ARA2004
Reverse Amplifier with Step Attenuator
Data Sheet - Rev 2.1
FEATURES
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Low Cost Integrated Amplifier with Step
Attenuator
Attenuation Range: 0-58 dB, adjustable in 1 dB
increments via a 3 wire serial control
Meets DOCSIS distortion requirements at +60
dBmV output signal level
Low distortion and low noise
Frequency range: 5-100 MHz
5 Volt operation
-40 to +85
o
C temperature range
RoHS Compliant Package Option
MCNS/DOCSIS Compliant Cable Modems
CATV Interactive Set-Top Box
Telephony over Cable Systems
OpenCable Set-Top Box
Residential Gateway
performance at a +60 dBmV output level while only
requiring a single polarity +5 V supply. Both the input
and output are matched to 75 ohms with an
appropriate transformer. The precision attenuator
provides up to 58 dB of attenuation in 1 dB increments
via a three-wire serial interface. With external passive
components, this device meets IEC 1000-4-12 and
ANSI/IEEE C62.41-1991 100KHz ringwave tests, as
well as IEC1000-4-5 1.2/50
µS
surge tests. The
ARA2004 is offered in a 28-pin SSOP package
featuring a heat slug on the bottom of the package.
APPLICATIONS
S12 Package
28 Pin SSOP
with Heat Slug
PRODUCT DESCRIPTION
The ARA2004 is 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
device uses a balanced circuit design that exceeds
the MCNS/DOCSIS requirement for harmonic
Clock
Data
Enable
Balun
ARA2004
Low Pass
Filter
Upstream
QPSK/16QAM
Modulator
Clock
Data
RAM
ROM
5-42 MHz
Transmit Enable/Disable
MAC
Clock
Data
Microcontroller
with Ethernet
MAC
Diplexer
54-860 MHz
Double-
Conversion
Tuner
44 MHz
SAW
Filter
QAM Receiver
with FEC
10Base-T
Transceiver
RJ45
Connector
Figure 1: Cable Modem or Set Top Box Application Diagram
07/2005
ANADIGICS [ ANADIGICS, INC ]
