Rainbow Electronics MAX2670 User Manual

E V A L U A T I O N K IT A V A I L A B L E

19-5655; Rev 0; 6/11

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 performance of the GPS/GNSS receiver. Additionally, a 3.4dB gain step is provided to compensate for cable loss variation between different applications.

The device is designed to operate across all GNSS frequency 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 maximum 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 lownoise, advanced SiGe process and is available in a leadfree, 10-pin TDFN surface-mount package (3mm x 3mm).

Features

S First Amplifier Noise Figure*: 1.0dB

S High Gain**: 34.8dB

S 3.4dB Gain Step

S Shared V

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

Applications

Integrated Automotive and Marine GPS Receivers

Active Antennas

*Without external input impedance match. **First amplifier input is impedance matched (S11 = -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

2 9

GND

EXTCAP/ALT_VCC

For related parts and recommended products to use with this part, refer to www.maxim-ic.com/MAX2670.related.

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5 6

MAX2670

AMP 2

AMP 1

GENERATION

TDFN

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.

RFOUT1

GNDGND

GND

GAIN_SELECT

RFIN1RFOUT2/VCC

MAX2670

GPS/GNSS Front-End Amplifier

ABSOLUTE MAXIMUM RATINGS

RFOUT1, RFOUT2, EXTCAP to GND ....... -0.3V to (VCC + 0.5V)

RFIN1 Input Power (50I source) .................................. +15dBm

GAIN_SELECT to GND ............................. -0.3V to (VCC + 0.3V)

Continuous Power Dissipation (TA = +70NC)

TDFN (derate 18.5mW/NC above +70NC) ..................1481mW

Operating Ambient Temperature Range .........-40NC to +105NC

Maximum Junction Temperature .....................................+150NC

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

(VIN = 3.0V to 5.5V, TA = -40NC to +105NC. Typical values are at +5.0V and at TA = +25NC. Pin 7 open, unless otherwise noted.) (Note 1)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Supply Voltage V

Supply Current I

Gain-Select Input Current I

3.0 5.5 V

TA = +25NC

TA = -40NC to 105NC

VIL = 0V 20 100

Storage Temperature Range ............................ -65NC to +150NC

Lead Temperature (soldering, 10s) ................................+300NC

Soldering Temperature (reflow) ......................................+260NC

15.0 25 30

AC ELECTRICAL CHARACTERISTICS

(VCC = 3.0V to 5.5V, PIN = -40dBm, fIN = 1575MHz, TA = -40NC to +105NC. Typical values are at 5.0V and at TA = +25NC. Input matched to 50I, load = 50I, pin 7 open, unless otherwise noted.) (Note 1)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Operation Frequency f

AMP 1 Gain

AMP 1 Gain Variation Over Temperature

AMP 1 Noise Figure NF No input match (Notes 2, 3) 1 dB

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 Gain change when pin 7 is shorted to GND -2.5 -3.4 -4.0 dB

AMP 2 Gain Variation Over Temperature

AMP 2 Noise Figure NF (Note 3) 2.0 dB

|S21|

IIP3

|S11|

|S22|

|S12|

|S21|

50I source with no input match (Note 2) 50I source with input match

Two tones at 1574.5MHz and 1575.5MHz,

-35dBm per tone

50I source with no input match (Note 2)

No input match (Note 2) -4.4 dB

14.5 16.7 19

14.5 17 21 dB

1575 MHz

17.8

0.3 dB

-12 dBm

-19 dBm

-14.5 dB

-33 dB

1 dB

�� Maxim Integrated Products 2

MAX2670

(WITHOUT EXTERNAL INPUT IMPEDANCE MATCH)

NOISE FIGURE (dB)

GPS/GNSS Front-End Amplifier

AC ELECTRICAL CHARACTERISTICS (continued)

(VCC = 3.0V to 5.5V, PIN = -40dBm, fIN = 1575MHz, TA = -40NC to +105NC. Typical values are at 5.0V and at TA = +25NC. Input matched to 50I, load = 50I, pin 7 open, unless otherwise noted.) (Note 1)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

AMP 2 Output Third-Order Intercept Point

OIP3

AMP 2 Output 1dB Compression Point

AMP 2 Input Return Loss

AMP 2 Output Return Loss

AMP 2 Reverse Isolation

|S11|

|S22|

|S12|

Note 1: TA = +25NC and TA = +105NC are guaranteed by production test. At TA = -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 TA = +25NC, the maximum value is guaranteed by design and characterization. Specification is corrected for board

losses on the MAX2670 EV kit.

Two tones at 1574.5MHz and 1575.5MHz,

-30dBm per tone

16.0 dBm

5.3 dBm

-21 dB

-8.8 dB

-25 dB

(PIN = -40dBm, fIN = 1575MHz, inputs and outputs are terminated to 50I, VCC = 5.0V, TA = +25NC, unless otherwise noted.)

AMP 1 NOISE FIGURE vs. TEMPERATURE

1.4

1.3

1.2

1.1

1.0

0.9

0.8

0.7

0.6

-40 0 20-20 40 60 80 100

TEMPERATURE (°C)

MAX2670 toc01

Typical Operating Characteristics

AMP 2 NOISE FIGURE vs. TEMPERATURE

5.5

5.0

4.5

4.0

3.5

3.0

NOISE FIGURE (dB)

2.5

2.0

1.5

1.0

-40 0 20-20 40 60 80 100

TEMPERATURE (°C)

LOW-GAIN MODE

HIGH-GAIN MODE

27.5

MAX2670 toc02

26.5

25.5

24.5

23.5

SUPPLY CURRENT (mA)

22.5

21.5

SUPPLY VOLTAGE vs. CURRENT

(PIN 7 OPEN)

TA = +105°C

MAX2670 toc03

TA = +85°C

TA = +25°C

TA = -40°C

3.0 4.03.5 4.5 5.0 5.5

SUPPLY VOLTAGE (V)

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