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www.fairchildsemi.com
Features
Integrated IF-to-Digital conversion
IF bandwidth from 30 to 80MHz
40MHz 8 bit ADC
Operating range between 8.5V to 13.2V
Demodulation of 64QAM constellations
Simple interface to SAW filter and digital demodulator
Tuner control feature interfaces with variety of tuners
Low phase noise LO generation
Crystal oscillator for fundamental or 3rd overtone mode
63dB peak conversion gain from IF to baseband
30dB minimum AGC range
45dB IMD3 end-to-end
On-chip 2V stable voltage reference
44-pin PLCC package
Applications
QAM receivers
Set-top receivers for digital cable
Internet surf-boards
Cable modems
Desktop video conferencing
IF sampling decoders
General Description
The RC6564A is a single chip solution for downconverting
and digitizing QAM signals that can be decoded in the digi-
tal domain by custom DSP demodulators. The RC6564A
performs IF amplification with gain control, frequency down
conversion, frequency synthesis for mixer Local Oscillator
(LO) and system clock generation, and baseband quantiza-
tion with an Analog to Digital converter. The input can
directly interface to a SAW filter and maintain low noise fig-
ure. Depending on the signal input level the gain may be
controlled over a 30dB range through an external analog
input signal. The gain reduction is done in two stages and
orchestrated in such a manner as to minimize noise figure
and signal distortion. The IF output is then down converted
and filtered using a double balanced mixer. This output can
be filtered even further, externally, before being quantized by
the on-chip A/D converter.The digital data output can be pro-
cessed to derive information for automatic gain control
(AGC) and automatic frequency control (AFC). RC6564A is
optimized to work with DSP decoders based on IF sampling.
The RC6564A also provides an optimum tuner AGC control
voltage useful for controlling the front-end tuner gain.
The IF and mixer section works at 9V. The oscillator works
on 5V supply. The A/D converter has one analog 5V supply
and two digital 5V supplies. The RC6564A is available in a
44 pin PLCC package.
RC6564A
IF-to-Digital Converter
Rev. 1.0.0