General Description
The MAX12000 GPS front-end amplifier IC is designed
for automotive and marine GPS satellite navigation
antenna modules or for any application that needs to
compensate for cable losses from the GPS 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 MAX12000 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 performance of the GPS receiver. Additionally, a
3.4dB gain step is provided to compensate for cable
loss variation between different applications.
The MAX12000 is designed to operate at the GPS frequency of 1575MHz with a 34.8dB typical cascaded
gain and a 25mA supply current. The two LNA stages
allow the use of a wide range of GPS filter types for
maximum flexibility in system design. The final RF output pin, which drives the cable to the GPS 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.
The GPS 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).
Applications
Integrated Automotive and Marine GPS
Receivers
Features
♦ First Amp Noise Figure*: 1.0dB
♦ High Gain**: 34.8dB
♦ 3.4dB Gain Step
♦ Integrated 50Ω Output Matching
♦ 3.0V to 5.5V Supply Voltage Range
♦ Small, Low-Cost Package (3mm x 3mm)
♦ ESD Protected to ±1kV Human Body Model
MAX12000
1575MHz GPS Front-End Amplifier
________________________________________________________________ Maxim Integrated Products 1
1
+
3
4
10
8
7
RFOUT1
DC
GENERATION
GND
GAIN_SELECT
RFIN2
GND
EXTCAP/ALT_V
CC
MAX12000
29
GNDGND
56
RFIN1RFOUT2/V
CC
TDFN
TOP VIEW
AMP 2
AMP 1
Pin Configuration/Functional Diagram
Ordering Information
19-4021; Rev 0; 3/06
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.
+Denotes lead-free package.
Typical Operating Circuit appears at end of data sheet.
*Without external input impedance match.
**First amplifier input is impedance matched (S11= -10dB).
Second amplifier set to high gain. Amplifiers cascaded without
interstage filter.
EVALUATION KIT
AVAILABLE
PART
TEMP RANGE
PIN-
PKG
CODE
10 TDFN
T1033-2
PACKAGE
MAX12000ETB+ -40°C to +85°C
MAX12000
1575MHz GPS Front-End Amplifier
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
DC ELECTRICAL CHARACTERISTICS
(VCC= +3.0V to +5.5V, TA= -40°C to +85°C. Typical values are at +5.0V and at TA= +25°C. Pin 7 open, unless otherwise noted.) (Note 1)
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.
RFOUT1, RFOUT2, EXTCAP to GND...........-0.3V to (VCC+ 0.5V)
RFIN1 Input Power (50Ω source) ...................................+15dBm
RFIN1 to GND........................................................-0.3V to +0.3V
RFIN2 to GND........................................................-0.3V to +1.0V
GAIN_SELECT to GND...............................-0.3V to (V
CC
+ 0.3V)
Continuous Power Dissipation (T
A
= +70°C)
10-Pin TDFN (derate 18.5mW/°C above +70°C) ........1481mW
Operating Ambient Temperature Range ...........-40°C to +105°C
Maximum Junction Temperature .....................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
CAUTION! ESD SENSITIVE DEVICE
PARAMETER
CONDITIONS
UNITS
Supply Voltage V
CC
3.0 5.5 V
TA = +25°C
25
Supply Current I
CC
TA = -40°C to 105°C (Note 2) 33
mA
Gain-Select Input Current I
IL
VIL = 0V 20 100 µA
AC ELECTRICAL CHARACTERISTICS
