19-2301; Rev 1; 10/06
KIT
ATION
EVALU
BLE
AVAILA
LNAs with Step Attenuator and VGA
Features
♦
Low Noise Figure (1.8dB typical)
♦
High Small-Signal Gain (15dB Nominal)
♦
Wide Frequency Range of Operation
(100MHz to 1GHz)
♦
20dB Step Attenuator
♦
45dB AGC Range Excluding Step Attenuator
♦
2.65V to 3.3V Single-Supply Operation
♦
Shutdown Mode
♦
3.5mA Supply Current, Adjustable Down to 2.5mA
♦
40dB Reverse Isolation
General Description
The MAX2371/MAX2373 wideband low-noise amplifier
(LNA) ICs are designed for direct conversion receiver
(DCR) or very low intermediate frequency (VLIF) receiver
applications. They contain single-channel, single-ended
LNAs with switchable attenuator and automatic gain con-
trol (AGC) intended as a low-noise gain stage. These
devices provide high gain-control range (typically 60dB)
at radio frequency (RF) with excellent noise and reverse
isolation characteristics.
The MAX2371/MAX2373 can work over the frequency
range from 100MHz to 1GHz. In practice, only a narrow
band is needed in each application, so different matching
circuits can be applied. The devices are dynamically con-
figured through the digital/analog control pins to select
either maximum gain and low noise figure or power-saving
mode. In addition, the MAX2371/MAX2373 feature
high/low-current modes, high/low attenuation modes, lin-
early controlled gain states, and shutdown mode.
MAX2371/MAX2373
Ordering Information
PART
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-
PACKAGE
12 QFN-EP*
12 TQFN-EP*
12 TQFN-EP*
12 QFN-EP*
12 TQFN-EP*
12 TQFN-EP*
PKG
CODE
G1233-1
T1233-3
T1233+3
G1233-1
T1233-3
T1233+3
Applications
Direct Conversion Receiver (DCR)
Very Low IF Receiver
MAX2371EGC
MAX2371ETC
MAX2373EGC
MAX2373ETC
MAX2371ETC+ -40°C to +85°C
MAX2373ETC+ -40°C to +85°C
*EP
= Exposed pad.
+Denotes
lead-free package.
Pin Configuration
TOP VIEW
GND
12
RF_V
CC
RSET
11
10
LNA_IN
GND
Functional Diagram
RF_V
CC
RSET
AGC_BYP
MAX2371
MAX2373
LNA_V
CC
LNA_IN
LNA_E
RX_EN
1
2
3
9
8
7
AGC_BYP
LNA_V
CC
LNA_OUT
LNA_E
RF
ATTENUATOR
LNA
AGC
AMP
LNA_OUT
MAX2371
MAX2373
RX_EN
EXPONENTIAL
CONVERTER
4
5
6
LNA_I
RF_ATTN
AGC
LNA_I
RF_ATTN AGC
QFN/TQFN
________________________________________________________________
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.
LNAs with Step Attenuator and VGA
MAX2371/MAX2373
ABSOLUTE MAXIMUM RATINGS
V
CC
to GND ...........................................................-0.3V to +3.6V
All Pins Excluding Grounds to Pin GND.....-0.3V to (V
CC
+ 0.3V)
LNA Input Power (RX_EN = low) ........................................5dBm
Continuous Power Dissipation (T
A
= +70°C)
12-Pin QFN (derate 11.9mW/°C above +70°C) ...........952mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +160°C
Soldering Temperature (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
(V
CC
= 2.775V, RX_EN = high, R
SET
= 1.1kΩ, V
AGC
= V
CC
/2, T
A
= -40°C to +85°C. Typical values are at T
A
= +25°C, unless other-
wise noted.)
