
92895HA (OT) No. 5130-1/34
Overview
The LC78620E is a CMOS LSI that implements the signal
processing and servo control required by compact disk
players, laser disks, CD-V, CD-I and related products. The
LC78620E provides several types of signal processing,
including demodulation of the optical pickup EFM signal,
de-interleaving, error detection and correction, and digital
filters that can help reduce the cost of CD player units. It
also processes a rich set of servo system commands sent
from the control microprocessor. It also incorporates an
EFM-PLL circuit and a one-bit D/A converter.
Functions
Input signal processing: The LC78620E takes an HF
signal as input, digitizes (slices) that signal at a precise
level, converts that signal to an EFM signal, and
generates a PLL clock with an average frequency of
4.3218 MHz by comparing the phases of that signal and
an internal VCO.
Precise reference clock and necessary internal timing
generation using an external 16.9344 MHz crystal
oscillator
Disk motor speed control using a frame phase difference
signal generated from the playback clock and the
reference clock
Frame synchronization signal detection, protection and
interpolation to assure stable data readout
EFM signal demodulation and conversion to 8-bit
symbol data
Subcode data separation from the EFM demodulated
signal and output of that data to an external
microprocessor
Subcode Q signal output to a microprocessor over the
serial I/O interface after performing a CRC error check
Demodulated EFM signal buffering in internal RAM to
handle up to ±4 frames of disk rotational jitter
Demodulated EFM signal reordering in the prescribed
order for data unscrambling and de-interleaving
Error detection, correction, and flag processing (error
correction scheme: dual C1 plus dual C2 correction)
The LC78620E sets the C2 flags based on the C1 flags
and a C2 check, and then performs signal interpolation
or muting depending on the C2 flags. The interpolation
circuit uses a quadruple interpolation scheme. The
output value converges to the muting level when four or
more consecutive C2 flags occur.
Support for command input from a control
microprocessor: commands include track jump, focus
start, disk motor start/stop, muting on/off and track
count (8 bit serial input)
Built-in digital output circuits.
Arbitrary track counting to support high-speed data
access
Zero cross muting
D/A converter outputs with data continuity improved by
8
×
oversampling digital filters. (These filters function as
4
×
oversampling filters during double-speed playback.)
Built-in third-order
∑
D/A converters (PWM output)
Built-in digital attenuator (8 bits – alpha, 239 steps)
Built-in digital de-emphasis
Built-in digital level and peak meter functions
Support for bilingual applications
Features
80-pin QIP (miniature, reduced space package)
Silicon gate CMOS process (for low power)
5 V single-voltage power supply (for use in portable
products)
Package Dimensions
unit: mm
3174-QFP80E
Preliminary
SANYO: QIP80E
[LC78620E]
Ordering number : EN
*
5130
CMOS LSI
LC78620E
Compact Disc Player DSP
SANYO Electric Co.,Ltd. Semiconductor Bussiness Headquarters
TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110-8534 JAPAN