S23

28 PIN SSOP PACKAGE

FEATURES

APPLICATIONS

ARA2001S23

CATV Reverse Amplifier with Step Attenuator

·

Low cost integrated monolithic GaAs

amplifier with step attenuator.

·

Attenuation Range: 0 – 58 dB, variable in

1 dB steps via 8 bit serial input.

·

Meets DOCSIS distortion requirements at

+60 dBmV

·

Low distortion & Low noise figure

·

Frequency range: 5 – 100 MHz

·

5 Volt operation

·

MCNS/DOCSIS Compliant Cable Modems

·

CATV Interactive Set-Top Box

·

Telephony over Cable Systems

Description

The ARA2001S23 is a GaAs IC designed to provide the reverse path amplification and output level control

functions in a CATV Set-Top Box or Cable Modem. It incorporates a digitally controlled precision step

attenuator that is preceded by an ultra low noise amplifier stage, and followed by an ultra-linear output driver

amplifier. This part is a balanced design that meets or exceeds the MCNS/DOCSIS requirement for

harmonic performance @ +60dBmV output levels while only requiring a single polarity +5V supply. Both the

input and output are matched to 75 ohms. The precision attenuator provides up to 58 dB of attenuation in 1

dB increments. The ARA2001S23 is supplied in a 28-pin SSOP package featuring a thermal heat slug on the

bottom of the package. Soldering this heat slug to the ground plane of the PC board ensures the lowest

possible thermal resistance for the device resulting in a long MTF.

·

Open Cable Set-Top Box

PA

MAC

QAM

Receiver

w/FEC

SAW

Double

Conversion

Tuner

Microcontroller

w/Enet MAC

RAM

ROM

10Base-T

Tranceiver

Balun

ARA2001 Reverse Amp

54-860 MHz

Gain Control

Clock

Clock

Data

Data

RJ45

Connector

45 MHz IF

Tx Enable/Disable

CMOS IC

PA

PA

"Shutdown"

~

Low Pass

Filter

Diplexer

Filter

Coax Input

ATTN

1/2/4/8/16/32 dB

PA

~

"Shutdown"

Low Pass

Filter

Upstream

QPSK/

16-QAM

Modulator

Figure 1: Cable Modem or Interactive Set-Top Box Block Diagram