PARAMETER
Supply Voltage
Supply Current
Digital Input Logic High
Digital Input Logic Low
Logic Pin Impedance
AGC Pin Impedance
SYMBOL
V
CC
RX_EN = low, V
CC
= 3.3V
I
CC
V
IH
V
IL
LNA_I = high, RF_ATTN = low
LNA_I = low
Pins LNA_I, RF_ATTN, RX_EN
Pins LNA_I, RF_ATTN, RX_EN
Logic pins RX_EN, RF_ATTN, LNA_I
Pins AGC
0.7
✕
V
CC
0
50
100
CONDITIONS
MIN
2.65
TYP
2.775
0.5
3.5
2.5
MAX
3.30
20
5.5
3.5
V
CC
0.3
✕
V
CC
UNITS
V
µA
mA
mA
V
V
kΩ
kΩ
AC ELECTRICAL CHARACTERISTICS
(MAX2371/MAX2373 EV Kits, V
CC
= 2.65V to 3.3V, RX_EN = high, R
SET
= 1.1kΩ, T
A
= -40°C to +85°C. Typical values are at V
CC
=
2.775V; for MAX2371 f
RF
= 150MHz, for MAX2373 f
RF
= 850MHz to 940MHz; T
A
= +25°C, unless otherwise noted.) (Note 1)
PARAMETER
LNA AND AGC AMP CHARACTERISTICS
Radio Frequency Range (Note 2)
Low band (MAX2371)
High band (MAX2373)
LNA_I = high;
RF_ATTN = low
LNA_I = high;
RF_ATTN = high
Over AGC range
LNA_I = high, T
A
=
+25°C, V
CC
= 2.775V
LNA_I = low, T
A
=
+25°C, V
CC
= 2.775V
Gain Variation Over Temperature
MAX2371
MAX2373
MAX2371
MAX2373
MAX2371
MAX2373
MAX2371
MAX2373
MAX2371
MAX2373
13
14
10.5
10.5
-2.0
136
850
150
900
-12
-15
-14
-10
-40
-42
14.5
15.5
12
13
2.0
dB
174
940
-9.5
-9.5
-10
-6.5
-35
-35
16
17
dB
dB
dB
MHz
CONDITIONS
MIN
TYP
MAX
UNITS
Input Return Loss (S11)
(Note 3)
Reverse Isolation (S12)
Max Power Gain (Note 3)
T
A
= -40°C to +85°C, V
AGC
< 1.8V
2
_______________________________________________________________________________________
LNAs with Step Attenuator and VGA
AC ELECTRICAL CHARACTERISTICS (continued)
(MAX2371/MAX2373 EV Kits, V
CC
= 2.65V to 3.3V, RX_EN = high, R
SET
= 1.1kΩ, T
A
= -40°C to +85°C. Typical values are at V
CC
=
2.775V; for MAX2371 f
RF
= 150MHz, for MAX2373 f
RF
= 850MHz to 940MHz; T
A
= +25°C, unless otherwise noted.) (Note 1)
PARAMETER
CONDITIONS
V
AGC
= 1.275V
LNA_I = high, T
A
=
+25°C, V
CC
= 2.775V,
RF_ATTN = low
SSB Noise Figure vs. AGC
LNA_I = low, T
A
=
+25°C, V
CC
= 2.775V,
RF_ATTN = low
RF_ATTN = low,
V
AGC
< 1.8V
RF_ATTN = high,
V
AGC
< 1.8V
RF_ATTN = low,
V
AGC
= V
CC
/2
Input IP3 (Notes 4, 5)
RF_ATTN = high,
V
AGC
= V
CC
/2 to 2.575V
Input IP3 Over AGC Range
AGC RESPONSE
AGC Attenuation Range (Note 6)
AGC Slope Over Control Range
RF STEP ATTENUATOR
Gain Step
RF_ATTN = high to low,
LNA_I = high
MAX2371
MAX2373
16.0
18.0
17.5
19.5
19.0
21.0
dB
V
CC
= 2.775V, RF_ATTN = low, V
AGC
= 1.3375V
to 2.575V, T
A
= +25°C
RF_ATTN = low, V
AGC
= 1.625V
RF_ATTN = high, V
AGC
= 1.625V
35
32
24
45
40
33
47
41
dB
dB/V
V
AGC
= 1.575V
V
AGC
= 1.875V
V
AGC
= 2.175V
V
AGC
= 1.275V
LNA_I = high
LNA_I = low
LNA_I = high
LNA_I = low
LNA_I = high
LNA_I = low
LNA_I = high
MAX2371
MAX2373
MAX2371
MAX2373
-21.5
-24
-3
-9
-5
-7
-12
9
-10.5
-12.5
MIN
TYP
1.8
5.0
11
20
2.1
19.5
-22
0
-6.5
-1
-4
-9
13
-8
-10.5
dBm
dBm
dBm
dBm
2.6
MAX
2.2
7.7
14.5
dB
UNITS
MAX2371/MAX2373
Input 1dB Compression Point
RF_ATTN = low, LNA_I = high,
V
AGC
= V
CC
/2 to 1.80V
Note 1:
Note 2:
Note 3:
Note 4:
Note 5:
Note 6:
Parameters over temperature and supply voltage range are guaranteed by design and characterization, unless otherwise noted.
Operation outside these frequency bands is possible but has not been characterized. See
Typical Operating Characteristics.
Measured with external matching network.
f
IN1
= 150MHz, f
IN2
= 150.1MHz, P
IN
= -30dBm for both tones (MAX2371).
f
IN1
= 900MHz, f
IN2
= 900.1MHz, P
IN
= -30dBm for both tones (MAX2373).
Parameters are guaranteed by production test.
_______________________________________________________________________________________
3
LNAs with Step Attenuator and VGA
MAX2371/MAX2373
Typical Operating Characteristics
(MAX2371/MAX2373 EV Kits, V
CC
= 2.775V, RX_EN = high, R
SET
= 1.1kΩ, LNA_I = high, T
A
= +25°C. For MAX2371, f
RF
= 150MHz;
for MAX2373, f
RF
= 900MHz, unless otherwise noted.)
