CLC5506

Gain Trim Amplifier (GTA)

General Description

The CLC5506 is a low-noise amplifier with programmable

gain for use in cellular base stations, WLL, radar and RF/IF

subsystems where gain-control is required to increase the

dynamic range. The CLC5506 allows designers to compen-

sate for manufacturing component tolerances and tempera-

ture variations in receiver front ends. Maximum amplifier

gain is set at 26dB . A three-line MICROWIRE serial inter-

face allows 16dB of attenuation from the max gain setting in

precise 0.25dB steps.

The CLC5506 uses a differential input and output, allowing

large output swings on a single 5V rail. The differential output

is well suited for impedance matching networks driving SAW

filters or directly driving differential input analog to digital

converters (ADC). The differential output also makes it pos-

sible to drive transformers allowing designers the ability to

match a wide variety of transmission lines. The output ampli-

fier has excellent output drive with low distortion.

Digital control of the CLC5506 is accomplished using MI-

CROWIRE Interface. Data Out and a Load Enable are incor-

porated so that more than one CLC5506/channel may be

programmed per system.

The CLC5506 maintains a 600MHz performance bandwidth

over its entire gain and attenuation range from +10dB to

+26dB. Gain control is divided into 64 equal steps of 0.25dB

and is dB-linear. Output drive and distortion performance are

excellent; In a 50

Ω system, the third-order output intercept

point is +22dBm at nominal gain of 18dB at 25˚C. The

CLC5506 operates over the industrial temperature range of

−40˚C to +85˚C.

Features

n 600MHz bandwidth

n 26dB maximum gain

n 16dB gain control range

n Attenuation step size:

0.25dB

n 4.8dB noise figure

n +22dBm output IP3

n Digital

″dB Linear″ gain control

n Supply voltage:

5V

n Supply current:

75mA

n Supply shutdown:

35µA

n Package: SOIC-14

n Typical at 25˚C

Applications

n Cellular base-stations

n Base station repeater

n Wireless Local Loop

n Radar

n Receivers

n IF amplifiers

n Digital IF receiver

n Software radio

n Satellite communications

Frequency Response vs. Gain Setting

DS101050-1

September 1999

© 1999 National Semiconductor Corporation

DS101050

www.national.com