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)