Rainbow Electronics MAX2740 User Manual

General Description

The MAX2740 is a complete global positioning system
(GPS) receiver from antenna output to digitizer input.
The signal path includes the LNA, two downconverters,
and variable-gain and fixed-gain amplifiers. By utilizing
a double-conversion superheterodyne architecture with
external surface acoustic wave (SAW) filters, high levels
of image rejection and blocking immunity are possible.
Receiver linearity has been maximized to improve oper­ation in hostile RFI environments found in cellular base
stations. The MAX2740 also includes a high-perfor­mance voltage-controlled oscillator (VCO) with low
phase noise for subcentimeter carrier phase applica­tions, and a fixed-frequency synthesizer for generation
of all required on-chip local oscillators.

The unique frequency plan captured in the MAX2740 is
suitable for joint GPS/GLONASS receivers with minimal
external components. This allows the MAX2740 to pro­vide a cost-effective and high-performance solution for
navigation and timing products that need maximum
satellite availability.

The MAX2740 is compatible with a high-performance
DSP engine capable of very fast time to first fix and
excellent multipath rejection.

________________________Applications

Base Station Timing

E911 Location Assistance

GPS Automotive and Consumer Receivers

Wireless Local-Loop Timing

Joint GPS/GLONASS Receivers

High-Precision Timing for SDH Networks

High-Positional-Accuracy Surveying Equipment

Features

♦ High Selectivity for Hostile Base Station

Environments

♦ Complete Antenna-to-Baseband Receiver

Solution

♦ >100dB Total Receiver Gain Including All Filter

Losses

♦ >50dB Automatic Gain Control (AGC) Range

♦ Fully Balanced Topology for Minimum Spurious

Responses

♦ Low Phase Noise VCO for Carrier Phase

Applications

♦ Compatible with High-Performance Companion

DSP

MAX2740

Integrated GPS Receiver and Synthesizer

________________________________________________________________ Maxim Integrated Products 1

Pin Configuration/

Functional Diagram

19-1670; Rev 0; 4/00

For free samples and the latest literature, visit www.maxim-ic.com or phone [phone].
For small orders, phone [phone].

Ordering Information

48 TQFP-EP*

PIN-PACKAGETEMP. RANGE

-40°C to +85°CMAX2740ECM

PART

*Exposed paddle

LNA_OUT

GND

RFMIX_IN+

VCC_RFMIX

RFMIX_OUT+

RFMIX_OUT-

GND

GND

VCC_IFMIX

IFMIX_IN+

IFMIX_IN-

GND

GND
GND

LNA_IN

GND
GND
GND

RFMIX_IN-

VCC_ANA

GND
GND

VCC_VCO

4847464544434241403938

1

2

3

4

5

6

7

GC

8

9

10

11

12

MAX2740

/2 /6

/8

/6

PFD

37

36

IFMIX_OUT+

35

IFMIX_OUT-

34

VGA_IN+

33

VGA_IN­GND

32

VGA_OUT+

31

VGA_OUT-

30

GND

29

FGA_IN+

28

FGA_IN-

27

GND

26

FGA_OUT+

25

48

TQFP

ACTUAL SIZE

9mm x 9mm

1314151617181920212223

TANK

GND

GND

UP

DOWN

VCC_DIG

TQFP-EP

REF_IN

GLS_OUT

GND

GND

24

GND

FGA_OUT-

MAX2740

Integrated GPS Receiver and Synthesizer

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

DC ELECTRICAL CHARACTERISTICS

(VCC= +2.7V to +3.3V, TA= -40°C to +85°C. Typical values are at VCC= +3.0, TA= +25°C.)

AC ELECTRICAL CHARACTERISTICS

(MAX2740 EV kit, VCC= +3.0V, 50Ω system impedance, FRF= 1575.42MHz, F

IF1

= 135.42MHz, F

IF2

= 15.42MHz, F

REF

= 20MHz at

600mVpp, T

A

= +25°C, unless otherwise noted.)

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.

VCCPins to GND ...................................................-0.3V to +4.3V

RF LNA Input Power .......................................................+10dBm

LO Input Power...............................................................+10dBm

GC Input Voltage ..........................................-0.3 to (V

CC

+ 0.3V)

Continuous Power Dissipation (T

A

= +85°C)

48-Pin TQFP-EP Package ...........................................800mW

Operating Temperature Range ...........................-40°C to +85°C

Junction Temperature......................................................+150°C

Storage Temperature Range .............................-65°C to +160°C

Lead Temperature (soldering, 10s) .................................+300°C

Total Supply Current 55.1 84.3 mA

AGC Voltage Range

AGC Current -50 +25 µA

PARAMETER CONDITIONS MIN TYP MAX UNITS

0.5 to

2.5

V

LNA

LNA Gain (Note 1) 13.1 16.0 17.2 dB

LNA Gain Variation Over
Temperature

LNA Input Third-Order Intercept
Point

LNA Noise Figure 2.6 dB

RF MIXER (Zl = 100Ω differential)