MAX2371
GAIN vs. FREQUENCY
MAX2371 toc01
GAIN vs. V
AGC
MAX2371 toc02
IIP3 vs. V
AGC
RF_ATTN = HIGH
20
15
IIP3 (dBm)
10
5
0
T
A
= +85°C
T
A
= +25°C
T
A
= -40°C
MAX2371 toc03
20
RF_ATTN = LOW
15
10
GAIN (dB)
5
0
-5
-10
130
140
150
160
170
RF_ATTN = HIGH
T
A
= +85°C T
A
= +25°C
T
A
= -40°C
20
RF_ATTN = LOW
10
0
GAIN (dB)
-10
-20
-30
-40
-50
-60
T
A
= +85°C
T
A
= +25°C
T
A
= -40°C
RF_ATTN = HIGH
25
-5
-10
RF_ATTN = LOW
-15
2.8
1.3
1.4
1.5
1.6
1.7
1.8
180
1.2
1.6
2.0
V
AGC
(V)
2.4
FREQUENCY (MHz)
V
AGC
(V)
P
1dB
vs. V
AGC
MAX2371 toc04
NOISE FIGURE vs. V
AGC
MAX2371 toc05
S11, S22, S12 vs. FREQUENCY
-5
-10
S11, S22, S12 (dB)
-15
-20
-25
-30
-35
RF_ATTN = LOW
RF_ATTN = HIGH
S11
S22
MAX2371 toc06
10.0
5.0
0
P
1dB
(dBm)
-5.0
-10.0
-15.0
RF_ATTN = LOW
-20.0
-25.0
1.2
1.7
V
AGC
(V)
2.2
2.7
T
A
= -40°C
T
A
= +25°C
T
A
= +85°C
RF_ATTN = HIGH
30
RF_ATTN = HIGH
25
NOSIE FIGURE (dB)
20
15
10
RF_ATTN = LOW
5
0
1.2
1.7
V
AGC
(V)
2.2
2.7
0
-40
-45
-50
130
140
150
160
170
180
FREQUENCY (MHz)
S12
S11, S22, S12 vs. V
AGC
S11
-10
S11, S22, S12 (dB)
-20
-30
-40
-50
-60
1.2
1.7
V
AGC
(V)
2.2
2.7
S12
S22
S11
RF_ATTN = LOW
RF_ATTN = HIGH
MAX2371 toc07
0
4
_______________________________________________________________________________________
LNAs with Step Attenuator and VGA
MAX2371/MAX2373
Typical Operating Characteristics (continued)
(MAX2371/MAX2373 EV Kits, V
CC
= 2.775V, RX_EN = high, R
SET
= 1.1kΩ, LNA_I = high, T
A
= +25°C. For MAX2371, f
RF
= 150MHz;
for MAX2373, f
RF
= 900MHz, unless otherwise noted.)
MAX2373
GAIN vs. FREQUENCY
MAX2371 toc08
GAIN vs. V
AGC
MAX2371 toc09
IIP3 vs. V
AGC
RF_ATTN = HIGH
15
10
IIP3 (dBm)
5
0
-5
-10
T
A
= -40°C
T
A
= +25°C
T
A
= +85°C
MAX2371 toc10
20
RF_ATTN = LOW
15
10
GAIN (dB)
20
RF_ATTN = LOW
10
0
GAIN (dB)
-10
-20
-30
T
A
= -40°C
T
A
= +25°C
T
A
= +85°C
RF_ATTN = HIGH
-50
20
5
0
-5
T
A
= -40°C
T
A
= +25°C
T
A
= +85°C
RF_ATTN = HIGH
-10
840
860
880
900
920
940
FREQUENCY (MHz)
-40
RF_ATTN = LOW
-15
2.8
1.3
1.4
1.5
1.6
1.7
1.8
1.2
1.6
2.0
V
AGC
(V)
2.4
V
AGC
(V)
P
1dB
vs. V
AGC
MAX2371 toc11
NOISE FIGURE vs. V
AGC
MAX2371 toc12
S11, S22, S12 vs. FREQUENCY
-5
-10
S11, S22, S12 (dB)
-15
-20
-25
-30
-35
-40
-45
S12
S11
RF_ATTN = LOW
RF_ATTN = HIGH
S22
S11
MAX2371 toc13
10.0
5.0
0
P
1dB
(dBm)
-5.0
-10.0
-15.0
RF_ATTN = LOW
-20.0
-25.0
1.2
1.7
V
AGC
(V)
2.2
2.7
T
A
= -40°C T
A
= +25°C
T
A
= 85°C
RF_ATTN = HIGH
30
25
NOSIE FIGURE (dB)
20
15
RF_ATTN = LOW
10
5
0
1.2
1.7
V
AGC
(V)
2.2
2.7
RF_ATTN = HIGH
0
-50
840
860
880
900
920
940
FREQUENCY (MHz)
S11, S22, S12 vs. V
AGC
-5
-10
S11, S22, S12 (dB)
-15
-20
-25
-30
-35
-40
-45
-50
1.2
1.7
V
AGC
(V)
2.2
2.7
S12
S22
S11
RF_ATTN = LOW
RF_ATTN = HIGH
S11
MAX2371 toc14
0
_______________________________________________________________________________________
5
