ARA2008
Reverse Amplifier with Step Attenuator
ADVANCED PRODUCT INFORMATION - Rev 0.0
FEATURES
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Low cost integrated amplifier with step
attenuator
Attenuation Range: 0-58 dB, adjustable in
1dB increments via a 3 wire serial control
Meets DOCSIS distortion requirements at
+60dBmV output signal level
Low distortion and low noise
Frequency range: 5-100MHz
5 Volt operation
-40 to +85
0
C temperature range
MCNS/DOCSIS Compliant Cable Modems
CATV Interactive Set-Top Box
Telephony over Cable Systems
OpenCable Set-Top Box
Residential Gateway
APPLICATIONS
20 Pin SSOP Package
PRODUCT DESCRIPTION
The ARA2008 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
performance at a +60dBmV output level while only
Clock
Data
Enable
requiring a single polarity +5V 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 1.2/50mS surge tests. The
ARA2008 is offered in a 20-pin SSOP package.
Balun
ARA2008
Low Pass
Filter
Upstream
QPSK/16QAM
Modulator
Clock
Data
RAM
ROM
5-42 MHz
Transmit Enable/Disable
MAC
Clock
44 MHz
Data
Microcontroller
with Ethernet
MAC
Diplexer
54-860 MHz
Double-
Conversion
Tuner
SAW
Filter
QAM Receiver
with FEC
10Base-T
Transceiver
RJ45
Connector
Figure 1. Cable Modem or Set Top Box Application Diagram
10/2001
ANADIGICS [ ANADIGICS, INC ]
