19-5655; Rev 0; 6/11
EVALUATION KIT AVAILABLE
MAX2670
GPS/GNSS Front-End Amplifier
General Description
The MAX2670 GPS/GNSS front-end amplifier IC is
designed for automotive and marine GPS/GNSS satellite
navigation antenna modules or for any application that
needs to compensate for cable losses from the antenna
to receiver. Two unconditionally stable low-noise amplifier
stages provide the high gain and integrated I/O matching
to minimize the need for external matching components
and eliminate the need for additional gain stages. The
device features the option to place a bandpass ceramic
or SAW filter between the two amplifier stages to provide
a narrow-band output to further improve the noise perfor-
mance of the GPS/GNSS receiver. Additionally, a 3.4dB
gain step is provided to compensate for cable loss varia-
tion between different applications.
The device is designed to operate across all GNSS fre-
quency standards with a 34.8dB typical cascaded gain
and a 25mA supply current. The two LNA stages allow
the use of a wide range of GNSS filter types for maxi-
mum flexibility in system design. The final RF output pin,
which drives the cable to the GNSS receiver, is also the
power-supply connection that accepts a DC supply in
the 3.0V to 5.5V range. Alternatively, the DC supply can
be applied to pin 4.
This GPS/GNSS front-end amplifier is designed on a low-
noise, advanced SiGe process and is available in a lead-
free, 10-pin TDFN surface-mount package (3mm x 3mm).
S
First Amplifier Noise Figure*: 1.0dB
S
High Gain**: 34.8dB
S
3.4dB Gain Step
S
Shared V
CC
and RFOUT2 Pin
S
Integrated 50I Output Matching
S
3.0V to 5.5V Supply Voltage Range
S
Small, Low-Cost Package (3mm x 3mm)
S
AEC-Q100 Qualified
S
ESD Protected to ±2kV Human Body Model
Features
Applications
Integrated Automotive and Marine GPS Receivers
Active Antennas
*Without
external input impedance match.
**First
amplifier input is impedance matched (S
11
= -10dB).
Second amplifier set to high gain. Amplifiers cascaded without
interstage filter.
Ordering Information
appears at end of data sheet.
Typical Operating Circuit appears at end of data sheet.
Functional Diagram
TOP VIEW
+
RFIN2
GND
GND
EXTCAP/ALT_VCC
RFOUT2/VCC
1
2
3
4
5
DC
GENERATION
AMP 2
AMP 1
MAX2670
10 RFOUT1
9
8
7
6
GND
GND
GAIN_SELECT
RFIN1
TDFN
For related parts and recommended products to use with this part, refer to
www.maxim-ic.com/MAX2670.related.
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Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
MAX2670
GPS/GNSS Front-End Amplifier
ABSOLUTE MAXIMUM RATINGS
RFOUT1, RFOUT2, EXTCAP to GND ....... -0.3V to (V
CC
+ 0.5V)
RFIN1 Input Power (50I source) .................................. +15dBm
GAIN_SELECT to GND............................. -0.3V to (V
CC
+ 0.3V)
Continuous Power Dissipation (T
A
= +70NC)
TDFN (derate 18.5mW/NC above +70NC) ..................1481mW
Operating Ambient Temperature Range ......... -40NC to +105NC
Maximum Junction Temperature.....................................+150NC
Storage Temperature Range............................ -65NC to +150NC
Lead Temperature (soldering, 10s) ................................+300NC
Soldering Temperature (reflow) ......................................+260NC
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional opera-
tion 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
IN
= 3.0V to 5.5V, T
A
= -40NC to +105NC. Typical values are at +5.0V and at T
A
= +25NC. Pin 7 open, unless otherwise noted.)