(VCC= +3.0V to +5.5V, PIN= -40dBm, fIN= 1575MHz, TA= -40°C to +85°C. Typical values are at +5.0V and at TA= +25°C. Input
matched to 50Ω, load = 50Ω, pin 7 open, unless otherwise noted.) (Note 1)
PARAMETER
CONDITIONS
UNITS
Operation Frequency f
RF
MHz
50Ω source with no input match (Note 3)
AMP 1 Gain ⏐S21⏐
50Ω source with input match
dB
AMP 1 Gain Variation Over
Temperature
0.3 dB
AMP 1 Noise Figure NF No input match (Notes 3, 4) 1 1.3 dB
AMP 1 Input Third-Order
Intercept Point
IIP3
Two tones at 1574.5MHz and 1575.5MHz,
-35dBm per tone
-12
dBm
AMP 1 Input 1dB Compression
Point
50Ω source with no input match (Note 3) -19
dBm
AMP 1 Input Return Loss ⏐S11⏐ No input match (Note 3)
dB
AMP 1 Output Return Loss ⏐S22⏐
dB
AMP 1 Reverse Isolation ⏐S12⏐ -33 dB
AMP 2 Gain ⏐S21⏐
17
dB
AMP 2 Gain Step
dB
AMP 2 Gain Variation Over
Temperature
1dB
AMP 2 Noise Figure NF (Note 4) 2.0 2.4 dB
AMP 2 Output Third-Order
Intercept Point
OIP3
Two tones at 1574.5MHz and 1575.5MHz,
-30dBm per tone
dBm
AMP 2 Output 1dB Compression
Point
1.5 5.3
dBm
SYMBOL
MIN TYP MAX
15.0
SYMBOL
Gain change when pin 7 is shorted to GND -2.8 -3.4 -4.0
MIN TYP MAX
1575
15.0 16.7 18.5
17.8
15.0
-4.4
-14.5
16.0
30.2
19.6
MAX12000
1575MHz GPS Front-End Amplifier
_______________________________________________________________________________________ 3
0.6
0.8
0.7
1.0
0.9
1.1
1.2
1.3
1.4
-40 0 20-20 406080100
AMP 1 NOISE FIGURE vs. TEMPERATURE
(WITHOUT EXTERNAL INPUT IMPEDANCE MATCH)
MAX12000 toc01
TEMPERATURE (°C)
NOISE FIGURE (dB)
1.0
2.0
1.5
3.0
2.5
3.5
4.0
4.5
5.5
5.0
-40 0 20-20 40 60 80 100
AMP 2 NOISE FIGURE vs. TEMPERATURE
MAX12000 toc02
TEMPERATURE (°C)
NOISE FIGURE (dB)
LOW-GAIN MODE
HIGH-GAIN MODE
22.5
21.5
24.5
23.5
26.5
25.5
27.5
3.0 4.03.5 4.5 5.0 5.5
SUPPLY VOLTAGE vs. CURRENT
(PIN 7 OPEN)
MAX12000 toc03
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
TA = +105°C
TA = +85°C
TA = +25°C
TA = -40°C
17.4
17.3
17.6
17.5
17.8
17.7
17.9
18.0
18.1
3.0 4.03.5 4.5 5.0 5.5
AMP 1 GAIN vs. SUPPLY VOLTAGE
(WITH EXTERNAL INPUT IMPEDANCE MATCH)
MAX12000 toc04
SUPPLY VOLTAGE (V)
GAIN (dB)
TA = +105°C
TA = +85°C
TA = +25°C
TA = -40°C
16.0
15.5
17.0
16.5
18.0
17.5
3.0 4.03.5 4.5 5.0 5.5
AMP 2 GAIN vs. SUPPLY VOLTAGE
(PIN 7 OPEN)
MAX12000 toc05
SUPPLY VOLTAGE (V)
GAIN (dB)
TA = +105°C
TA = +85°C
TA = +25°C
TA = -40°C
13.0
12.5
12.0
14.0
13.5
15.0
14.5
3.0 4.03.5 4.5 5.0 5.5
AMP 2 GAIN vs. SUPPLY VOLTAGE
(PIN 7 SHORT TO GND)
MAX12000 toc06
SUPPLY VOLTAGE (V)
GAIN (dB)
TA = +105°C
TA = +85°C
TA = +25°C
TA = -40°C
Typical Operating Characteristics
(PIN= -40dBm, fIN= 1575MHz, inputs and outputs are terminated to 50Ω, VCC= +5.0V, TA= +25°C, unless otherwise noted.)
Note 1: At T
A
= -40°C, the minimum and maximum values are guaranteed by design and characterization, unless otherwise noted.
Note 2: At T
A
= -40°C and +105°C, the maximum value is guaranteed by design and characterization.
Note 3: Measured using MAX12000 evaluation board with a DC-blocking capacitor at the input of LNA 1.
Note 4: At T
A
= +25°C, the maximum value is guaranteed by design and characterization. Specification is corrected for board
losses on the MAX12000 EV kit.
