Home > Integrated Circuits > Speech Synthesis LSI > ML22Q321/ML22321 series

ML22Q321/ML22321 series

896Kbit Flash/Mask ROM built-in Speech Synthesis LSI with CPU interface / volume control function



package dimension figure


ML22Q321/ML22321 series is speech synthesis LSIs with built-in speaker amplifier.
It has internal Flash memory / MaskROM and can be controlled by event input from serial interface. The built-in speaker amplifier achieves a solution required for sound reproduction by one chip and high fidelity sound by the integrated 16bit DAC. 62 phrases are provided which are enough for small capacity series.
This series can easily play back sound by event input of 62 patterns from serial interface. Furthermore, the volume control function by external analog voltage input, and the speaker pin disconnection detection function and high temperature error detection function as fail safe functions are also installed.
As to Flash memory, users can write the sound data by themselves using LAPIS Semiconductor's specifically designed tools.

Playback time (second)

Part No. ROM size
Maximum playback time(s) (at Fsam=8.0kHz)
HQ-ADPCM 4bit ADPCM2 16bit PCM
ML22Q321 / ML22321 896K around 35 28 7


  • The control with 3 line serial interface is possible without changing microcontroller.
  • Melody and sound effects can be reproduced with high fidelity and high compression by HQ-ADPCM.
  • Speaker amp. is built in that enables sound playback by simply connecting a speaker.
  • Volume control is possible by external analog voltage input with standalone without CPU command.
  • High reliability with disconnection detection function and high temperature error detection function.
  • Two LSIs lineup with Mask/Flash pin compatibility.




  • Home security
    • Home fire alarms
    • Gas detection
    • Proximity sensors
  • Home electronics
    • Cookware
    • Bathing
  • Others
    • Operating sound of remote controller
    • Exercise machines
    • Interior goods
    • Toys, alarm clock
    • Mobile phone accessory
    • Sound effects in car, speech guidance


*1: Longest playback time when the sampling frequency is 6.4kHz in HQ-ADPCM.
Parameter Specification
Part No. ML22Q321 ML22321
ROM type Flash Mask
CPU interface Clock synchronous serial interface
ROM size (bit) 896K
Maximum playback time (sec) 43(*1)
Main features Speaker disconnection detection
Temperature protection circuit
Operating power supply voltage +2.3V to +5.5V
Operating frequency 4.096MHz
Operating temperature -40°C to +85°C
Speaker driver amplifier 1.0W (8Ω, at 5V)
D/A converter 16bit
Maximum number of events 62 events
Speech synthesis method 4bit ADPCM2, HQ-ADPCM, 8bit PCM,
16bit straight PCM
(Can be specified for each phrase)
Sampling frequency
when Fosc=4.096MHz
6.4k, 8.0k, 10.7k, 12.8k, 16.0k, 21.3k, 25.6k, 32.0k
(Can be specified for each phrase)
Package 30pin plastic SSOP

HQ-ADPCM is a high sound quality audio compression technology of "Ky's".
"Ky's" is a registered trademark of National University Corporate Kyushu Institute of Technology.




() is ML22331

Application Circuit