Guaranteed by production test at T
A
= +25°C and +85°C and does not include diplex filter loss, unless otherwise noted.
Guaranteed by design and characterization from T
A
= 0°C to +85°C.
Tested with input tones at 210MHz and 660MHz at -12dBm/tone. Diplexer is not included.
Tested with input tones at 760MHz and 810MHz at -12dBm/tone. Diplexer is not included.
_______________________________________________________________________________________
3
Broadband Variable-Gain Amplifiers
MAX3537/MAX3538
Typical Operating Characteristics
(MAX3537 EV kit with diplex filter removed, V
CC
= 5V, V
RFAGC
= 3V, T
A
= +25°C, unless otherwise noted.)
MAX3537
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX3537 toc01
GAIN vs. FREQUENCY
MAX3537 toc02
GAIN vs. GAIN-CONTROL VOLTAGE
MAX3537 toc03
46
44
SUPPLY CURRENT (mA)
42
40
38
36
34
32
30
4.7
4.8
4.9
5.0
5.1
5.2
T
A
= 0°C
T
A
= +25°C
20
18
16
14
GAIN (dB)
12
10
8
6
4
2
0
T
A
= +85°C
T
A
= +25°C
T
A
= 0°C
15
10
f
RF
= 878MHz
5
GAIN (dB)
0
-5
-10
-15
T
A
= +85°C
f
RF
= 50MHz
5.3
SUPPLY VOLTAGE (V)
10 120 230 340 450 560 670 780 890 1000
FREQUENCY (MHz)
1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0
V
RFAGC
(V)
NOISE FIGURE vs. FREQUENCY
MAX3537 toc04
NOISE FIGURE vs. GAIN
MAX3537 toc05
IIP2 vs. GAIN-CONTROL VOLTAGE
65
60
55
IIP2 (dBm)
50
45
40
35
30
f
1
= 400MHz
f
2
= 450MHz
1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0
V
RFAGC
(V)
MAX3537 toc06
12
11
10
NOISE FIGURE (dB)
9
8
7
6
5
4
3
2
T
A
= 0°C
T
A
= +85°C
T
A
= +25°C
35
30
NOISE FIGURE (dB)
25
20
15
10
5
0
f
RF
= 50MHz
70
f
RF
= 878MHz
-15
-10
-5
0
5
10
25
20
10 120 230 340 450 560 670 780 890 1000
FREQUENCY (MHz)
GAIN (dB)
IIP3 vs. V
RFAGC
MAX3537 toc07
INPUT RETURN LOSS vs. FREQUENCY
WITH DIPLEXER
5.00
INPUT RETURN LOSS (dB)
B
10.00
15.00
20.00
25.00
30.00
50
170
290
410
530
650
770
890
FREQUENCY (MHz)
A: T
A
= +85°C, UHF_IN ENABLED D: T
A
= +85°C, VHF_IN ENABLED
B: T
A
= +25°C, UHF_IN ENABLED E: T
A
= +25°C, VHF_IN ENABLED
C: T
A
= 0°C, UHF_IN ENABLED F: T
A
= 0°C, VHF_IN ENABLED
D
E
F
C
A
MAX3537 toc08
OUTPUT RETURN LOSS vs. FREQUENCY
2.00
OUTPUT RETURN LOSS (dB)
4.00
6.00
8.00
10.00
12.00
14.00
16.00
18.00
20.00
50
170
290
410
530
650
770
890
FREQUENCY (MHz)
A: T
A
= +85°C, UHF_IN ENABLED D: T
A
= +85°C, VHF_IN ENABLED
B: T
A
= +25°C, UHF_IN ENABLED E: T
A
= +25°C, VHF_IN ENABLED
C: T
A
= 0°C, UHF_IN ENABLED F: T
A
= 0°C, VHF_IN ENABLED
F
E
D
WITH DIPLEXER
A
B
C
MAX3537 toc09
50
45
40
IIP3 (dBm)
35
30
25
20
15
10
f
1
= 400MHz
f
2
= 450MHz
0
0
1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0
V
RFAGC
(V)
4
_______________________________________________________________________________________
Broadband Variable-Gain Amplifiers
Typical Operating Characteristics (continued)
(MAX3537 EV kit with diplex filter removed, V
CC
= 5V, V
RFAGC
= 3V, T
A
= +25°C, unless otherwise noted.)
MAX3537/MAX3538
MAX3537
SUPPLY CURRENT AND IIP3 vs. R
BIAS
MAX3537 toc10
GAIN vs. R
BIAS
MAX3537 toc11
43
41
SUPPLY CURRENT (mA)
39
37
35
33
31
29
27
25
11.8
12.6
13.4
R
BIAS
(kΩ)
14.2
f
1
= 400MHz
f
2
= 450MHz
P
IN
= -12dBm/tone
CURRENT
IIP3
23
21
19
GAIN (dB)
17
15
13
11
9
7
5
IIP3 (dBm)
14
12
f
RF
= 400MHz
-25.00
-30.00
-35.00
WITH DIPLEXER
8
6
4
2
0
11.8
12.6
13.4
R
BIAS
(kΩ)
14.2
15.0
GAIN (dB)
10
-40.00
-45.00
-50.00
-55.00
-60.00
-65.00
-70.00
10 120 230 340 450 560 670 780 890 1000
FREQUENCY (MHz)
15.0
Typical Operating Characteristics
(MAX3538 EV kit with diplex filter removed, V
CC
= 5V, V
RFAGC
= 3V, T
A
= +25°C, unless otherwise noted.)
MAX3538
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX3538 toc01
GAIN vs. FREQUENCY
15
14
13
GAIN (dB)
GAIN (dB)
12
11
10
9
T
A
= +85°C
T
A
= +25°C
MAX3538 toc02
GAIN vs. GAIN-CONTROL VOLTAGE
MAX3538 toc03
56
54
SUPPLY CURRENT (mA)
52
50
48
46
44
42
40
4.7
4.8
4.9
5.0
5.1
5.2
T
A
= 0°C
T
A
= +25°C
T
A
= +85°C
16
15
10
f
RF
= 878MHz
5
0
-5
-10
-15
f
RF
= 50MHz
T
A
= 0°C
8
7
6
5.3
SUPPLY VOLTAGE (V)
10 120 230 340 450 560 670 780 890 1000
FREQUENCY (MHz)
1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0
V
RFAGC
(V)
_______________________________________________________________________________________
5
MAX3537 toc12
45
SHUTDOWN ISOLATION
vs. FREQUENCY
-20.00
25
16
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