AC ELECTRICAL CHARACTERISTICS (continued)
(VCC= +3.0V to +5.5V, PIN= -40dBm, fIN= 1575MHz, TA= -40°C to +85°C. Typical values are at +5.0V and at TA= +25°C. Input
matched to 50Ω, load = 50Ω, pin 7 open, unless otherwise noted.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
AMP 2 Input Return Loss ⏐S11⏐ -21 dB
AMP 2 Output Return Loss ⏐S22⏐
dB
AMP 2 Reverse Isolation ⏐S12⏐ -25 dB
-8.8
MAX12000
1575MHz GPS Front-End Amplifier
4 _______________________________________________________________________________________
13
12
15
14
17
16
18
19
20
800 12001000 1400 1600 1800 2000
AMP 1 GAIN vs. FREQUENCY
(WITH EXTERNAL INPUT IMPEDANCE MATCH)
MAX12000 toc07
FREQUENCY (MHz)
GAIN (dB)
2
0
6
4
10
8
12
14
16
18
800 12001000 1400 1600 1800 2000
AMP 2 GAIN vs. FREQUENCY
MAX12000 toc08
FREQUENCY (MHz)
GAIN (dB)
LOW-GAIN MODE
HIGH-GAIN MODE
-22
-20
-21
-19
-18
-17
-16
-40 0 20-20 40 60 80 100
AMP 1 INPUT P
1dB
vs. TEMPERATURE
(WITHOUT EXTERNAL INPUT IMPEDANCE MATCH)
MAX12000 toc09
TEMPERATURE (°C)
INPUT P
1dB
(dBm)
4.8
5.2
5.0
5.4
5.6
5.8
-40 0 20-20 40 60 80 100
AMP 2 OUTPUT P
1dB
vs. TEMPERATURE
(PIN 7 OPEN)
MAX12000 toc10
TEMPERATURE (°C)
OUTPUT P
1dB
(dB)
-4.5
-5.0
-3.5
-4.0
-2.5
-3.0
-2.0
800 12001000 1400 1600 1800 2000
AMP 1 S11
(WITHOUT EXTERNAL INPUT IMPEDANCE MATCH)
MAX12000 toc11
FREQUENCY (MHz)
S11 (dB)
-14
-16
-10
-12
-6
-8
-4
800 12001000 1400 1600 1800 2000
AMP 1 S22
MAX12000 toc12
FREQUENCY (MHz)
S22 (dB)
-15
-10
-25
-20
-5
0
800 12001000 1400 1600 1800 2000
AMP 2 S11
MAX12000 toc13
FREQUENCY (MHz)
S11 (dB)
-14
-16
-10
-12
-20
-22
-18
-6
-8
-4
800 12001000 1400 1600 1800 2000
AMP 2 S22
MAX12000 toc14
FREQUENCY (MHz)
S22 (dB)
Typical Operating Characteristics (continued)
(PIN= -40dBm, fIN= 1575MHz, inputs and outputs are terminated to 50Ω, VCC= +5.0V, TA= +25°C, unless otherwise noted.)
MAX12000
1575MHz GPS Front-End Amplifier
_______________________________________________________________________________________ 5
-36
-34
-40
-38
-32
800 12001000 1400 1600 1800 2000
AMP 1 S12
MAX12000 toc15
FREQUENCY (MHz)
S12 (dB)
-28
-24
-36
-40
-32
-20
800 12001000 1400 1600 1800 2000
AMP 2 S12
MAX12000 toc16
FREQUENCY (MHz)
S12 (dB)
Pin Description
Typical Operating Characteristics (continued)
(PIN= -40dBm, fIN= 1575MHz, inputs and outputs are terminated to 50Ω, VCC= +5.0V, TA= +25°C, unless otherwise noted.)
PIN NAME FUNCTION
1 RFIN2
Amplifier 2 Input. Incorporates an internal DC-blocking capacitor and is internally matched to 50Ω.
This input is designed to be connected to a bandpass filter.
2, 3, 8, 9
GND Electrical Ground
4
EXTCAP/
ALT_V
CC
External Smoothing Capacitor for Internal Supply Voltage or Can Be Used as the External DC Supply
Pin to Eliminate the Need for a Bias-T on Pin 5
5
Amplifier 2 Output. Incorporates an internal DC-blocking capacitor and is internally matched to 50Ω.
DC bias on this pin serves as the power supply through a bias-T.
6 RFIN1 Amplifier 1 Input. Requires external DC-blocking capacitor and matching components.
7
AMP 2 Gain Select. Open is high-gain mode. Short to ground is low-gain mode.
10 RFOUT1
Amplifier 1 Output. Incorporates an internal DC-blocking capacitor and is internally matched to 50Ω.
This output is designed to drive a bandpass filter.
EP
Ground. The exposed pad must be soldered to the circuit board for proper thermal and electrical
performance.
RFOUT2/V
CC
GAIN_SELECT
Exposed Pad
MAX12000
Detailed Description
The MAX12000 IC contains two LNA stages tuned for
use at 1575MHz.
AMP 1
AMP 1 has an internal load that limits the bandwidth
and provides a 50Ω output impedance through a DCblocking capacitor. The internal biasing for AMP 1 suppresses gain variation with changes in temperature and
supply voltage. At the input, an integrated DC-blocking
capacitor and matching network are intentionally omitted to allow selection of external components to optimize for noise or gain.
AMP 2 with Gain Step
The output of AMP 2 has the dual role of providing both
the RF output drive and receiving the DC power supply
through a single cable. Both the input and output ports
of AMP 2 are internally matched to 50Ω impedance at
1575MHz. A 3.4dB gain switch can be used to adjust
the gain for different applications. The gain-select pin is
connected to an inverter with an internal pullup resistor.