(Note 1)
PARAMETER
Supply Voltage
Supply Current
Gain-Select Input Current
SYMBOL
V
CC
I
CC
I
IL
T
A
= +25NC
T
A
= -40NC to 105NC
V
IL
= 0V
20
CONDITIONS
MIN
3.0
15.0
25
TYP
MAX
5.5
30
30
100
UNITS
V
mA
FA
AC ELECTRICAL CHARACTERISTICS
(V
CC
= 3.0V to 5.5V, P
IN
= -40dBm, f
IN
= 1575MHz, T
A
= -40NC to +105NC. Typical values are at 5.0V and at T
A
= +25NC. Input
matched to 50I, load = 50I, pin 7 open, unless otherwise noted.) (Note 1)
PARAMETER
Operation Frequency
AMP 1 Gain
AMP 1 Gain Variation Over
Temperature
AMP 1 Noise Figure
AMP 1 Input Third-Order
Intercept Point
AMP 1 Input 1dB Compression
Point
AMP 1 Input Return Loss
AMP 1 Output Return Loss
AMP 1 Reverse Isolation
AMP 2 Gain
AMP 2 Gain Step
AMP 2 Gain Variation Over
Temperature
AMP 2 Noise Figure
NF
(Note 3)
|S
11
|
|S
22
|
|S
12
|
|S
21
|
Gain change when pin 7 is shorted to GND
14.5
-2.5
NF
IIP3
No input match (Notes 2, 3)
Two tones at 1574.5MHz and 1575.5MHz,
-35dBm per tone
50I source with no input match (Note 2)
No input match (Note 2)
SYMBOL
f
RF
|S
21
|
50I source with no input match (Note 2)
50I source with input match
14.5
CONDITIONS
MIN
TYP
1575
16.7
17.8
0.3
1
-12
-19
-4.4
-14.5
-33
17
-3.4
1
2.0
21
-4.0
19
MAX
UNITS
MHz
dB
dB
dB
dBm
dBm
dB
dB
dB
dB
dB
dB
dB
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Maxim Integrated Products
2
MAX2670
GPS/GNSS Front-End Amplifier
AC ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= 3.0V to 5.5V, P
IN
= -40dBm, f
IN
= 1575MHz, T
A
= -40NC to +105NC. Typical values are at 5.0V and at T
A
= +25NC. Input
matched to 50I, load = 50I, pin 7 open, unless otherwise noted.) (Note 1)
PARAMETER
AMP 2 Output Third-Order
Intercept Point
AMP 2 Output 1dB Compression
Point
AMP 2 Input Return Loss
AMP 2 Output Return Loss
AMP 2 Reverse Isolation
|S
11
|
|S
22
|
|S
12
|
SYMBOL
OIP3
CONDITIONS
Two tones at 1574.5MHz and 1575.5MHz,
-30dBm per tone
MIN
TYP
16.0
5.3
-21
-8.8
-25
MAX
UNITS
dBm
dBm
dB
dB
dB
Note 1:
T
A
= +25NC and T
A
= +105NC are guaranteed by production test. At T
A
= -40NC, the minimum and maximum values are
guaranteed by design and characterization, unless otherwise noted.
Note 2:
Measured using the MAX2670 evaluation board with a DC-blocking capacitor at the input of LNA 1.
Note 3:
At T
A
= +25NC, the maximum value is guaranteed by design and characterization. Specification is corrected for board
losses on the MAX2670 EV kit.
Typical Operating Characteristics
(P
IN
= -40dBm, f
IN
= 1575MHz, inputs and outputs are terminated to 50I, V
CC
= 5.0V, T
A
= +25NC, unless otherwise noted.)
AMP 1 NOISE FIGURE vs. TEMPERATURE
(WITHOUT EXTERNAL INPUT IMPEDANCE MATCH)
MAX2670 toc01
AMP 2 NOISE FIGURE vs. TEMPERATURE
MAX2670 toc02
SUPPLY VOLTAGE vs. CURRENT
(PIN 7 OPEN)
27.5
SUPPLY CURRENT (mA)
26.5
25.5
24.5
23.5
22.5
21.5
T
A
= +85°C
T
A
= +105°C
MAX2670 toc03
1.4
1.3
1.2
5.5
5.0
4.5
NOISE FIGURE (dB)
4.0
3.5
3.0
2.5
2.0
1.5
HIGH-GAIN MODE
LOW-GAIN MODE
NOISE FIGURE (dB)
1.1
1.0
0.9
0.8
0.7
0.6
-40
-20
0
20
40
60
80
100
TEMPERATURE (°C)
T
A
= +25°C
T
A
= -40°C
3.0
3.5
4.0
4.5
5.0
5.5
1.0
-40
-20
0
20
40
60
80
100
TEMPERATURE (°C)
SUPPLY VOLTAGE (V)
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Maxim Integrated Products
3
MAX2670
GPS/GNSS Front-End Amplifier
Typical Operating Characteristics (continued)
(P
IN
= -40dBm, f
IN
= 1575MHz, inputs and outputs are terminated to 50I, V
CC
= 5.0V, T
A
= +25NC, unless otherwise noted.)
