Overview

The LC78631E is a compact disc D/A signal-processing LSI for CD-ROM drives that provides a variable clock error correction (VCEC) mode. The LC78631E demodulates the EFM signal from the optical pickup and performs de-interleaving, error detection, error correction, digital filtering, and other processing. The LC78631E includes an on-chip 1-bit D/A converter, and executes commands sent from a control microprocessor.

Features

• VCEC support

• Built-in PLL circuit for EFM detection (supports 4× playback)

• Built-in PLL for variable pitch playback (±13)

• 18KB RAM on chip

• Error detection and correction (corrects two errors in C1 and four errors in C2)

• Frame jitter margin: ±8 frames

• Frame synchronization signal detection, protection, and insertion

• Dual interpolation adopted in the interpolation circuit.

• EFM data demodulation

• Subcode demodulation

• Zero-cross muting adopted

• Servo command interface

• 2fs digital filter

• Digital de-emphasis

• Built-in independent left- and right-channel digital attenuators (239 attenuation steps)

• Supports the bilingual function

• Left/right swap function

• Built-in 1-bit D/A converter (third-order ∆∑ noise shaper, PWM output)

• Built-in digital output circuit

• CLV servo

• Arbitrary track jumping (of up to 255 tracks)

• Variable sled voltage (four levels)

• Six extended I/O ports and 2 extended output ports

• Built-in oscillator circuit using an external 16.9344 MHz or 33.8688 MHz (for 4× playback) element

• Supply voltage: 3.6 to 5.5 V (4.75 to 5.5 V for 4×playback mode)