LC78625E Schematic ( PDF Datasheet ) - Sanyo Semicon Device

Teilenummer LC78625E
Beschreibung Compact Disc Player DSP
Hersteller Sanyo Semicon Device
Logo Sanyo Semicon Device Logo 

Gesamt 30 Seiten
LC78625E Datasheet, Funktion
Ordering number : EN5502
Compact Disc Player DSP
The LC78625E is a CMOS LSI that implements the signal
processing and servo control required by compact disc
players, laser discs, CD-V, CD-I and related products. The
LC78625E 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.
This LSI is an improved version of the LC78620E. In
addition to supporting low-voltage operation, on/off
control of the de-emphasis function and use of the
bilingual function have been enabled in certain additional
• The LC78625E 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.
• A precise reference clock and the necessary internal
timings are generated using an external 16.9344 MHz
crystal oscillator.
• Disc 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
• Subcode Q signal output (LSB first) to a microprocessor
over the serial interface after performing a CRC error
• Demodulated EFM signal buffering in internal RAM to
handle up to ±4 frames of disc 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 LC78625E 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.
Package Dimensions
unit: mm
SANYO Electric Co.,Ltd. Semiconductor Bussiness Headquarters
TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110 JAPAN
22897HA (OT) No. 5502-1/35

LC78625E Datasheet, Funktion
Figure 4 General-Purpose Port Input Timing
Figure 5 General-Purpose Port Output Timing
No. 5502-6/35

6 Page

LC78625E pdf, datenblatt
• Command noise rejection
Command input noise reduction mode
Reset the above mode.
This command reduces the noise on the CQCK clock signal. While this is effective for noise pulses shorter than 500
ns, the CQCK timings tWL, tWH, and tSU (see page 5, figures 1 and 2), must be set to be at least 1 µs.
6. Focus servo circuit; Pin 16: FOCS, pin 17: FST, pin 18: FZD, pin 70: LASER
The FOCS, FST, and FZD pins are not required when the LC78625E is used in combination with an LA9230/40
Series LSI. FZD should be connected to 0 V when these pins are not used. The LA9230/40 Series focus start
command is identical to the LC78625E FOCUS START #1 command.
This command can be used to initialize the LC78625E by inputting FE (hexadecimal: Hexadecimal constants are
written with a dollar sign ($) prefix). Note that $00 is the reset command for the LA9230/40 Series, and should be
used with care since it clears the result of the automatic adjustment process and returns these chips to their initial
• Laser control
The LASER pin can be use as an extended output port.
• Focus start
When the LC78625E is used in combination with an LA9230/40 Series LSI, the focus start operation is executed
completely on the servo side by commands from the control microprocessor. The following section describes this
operation when the LC78625E is used in combination with an LA9210M or LA9211M.
When a focus start instruction (either FOCUS START #1 or FOCUS START #2) is input as a servo command, first the
charge on capacitor C1 is discharged by FST and the objective lens is lowered. Next, the capacitor is charged by FOCS,
and the lens is slowly raised. FZD falls when the lens reaches the focus point. When this signal is received, FOCS is
reset and the focus servo turns on. After sending the command, the microprocessor should check the in-focus detection
signal (the LA9210 DRF signal) to confirm focus before proceeding to the next part of the program. If focus is not
achieved by the time C1 is fully charged, the microprocessor should issue another focus command and iterate the focus
servo operation.
No. 5502-12/35

12 Page

SeitenGesamt 30 Seiten
PDF Download[ LC78625E Schematic.PDF ]

Link teilen

Besondere Datenblatt

LC78625Compact Disc Player DSPSanyo Semicon Device
Sanyo Semicon Device
LC78625ECompact Disc Player DSPSanyo Semicon Device
Sanyo Semicon Device


Hex D-Type Flip-Flop / Quad D-Type Flip-Flop.

Fairchild Semiconductor
Fairchild Semiconductor


KEC       |      2020       |      Kontakt     |      Suche