AMP 1 GAIN vs. SUPPLY VOLTAGE
(WITH EXTERNAL INPUT IMPEDANCE MATCH)
MAX2670 toc04
AMP 2 GAIN vs. SUPPLY VOLTAGE
(PIN 7 OPEN)
MAX2670 toc05
AMP 2 GAIN vs. SUPPLY VOLTAGE
(PIN 7 SHORT TO GND)
MAX2670 toc06
18.1
18.0
17.9
GAIN (dB)
17.8
17.7
17.6
17.5
17.4
17.3
3.0
3.5
4.0
4.5
5.0
T
A
= +105°C
T
A
= +85°C
T
A
= -40°C
T
A
= +25°C
18.0
17.5
T
A
= -40°C
GAIN (dB)
17.0
T
A
= +25°C
16.5
T
A
= +85°C
16.0
15.5
T
A
= +105°C
15.0
14.5
14.0
GAIN (dB)
13.5
13.0
12.5
12.0
T
A
= -40°C
T
A
= +25°C
T
A
= +85°C
T
A
= +105°C
3.0
3.5
4.0
4.5
5.0
5.5
3.0
3.5
4.0
4.5
5.0
5.5
5.5
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
AMP 1 GAIN vs. FREQUENCY
(WITH EXTERNAL INPUT IMPEDANCE MATCH)
MAX2670 toc07
AMP 2 GAIN vs. FREQUENCY
MAX2670 toc08
AMP 1 INPUT P
1dB
vs. TEMPERATURE
(WITHOUT EXTERNAL INPUT IMPEDANCE MATCH)
MAX2670 toc09
20
19
18
GAIN (dB)
18
16
14
12
GAIN (dB)
10
8
6
4
2
0
LOW-GAIN MODE
HIGH-GAIN MODE
-16
-17
17
16
15
14
13
12
800
1000
1200
1400
1600
1800
2000
FREQUENCY (MHz)
INPUT P
1dB
(dBm)
1800
2000
-18
-19
-20
-21
-22
800
1000
1200
1400
1600
-40
-20
0
20
40
60
80
100
FREQUENCY (MHz)
TEMPERATURE (°C)
AMP 2 OUTPUT P
1dB
vs. TEMPERATURE
(PIN 7 OPEN)
MAX2670 toc10
AMP 1 S11
(WITHOUT EXTERNAL INPUT IMPEDANCE MATCH)
MAX2670 toc11
AMP 1 S22
MAX2670 toc12
5.8
5.6
OUTPUT P
1dB
(dB)
5.4
5.2
5.0
4.8
-40
-20
0
20
40
60
80
100
TEMPERATURE (°C)
-2.0
-2.5
-3.0
S11 (dB)
-4
-6
-8
S22 (dB)
-10
-12
-14
-16
-3.5
-4.0
-4.5
-5.0
800
1000
1200
1400
1600
1800
2000
FREQUENCY (MHz)
800
1000
1200
1400
1600
1800
2000
FREQUENCY (MHz)
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Maxim Integrated Products
4
MAX2670
GPS/GNSS Front-End Amplifier
Typical Operating Characteristics (continued)
(P
IN
= -40dBm, f
IN
= 1575MHz, inputs and outputs are terminated to 50I, V
CC
= 5.0V, T
A
= +25NC, unless otherwise noted.)
AMP 2 S11
MAX2670 toc13
AMP 2 S22
-6
-8
-10
MAX2670 toc14
0
-5
-10
-15
-20
-25
800
-4
S11 (dB)
S22 (dB)
1000
1200
1400
1600
1800
2000
-12
-14
-16
-18
-20
-22
800
1000
1200
1400
1600
1800
2000
FREQUENCY (MHz)
FREQUENCY (MHz)
AMP 1 S12
MAX2670 toc15
AMP 2 S12
MAX2670 toc16
-32
-20
-24
-28
-32
-36
-40
800
-34
S12 (dB)
S12 (dB)
-36
-38
-40
800
1000
1200
1400
1600
1800
2000
1000
1200
1400
1600
1800
2000
FREQUENCY (MHz)
FREQUENCY (MHz)
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Maxim Integrated Products
5
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