Overview

The LC78684E integrates, on a single chip, CD-ROM signal-processing functions, MP3 signal-processing functions, and CD-DA shockproof signal-processing functions. The LC78684E achieves significant power savings by implementing signal-processing functions using hardwired structures.

A CD player that supports playback of MPEG audio (MP3) recorded on CD media as well as CD-DA shockproof playback can be implemented by combining this IC with a CD DSP, DRAM, and audio D/A converter, and other circuits.

Features

• MP3 Decoding Functions (MPEG audio standard [ISO/IEC 11172-3] layer 3)

- Decodes to a digital audio signal MP3 data decoded by the CD-ROM decoder and outputs that audio signal.

- Supports all bit rates, including variable bit rate operation.

- Supports the following sampling rates.

MPEG1 (Fs = 32 K, 44.1 K, 48 K)

MPEG2 (Fs = 16 K, 22.05 K, 24 K)

MPEG2.5 (Fs = 8 K, 11.025 K, 12 K)

- Can read out the MPEG header and ancillary data.

- Automatically mutes the signal on CRC errors using an MP3 CRC check function.

- External MPEG serial data input function supports memory card playback.

• CD-ROM Decoding Functions

- Supports CD-ROM modes 1 and 2 (forms 1 and 2)

- Faithfully reproduces data stored on CD-ROM discs using CD-ROM error correction functions.

- Header and sector management

- Supports playback speeds up to 4×.

- In addition to data buffering also supports C2 error flag buffering.

- Provides external serial output of decoded CD-ROM data.

• CD-DA Playback Functions (Shockproof support)

- Shockproof operation for about 180 seconds (compressed mode) when 64M DRAM is used.

- Shockproof function supports compressed, uncompressed, and data through modes.

- VCEC (variable speed) supports up to 4×-speed playback.

• Audio Signal Processing

- Serial audio signal output using LRCK, BCK, and DATA signals. (I²S format, either 16-bit or 20-bit precision PCM output, data-slot supports 16-bit, 24-bit, and 32-bit modes)

- Digital bass boost function (4 modes), attenuator function, and muting (-f, -12 dB)

- Provides a base clock (384 fs) output pin for use with external digital filters and D/A converters.

• DRAM Interface

- Supports the use of from 1M to 64M of external DRAM (EDO, 2CAS, 16-bit data bus memory)

- Supports allocation of a user area in DRAM during CD-ROM (MP3) playback.

• Package and Power Supply Voltage Specifications

- Package: Sanyo QFP80 (14 × 14) (unit: mm)

- Supply voltage

Internal power supply: 1.8 V (typical)

I/O power supply: 3.3 V (typical)

Analog system power supply: 3.3 V (typical)