Hence, the gain-select pin is set by default to high-gain
mode. Shorting the gain-select pin to ground sets the
gain stage to a 3.4dB lower gain. As with AMP 1, AMP
2 has an internal load that limits the bandwidth, and the
amplifier’s internal biasing suppresses gain variation
with changes in temperature and supply voltage.
Supply
The IC power can be supplied from the navigation system through the RF cable (pin 5). An integrated filter
circuit is connected to the output of LNA 2 to separate
the supply voltage from the GPS signal. Alternatively,
the supply voltage can be applied to the external
capacitor pin (pin 4).
Layout Considerations
For best performance, carefully lay out the printed circuit board using high-frequency techniques. Use controlled-impedance transmission lines to interface with
the MAX12000 high-speed inputs and outputs and isolate the input signals from the output signals as much
as possible. For improved noise figure, keep the connection to the input of LNA 1 as short as possible. A
power-supply decoupling capacitor should be placed
very close to pin 4 and connected directly to a ground
plane. If low-gain selection for LNA 2 is required, connect pin 7 directly to the ground plane with a very short
printed circuit board trace. Good grounding is critical
for this device. The backside ground plane should be
as close as possible. See Figure 1 for printed circuit
board layout.
1575MHz GPS Front-End Amplifier
6 _______________________________________________________________________________________
1
2/3
4
5
6
7
8/9
10
SAW
V
CC
REG
V
CC
REG
LNA 2
OUTPUT
GAIN SETTING
OPEN = 31.4dB GAIN
SHORT TO GROUND = 28dB GAIN
PINNING:
1 = LNA 2 INPUT
2 = GND
3 = GND
4 = EXTCAP/ALT_V
CC
5 = LNA 2 OUTPUT/V
CC
6 = LNA 1 INPUT
7 = GAIN SETTING
8 = GND
9 = GND
10 = LNA 1 OUTPUT
LNA 1
MATCHING
NETWORK/
DC BLOCK
EXPOSED PADDLE
MAX12000
Typical Operating Circuit
MAX12000
1575MHz GPS Front-End Amplifier
_______________________________________________________________________________________ 7
Figure 1. Layout of the Evaluation Board Realized on 0.8mm FR4 (Not to Scale)
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
.)
6, 8, &10L, DFN THIN.EPS
L
C
L
C
PIN 1
INDEX
AREA
D
E
L
e
L
A
e
E2
N
G
1
2
21-0137
PACKAGE OUTLINE, 6,8,10 & 14L,
TDFN, EXPOSED PAD, 3x3x0.80 mm
-DRAWING NOT TO SCALE-
k
e
[(N/2)-1] x e
REF.
PIN 1 ID
0.35x0.35
DETAIL A
b
D2
A2
A1
MAX12000
1575MHz GPS Front-End Amplifier
8 _______________________________________________________________________________________
MAX12000
1575MHz GPS Front-End Amplifier
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 _____________________ 9
© 2006 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products, Inc.
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
.)
COMMON DIMENSIONS
SYMBOL
MIN. MAX.
A
0.70 0.80
D
2.90 3.10
E
2.90 3.10
A1
0.00 0.05
L
0.20 0.40
PKG. CODE
N
D2 E2 e
JEDEC SPEC
b
[(N/2)-1] x e
PACKAGE VARIATIONS
0.25 MIN.k
A2 0.20 REF.
2.30±0.101.50±0.106T633-1 0.95 BSC MO229 / WEEA 1.90 REF0.40±0.05
1.95 REF0.30±0.05
0.65 BSC
2.30±0.108T833-1
2.00 REF0.25±0.05
0.50 BSC
2.30±0.1010T1033-1
2.40 REF0.20±0.05- - - -
0.40 BSC
1.70±0.10 2.30±0.1014T1433-1
1.50±0.10
1.50±0.10
MO229 / WEEC
MO229 / WEED-3
0.40 BSC
- - - - 0.20±0.05 2.40 REFT1433-2 14 2.30±0.101.70±0.10
T633-2 6 1.50±0.10 2.30±0.10 0.95 BSC
MO229 / WEEA
0.40±0.05 1.90 REF
T833-2 8 1.50±0.10 2.30±0.10
0.65 BSC MO229 / WEEC
0.30±0.05 1.95 REF
T833-3 8 1.50±0.10 2.30±0.10
0.65 BSC MO229 / WEEC
0.30±0.05 1.95 REF
-DRAWING NOT TO SCALE-
G
2
2
21-0137
PACKAGE OUTLINE, 6,8,10 & 14L,
TDFN, EXPOSED PAD, 3x3x0.80 mm
DOWNBONDS
ALLOWED
NO
NO
NO
NO
YES
NO
YES
NO
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