RF Mixer Conversion Gain (Note 3) 22.6 dB

RF Mixer Input IP3 -22.4 dBm

RF Mixer Noise Figure (SSB) 11.0 dB

IF MIXER (Z

IF Mixer Conversion Gain 36.3 dB

VARIABLE-GAIN AMPLIFIER (VGA) (Z

VGA Voltage Gain at Maximum
Gain Setting

VGA Voltage Gain at Minimum
Gain Setting

FIXED GAIN AMPLIFIER (FGA)

FGA Voltage Gain Z

FGA 1dB Compression (Output)

PARAMETER CONDITIONS MIN TYP MAX UNITS

Relative to ambient (Note 1) -1.3 ±0.5 +1.0 dB

(Note 2) -9.4 dBm

= 100Ω differential, Z

s

= 4kΩ differential)

l

= 4kΩ differential)

l

GC = 2.5V 15.1 dB

GC = 0.5V -54.7 dB

= 4kΩ differential 39.8 dB

l

2.05 Vp-p

MAX2740

Integrated GPS Receiver and Synthesizer

_______________________________________________________________________________________ 3

GAIN

(dB)

Typical Operating Characteristics

(TA = +25°C, unless otherwise noted.)

Note 1: Guaranteed by design and characterization.
Note 2: Two tones at pin = -35dBm per tone, f1 = 1575MHz, f2 = 1576MHz.
Note 3: Two tones at pin = -40dBm per tone, f1 = 1575MHz, f2 = 1576MHz.

AC ELECTRICAL CHARACTERISTICS (continued)

(MAX2740 EV kit, VCC= +3.0V, 50Ω system impedance, FRF= 1575.42MHz, F

IF1

= 135.42MHz, F

IF2

= 15.42MHz, F

REF

= 20MHz at

600mVpp, T

A

= +25°C, unless otherwise noted.)

PARAMETER CONDITIONS MIN TYP MAX UNITS

VOLTAGE-CONTROLLED OSCILLATOR (VCO) (100kHz offset)

Synthesizer VCO Phase Noise -91.5 dBc/Hz

Output Frequency for External
GLONASS Tuner

Magnitude GLS_OUT Rl = 500Ω, Cl = 10pF 300 mVp-p

PFD Swing on Up and Down
Outputs

Mag (UP-DOWN) 250 mV

VCC = 3.0V

40 50

20 30

ICC vs. TEMPERATURE AND V

70

60

VCC = 3.3V

50

VCC = 2.7V

40

30

CURRENT (mA)

20

10

0

-40 -30

-20

010

-10 60
TEMPERATURE (°C)

20 30

CC

VCC = 3.0V

40 50

LNA GAIN vs. TEMPERATURE AND V

20

VCC = 3.3V

18

16

MAX2740-01

14

VCC = 2.7V

12

10

8

6

4

2

0

-40 -30

-20

010

-10 60

8070

TEMPERATURE (°C)

CC

MAX2740-02

8070

25

20

15

GAIN (dB)

10

5

0

90 MHz

RF MIXER GAIN

vs. TEMPERATURE AND V

VCC = 3.3V

VCC = 3.0V

-40 -30

-20

010

-10 60

TEMPERATURE (°C)

20 30

VCC = 2.7V

40 50

CC

MAX2740-06

8070

40

35

30

25

20

GAIN (dB)

15

10

5

0

IF MIXER GAIN vs.

TEMPERATURE AND V

-40 -30

-20

-10 60

VGA GAIN vs. VGC AND

CC

= 3.0V

2.2

FGA GAIN vs. TEMPERATURE AND V

45

40

MAX2740-04

35

30

25

20

GAIN (dB)

15

10

5

2.4

0

-40 -30

-20

-10 60

VCC = 2.7V

= 3.3V

V

CC

= 3.0V

V

CC

010

TEMPERATURE (°C)

20 30

40 50

VCC = 2.7V

= 3.3V

V

CC

= 3.0V

V

CC

010

TEMPERATURE (°C)

20 30

40 50

CC

MAX2740-03

VGA GAIN (dB)

8070

TEMPERATURE AT V

30

20

10

0

-10

-20

-30

-40

-50

-60

1.0 1.2 1.4 1.6 1.8 2.0

TA = +25°C
T

A

T

A

AGC CONTROL VOLTAGE (V)

= +85°C
= -40°C

CC

MAX2740-05

8070