RF2494 datasheet(4/14 Pages) RFMD

4 / 14 page

Preliminary

8-56

RF2494

Rev A0 010730

Function

Description

Interface Schematic

LNA OUT

RF signal output for external 50

Ω filtering.The use of a filter here is

optional but does provide for lower noise floor and better out-of-band

rejection.

See pin 14.

VCC4

Supply voltage for the LNA. This pin should be bypassed with a 10 pF

capacitor to ground as close to the pin as possible. The shunt induc-

tance from this pin to ground via the supply decoupling must be tuned

to match the LNA output to 50

Ω at the desired operating frequency.

LNA gain control. When GAIN SEL is > VCC- 300mV, LNA gain is at 10

dB. When GAIN SEL is <300mV, the LNA gain is -6dB.

See pin 14.

LNA IN

This pin is NOT internally DC blocked. An external blocking capacitor

must be provided if the pin is connected to a device with DC present. If

a blocking capacitor is required, a value of 2pF is recommended.

See pin 14.

LNA IN

BIAS

VCC4

GAIN SEL

P15

LNA OUT

EXTERNAL

DECOUPLING

Microstrip

-16 dB

RF2494 Datasheet(PDF) 4 Page - RF Micro Devices