General Description
The HT819D0 is a single chip LOG-PCM voice synthesizer LSI with 4.2-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.
The HT819D0 provides 6 key inputs and 2 programmable FLAG outputs. With a 2.4V~5.0V power supply, a complete synthesized voice playback system can be easily built with very few external components.
The customer’s voice sources are recorded section by section into an internal mask ROM. The sectional playback arrangement instructions of each key are stored in the table ROM. The key features are also programmable. With such a flexible structure, the HT819D0 is excellent for versatile voice applications.

Features
• Operating voltage: 2.4V~5.0V
• Directly drives an external transistor
• Low standby current (1µA typ. for VDD=3V)
• Minimal external components
• 252 words table ROM for key functions
• Programmable silence length and end-pulse width (minimal end-pulse width is 330µs at a 6kHz sampling rate)
• 4.2-second voice capacity
• Section options:
   – Retriggerable
   – Non-retriggerable
• FLAG1 options:
   – End-pulse output
   – 3HzB flash
   – 6HzB flash
   – Voice output indication
   – Busy output
• FLAG2 options:
   – 3Hz flash
   – 6Hz flash
   – Busy output
• Controllable volume
• 6 keys
• Key options:
   – Stop key: KEY6
   – 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 6kHz sam pling rate of)
   – One shot (for all KEYs)
   – Pull-high resistance (for all KEYs)
• Dice form or 16-pin DIP/SOP

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