ARA2000 Datasheet, PDF (1/20 Pages) ANADIGICS, Inc – Address-Programmable Reverse Amplifier with Step Attenuator

FEATURES
• 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 ^oC temperature range
APPLICATIONS
• MCNS/DOCSIS Compliant Cable Modems
• CATV Interactive Set-Top Box
• Telephony over Cable Systems
• OpenCable Set-Top Box
• Residential Gateway
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
ARA2000
Address-Programmable Reverse
Amplifier with Step Attenuator
Data Sheet - Rev 2.2
S12 Package
28 Pin SSOP
with Heat Slug
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.
Balun
ARA2000
Low Pass
Filter
Upstream
QPSK/16QAM
Modulator
5-42 MHz
Transmit Enable/Disable
2
Address Control
Clock
Data
MAC
Diplexer
54-860 MHz
Double-
Conversion
Tuner
44 MHz
SAW
Filter
Clock
Data
QAM Receiver
with FEC
RAM ROM
Microcontroller
with Ethernet
MAC
10Base-T
Transceiver
RJ45
Connector
Figure 1: Cable Modem or Set Top Box Application Diagram
06/2004