RF2917 データシートの表示（PDF） - RF Micro Devices

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RF2917

433/868/915MHZ FM/FSK RECEIVER

RF Micro Devices 

RF2917

11

Pin

1

2

3

4

5

6

7

8

9

Function

VCC1

RX IN

Description

This pin is used to supply DC bias to the receiver RF electronics. A RF

bypass capacitor should be connected directly to this pin and returned

to ground. A 22pF capacitor is recommended for 915MHz applications.

A 100pF capacitor is recommended for 433MHz applications.

RF input pin for the receiver electronics. RX IN input impedance is a

low impedance when enabled. RX IN is a high impedance when the

receiver is disabled.

Interface Schematic

RX IN

GND1

LNA OUT

GND2

MIX IN

Ground connection for RF receiver functions. Keep traces physically

short and connect immediately to ground plane for best performance.

Output pin for the receiver RF low noise amplifier. This pin is an open

collector output and requires an external pull up coil to provide bias and

tune the LNA output. A capacitor in series with this output can be used

to match the LNA to 50Ω impedance image filters.

GND2 is connection for the 40 dB IF limiting amplifier. Keep traces

physically short and connect immediately to ground plane for best per-

formance.

RF input to the RF Mixer. An LC matching network between LNA OUT

and MIX IN can be used to connect the LNA output to the RF mixer

input in applications where an image filter is not needed or desired.

LNA OUT

MIX IN

GND3

MIX OUT

IF1 IN-

GND3 is the ground connection for the receiver RF mixer.

IF output from the RF mixer. Interfaces directly to 10.7MHz ceramic IF

filters as shown in the application schematic. A pull-up inductor and

series matching capacitor should be used to present a 330Ω termina-

tion impedance to the ceramic filter. Alternately, an IF tank can be used

to tailor the IF frequency and bandwidth to meet the needs of a given

application. In addition to the matching components, a 15pF capacitor

should be placed from this pin to ground.

Balanced IF input to the 40dB limiting amplifier strip. A 10nF DC block-

ing capacitor is required on this input.

MIX OUT+

IF1 BP+

60 kΩ

330

IF1 IN+

VCC

IF1 BP-

60 kΩ

330

IF1 IN-

10

IF1 IN+ Functionally the same as pin 9 except non-inverting node amplifier

See pin 9.

input. In single-ended applications, this input should be bypassed

directly to ground through a 10 nF capacitor.

11

IF1 BP+ DC feedback node for the 40dB limiting amplifier strip. A 100nF bypass See pin 9.

capacitor from this pin to ground is required.

12

IF2 BP- See pin 11.

See pin 9.

13

IF1 OUT IF output from the 40dB limiting amplifier. The IF1 OUT output presents

a nominal 330Ω output resistance and interfaces directly to 10.7MHz

ceramic filters.

IF1 OUT

14

VREF IF DC voltage reference for the IF limiting amplifiers (typically 1.1V). A

0.1µF capacitor from this pin to ground is required.

15

GND5

Ground connection for 60dB IF limiting amplifier. Keep traces physically

short and connect immediately to ground plane for best performance.

11-132

Rev B2 010118

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