Overview
The SM5859 is a compression and non compression type anti-shock memory controller LSI for compact disc players. The compression level can be set in 4 levels, and external memory can be selected from 4 options (1M, 1M×2, 4M, 4M×2). Digital attenuator, soft mute and related functions are also incorporated. It operates from a 2.7 to 5.5 V wide supply voltage range.

Features
- 2-channel processing
- Serial data input
    •2s complement, 16-bit/MSB first, rear-packed format
- System clock input
    •384fs (16.9344 MHz)
- Anti-shock memory controller
- ADPCM compression method
    •4-level compression mode selectable
        4-bit compression mode 2.78 s/Mbit
        5-bit compression mode 2.22 s/Mbit
        6-bit compression mode 1.85 s/Mbit
        Full-bit non compression mode 0.74 s/Mbit
    •4 external DRAM configurations selectable
        2×4M DRAM (1M×4 bits)
        1×4M DRAM (1M×4 bits)
        2×1M DRAM (256K×4 bits)
        1×1M DRAM (256K×4 bits)
- Compression mode selectable
- Microcontroller interface
    •Serial command write and state read-out
    •Data residual quantity detector:
        15-bit operation, 16-bit output
    •Digital attenuator Full-bit setting
    •Soft attenuator function Noiseless attenuation-level switching (256- step switching in 23 ms max.)
    •Soft mute function
        Mute ON in 23 ms max. Direct return after soft mute release
    •Forced mute
- Extension I/O
    Microcontroller interface for external control using 5 extension I/O pins
- +2.7 to +5.5 V wide operating voltage range
- Schmitt inputs
    All input pins (including I/O pins) except CLK (system clock)
- Reset signal noise elimination
    Approximately 3.8 µs or longer (65 system clock pulses) continuous LOW-level reset
- 44-pin QFP package (0.8 mm pin pitch)