ARA2000
Address-Programmable Reverse
Amplifier with Step Attenuator
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 a
+60dBmV output signal level
Programmable address allows multiple parts
to share control bus
Low distortion and low noise
Frequency range: 5-100MHz
5 Volt operation
-40 to +85
o
C temperature range
MCNS/DOCSIS Compliant Cable Modems
CATV Interactive Set-Top Box
Telephony over Cable Systems
OpenCable Set-Top Box
Residential Gateway
circuit design that exceeds the MCNS/DOCSIS
requirement for harmonic performance at a
+60dBmV output level while only 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. The
ARA2000 has a programmable address that allows
multiple devices to share a common control bus.
The ARA2000 is offered in a 28-pin SSOP package
featuring a heat slug on the bottom of the package.
Data Sheet - Rev 2.2
APPLICATIONS
S12 Package
28 Pin SSOP
with Heat Slug
PRODUCT DESCRIPTION
The ARA2000 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
Clock
Data
Enable
Balun
ARA2000
Low Pass
Filter
Transmit Enable/Disable
Upstream
QPSK/16QAM
Modulator
Clock
Data
RAM
ROM
5-42 MHz
2
Address Control
MAC
Clock
Data
Microcontroller
with Ethernet
MAC
44 MHz
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
06/2004
ANADIGICS [ ANADIGICS, INC ]
