General Description
The HT814D0 is a single chip LOG-PCM voice synthesizer LSI with 8.4-second voice capacity at a 6kHz sampling rate. The chip when triggered drives a speaker through an external transistor with a current switch D/A converter output. Negligible current will be consumed in the standby state.

Features
• Operating voltage: 2.4V~5.0V
• Directly drives an external transistor
• Low standby current (1μA typ. for VDD=3V)
• Minimal external components
• 508 words table ROM for key functions
• Programmable silence length and end-pulse width (minimal end-pulse width is 330s at a 6kHz sampling rate)
• 8.4-second voice capacity (based on a 6kHz sampling rate)
• 12 keys
• Controllable volume
• FLAG1 options
    - End-pulse output
    - 3HzB flash
    - 6HzB flash
    - Voice output indication
    - Busy output
• FLAG2 options
    - 3Hz flash
    - 6Hz flash
    - Busy output
• Key options
    - Stop key: KEY12
    - Random (only for KEY1)
    - Sequential (only for KEY1)
    - Repeat (for all KEYs)
    - Key debounce time (for all KEYs): 700μs, 22ms, 45ms, 180ms (based on a sampling rate of approximate 6kHz)
    - One shot (for all KEYs)
    - Level-trigger
    - Pull-high resistance (for all KEYs)
• Section options
    - Retriggerable
    - Non-retriggerable
• Dice form or 20/24-pin DIP/SOP package

Applications
• Leisure products
• Alarm clocks
• Public address system
• Alert and warning system
• Sound effect generators