LC78681E Datasheet, PDF (1/23 Pages) Sanyo Semicon Device – Digital Signal Processor for Compact Disc Players

Ordering number : EN4521
CMOS LSI
LC78681E
Digital Signal Processor for
Compact Disc Players
Overview
The LC78681E is a CMOS LSI providing digital signal
processing (DSP) and servo control for compact disc
players and other audio devices, including laser disc
players and equipment using compact disc video
(CD-V) and compact disc interactive (CD-I) formats.
Functions include the demodulation of EFM (eight-to-
fourteen modulation) signals from optical pickups,
deinterleaving, detection and correction of error signals,
and signal processing for digital filters as well as other
features that can help reduce player cost. The LC78681E
also processes commands from the microprocessor for the
servo system. Direct interface is also possible with the
Sanyo LC7883K and LC78835, which are serial input
D/A converters with on-chip digital filters.
Functions
• HF signals that are input are sliced at an accurate level,
converted to EFM signals, and undergo phase-
comparison with VCO for PLL playback at an average
of 4.3218 MHz.
• Through external connection of a 16.9344 MHz crystal
oscillator, all required timing signals can be generated
on-chip, including the standard clock.
• Frame phase difference signals made from the playback
clock and the reference clock can control the speed of
the disc motor.
• Performs detection, protection, and interleaving of
frame synchronization signals, ensuring stable data
reading.
• Demodulates EFM signals and performs conversion to
8-bit symbol data.
• Separates subcodes from EFM demodulation signals for
output to an external microprocessor.
• After CRC checking, Q subcode signals are output to
the microprocessor by the serial I/O interface (LSB-first
output selectable).
• On-chip RAM performs buffering for EFM
demodulation signals, as well as absorbing up to ±4
frames of jitter due to fluctuations in the speed of disc
rotation.
• Performs unscrambling and deinterleaving for
rearranging the EFM demodulation signals into the
specified sequence.
• Performs detection and correction of error signals, as
well as error flag processing (double C1 and double C2
error correction system).
• Compares the results of the C1 flag and the C2 check to
set the C2 flag, and performs signal interpolation and
previous-value hold according to the C2 flag.
The interpolator uses 4-interpolation, where 0 volt down
is performed when the C2 flag is set four times in a row.
• Performs functions such as track jump, focus start, disc
motor start and stop, muting on and off, and track count
when the appropriate command is input from the
microprocessor (8-bit serial input).
• Features on-chip digital out.
• Can perform the desired track counting. High-speed
access is possible.
• Uses zero cross-muting.
• Fully supports double-speed dubbing.
• Supports all types of D/A conversion.
• Features on-chip digital level meter and peak meter
functions.
• Supports bilingual function.
Features
• Compact and space-saving 64-pin QFP package
• Silicon-gate CMOS design (low power dissipation)
• Single 5 V power supply (suitable for portable sets)
• DEMO pin for improved operability in adjustment
Any and all SANYO products described or contained herein do not have specifications that can handle
applications that require extremely high levels of reliability, such as life-support systems, aircraft’s
control systems, or other applications whose failure can be reasonably expected to result in serious
physical and/or material damage. Consult with your SANYO representative nearest you before using
any SANYO products described or contained herein in such applications.
SANYO assumes no responsibility for equipment failures that result from using products at values that
exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or other
parameters) listed in products specifications of any and all SANYO products described or contained
herein.
SANYO Electric Co.,Ltd. Semiconductor Bussiness Headquarters
TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110-8534 JAPAN
O3098HA (OT)/D2593JN B8-0235 No. 4521-1/23