MAX2741 Просмотр технического описания (PDF) - Maxim Integrated

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производитель

MAX2741

Integrated L1-Band GPS Receiver

Maxim Integrated 

MAX2741

Integrated L1-Band GPS Receiver

Pin Description

PIN

1

2, 20, 22, 23

NAME

VCC1

N.C.

3

RFIN

4

VCC2

5

VCC3

6

VCC4

7

GND

8

FILT

9

SCLK

10

CS

11

SDI

12

SHDN

13

XTAL

14

REFCLK

15

GPSCLK

16

GPSIF2

17

GPSIF1

18

GPSIF0

19

VCC5

21

SDO

24

IFIN-

25

IFIN+

26

27

28

Exposed

Paddle

IFOUT-

IFOUT+

VCC6

GND

FUNCTION

LNA Supply Connection. External RF bypass capacitor to ground required.

Reserved. Make no connections to this pin.

LNA Input. Connect to GPS antenna through a bandpass filter. This input requires an external

matching network to match to 50Ω. AC-couple to this pin.

VCO Supply Connection. External RF bypass capacitor to ground required.

CML Supply Connection. External RF bypass capacitor to ground required.

Digital Logic and PLL Supply Connection. External RF bypass capacitor to digital ground required.

Ground. Connect to PC board digital ground plane.

PLL Loop Filter Connection. This is the output of the phase detector’s charge pump. Use the

recommended filter on EV kit for optimal phase noise and lock time.

SPI Clock Input (CMOS)

SPI Chip-Select Input (CMOS, Active Low)

SPI Data Input (CMOS)

Full IC Power-Down. This shutdown pin disables the on-chip oscillator and the rest of the IC. To keep

the oscillator running, use the software shutdown (SYNTH:D8); (CMOS, active high).

Crystal Oscillator Feedback Capacitor Connection

Reference Clock Input for PLL. Drive with 1.2VP-P when using TCXO module.

GPS Clock Output to Baseband. This is the clock used by the ADC to sample the GPS data (CMOS).

Sampled IF Output, Bit 2 (CMOS). See Table 5.

Sampled IF Output, Bit 1 (CMOS). See Table 5.

Sampled IF Output, Bit 0 (CMOS). See Table 5.

IF Supply Connection. External RF bypass capacitor to ground required.

SPI Data Output (CMOS)

1st IF Input (Inverting). Connect this 2.5kΩ differentially terminated input to the 1st IF filter’s (-) output.

1st IF Input (Noninverting). Connect this 2.5kΩ differentially terminated input to the 1st IF filter’s (+)

output.

1st IF Output (Inverting). Connect this 2.4kΩ differential output to the 1st IF filter’s (-) input.

1st IF Output (Noninverting). Connect this 2.4kΩ differential output to the 1st IF filter’s (+) input.

RF Image-Reject Mixer Supply. External RF bypass capacitor to ground required.

RF Ground. Ultra-low inductance connection to ground. Place several vias to PC board ground plane.

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