Reverse Amplifier with Step Attenuator
features
•
Low Cost Integrated Monolothic GaAs Amplifier
With Step Attenuator
•
Attenuation Range: 0-30 dB, Adjustable In
2dB Increments Via a 4 Wire Parallel Control
•
Meets DOCSIS Distortion Requirements at
+58dBmV Output Signal Level
•
Low Distortion and Low Noise
•
Low Signal toNoise Ratio at All Gain Levels
•
Frequency Range: 5-100 MHz
•
5 Volt Operation
•
RoHS-Compliant Package Option
ara05050
Data Sheet - Rev 2.7
applications
•
MCNS/DOCSIS Compliant Cable Modems
•
CATV Interactive Set-Top Box
•
OpenCable Set-Top Box
•
•
Fiber Nodes
Cable Modem Termination Systems (CMTS)
s12 package
28 pin ssop with Heat slug
product description
The ARA05050 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 device is capable of meeting
the MCNS/DOCSIS requirements for harmonic
4
Attenuation Control
performance at a +58dBmV output level while requiring
only a single polarity +5V supply. Both the input
and the output are single-ended and matched to 75
Ohms. The precision attenuator provides up to 30 dB
of attenuation in 2 dB increments. The ARA05050 is
offered in a 28-pin SSOP package that features a heat
slug on the bottom of the package, and is available in
a RoHS-compliant option.
Switch
ARA05050
LPF
Balun
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
04/2012