ARA2005
Reverse Amplifier with Step Attenuator
FEATURES
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PRELIMINARY DATA SHEET - Rev 1.3
Low cost integrated monolithic GaAs amplifier
with step attenuator
Attenuation Range: 0-58 dB, adjustable in
4dB increments via a 4 wire parallel control
Meets DOCSIS distortion requirements at a
+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
S8 Package
28 Pin SSOP
PRODUCT DESCRIPTION
The ARA2005 is a monolithic GaAs device designed
to provide the reverse path amplification and output
level control functions in a Cable TV Set Top Box or
Cable Modem. It incorporates a digitally controlled
precision step attenuator, which is preceded by an
ultra low noise amplifier stage and followed by an
ulta-linear output driver amplifier. The ARA2005 uses
a balanced circuit design that exceeds the MCNS/
DOCSIS requirement for harmonic performance at a
+60 dBmV output level while requiring only a single
4
Attenuation Control
+5V supply. Both the input and output of the device
are matched to 75 Ohms with an appropriate
transformer. The precision attenuator provides up to
58 dB of attenuation in 4 dB increments,
programmable via a four-bit digital control 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 ARA2005 is offered in a 28-pin SSOP
package.
Balun
ARA2005
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
08/2001
ANADIGICS [ ANADIGICS, INC ]
