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P
PRELIMINARY INFORMATION
data sheets provide specification for products not yet complete or characterized. They provide design target
information for customer planning purposes.
www.fairchildsemi.com
Features
Integrates almost all active components for conversion
Simple interface to SAW filter and digital demodulator
Gain control minimizes noise figure and distortion
Tuner control feature interfaces with variety of tuners
Demodulation of 64QAM constellations
40Msps ADC with >7.4 EFB @ 20Msps
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
9dB input noise figure at maximum gain
On-chip stable voltage reference
44-pin PLCC package
Applications
QAM receivers
Set-top receivers for digital cable
Internet surf-boards
Cable modems
ITV transceivers
Desktop video conferencing
IF sampling decoders
General Description
The RC6564 is a single chip solution for downconverting
and digitizing QAM signals so that they can be decoded in
the digital domain by custom DSP demodulators. The
RC6564 performs IF amplification with gain control, fre-
quency down conversion, frequency synthesis for mixer
Local Oscillator (LO) & system clock generation, and base-
band quantization with an Analog to Digital converter. The
input can directly interface to a SAW filter and maintain low
noise figure. 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 fig-
ure and signal distortion. The IF output is then down con-
verted and filtered using a double balanced mixer. This
output may be filtered even further, externally, before being
quantized by the on-chip A/D converter.The digital data out-
put can be processed to derive information for automatic
gain control (AGC) and automatic frequency control (AFC).
RC6564 is optimized to work with DSP decoders based on
IF sampling. The RC6564 also provides an optimum tuner
AGC control voltage useful for controlling the front-end
tuner gain.
For best performance Analog sections work on 12V & 5V
supplies. The digital sections work on a regulated 5V supply.
RC6564 is available in a single 44-pin PLCC package.
RC6564
IF-to-Digital Converter
Rev. 0.9.0