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RF3857

DS110616

7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical

support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.

Pin

Function

Description

Interface Schematic

1GAIN SEL1

This pin selects high gain and bypass modes for Amplifier 1. Gain

Sel1<0.8V, Amp1 high gain. Gain Sel1>1.8V, Amp1 bypass.

2GND

Amplifier 1 ground connection. For best performance, keep traces physi-

cally short and connect immediately to ground plane.

3RFOUT1

Amplifier 1 output pin. This pin is an open-collector output. It must be

biased to VCC through a choke or matching inductor. This pin is matched to

50

 with the network shown in the evaluation board schematic.

4N/C

No internal connection.

5RFIN1

RF input pin for amplifier 1. This part is designed such that 50

 is the opti-

mal source impedance for best noise figure. Best noise figure is achieved

with only a series capacitor on the input.

6GND

Isolation ground connection. Can be grounded or not connected.

7GND

See pin 7.

8RFIN2

RF input pin for amplifier 2. See pin 5.

9N/C

No internal connection.

10

RFOUT2

Amplifier 2 output pin. See pin 3.

11

GND

Amplifier 2 ground connection. See pin 2.

12

GAIN SEL2

Selects high gain and bypass modes for Amplifier 2. See pin 1.

13

VREF2

Bias control for amplifier 2. An external resistor can be used to set the bias

14

N/C

No internal connection.

15

N/C

No internal connection.

16

VREF1

Bias control for amplifier 1. See pin 13.

RF IN

RF OUT

To Bias

Circuit

VBIAS