Overview
The SM5901 is a compression and non compression type anti-shock memory controller with built-in 1M DRAM LSI for compact disc players. The compression level can be set in 4 levels, and external 1M DRAM can be connected to expand the memory to 2M bits. Digital attenuator, soft mute and related functions are also incorporated. It operates from a 2.7 to 3.3 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 0.70 s/Mbit
    • External memory can be connected
        2×1M DRAM (256K×4 bits)
            Internal and external 1M DRAMs
        1×1M DRAM (256K×4 bits)
            Only internal 1M DRAM
- 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 +3.3 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)