Home > Integrated Circuits > Speech Synthesis LSI > ML22Q573/ML2257x series

ML22Q573/ML2257x series

4-Channel Mixing Speech Synthesis LSI with Built-in Flash/Mask ROM for Automotive



package dimension figure


The ML22Q573/ML2257x series is a high-quality speech synthesis LSI with built-in Mask ROM/Flash memory suitable for automotive applications. The LSI, which includes a high-quality (HQ-ADPCM) decoder, a 16-bit DAC, a low-pass filter, and a monaural speaker amplifier, incorporates the peripheral components necessary for speech and sound output in a single chip. The LSI contains a variety of functions including 4-channel simultaneous playback, volume control and edit ROM function for efficient memory usage.

Playback Time

(HQ-ADPCM method)
Part number Memory Type ROM Capacity
Maximum Playback Time(s)
fs=8.0k fs=16.0k fs=32.0k
ML22Q573 Flash 4M 161 80 40
ML22573 Mask
ML22572 2M 79 39 19


  • Built-in high-quality decoder (HQ-ADPCM)
  • Built-in speaker amplifier (1.0W/5V using 8Ω speaker)
  • Built-in external analog mixing function
  • Power-supply-voltage detection
  • Development is supported with an evaluation board and an exclusive programmer for ML22Q573
  • 4-channel mixing function enabling simultaneous playback
  • CPU I/F: Clock synchronous serial interface


Applicatin Example


Parameter Specification
Part number ML22Q573/ML2257x series
Speech synthesis method HQ-ADPCM
8-bit nonlinear PCM
8-bit PCM, 16-bit PCM
(Can be specified for each phrase)
Sampling frequency
6.4k, 8.0k, 12.0k, 12.8k, 16.0k, 24.0k, 25.6k, 32.0k, 48.0kHz
(Can be specified for each phrase)
Speaker amplifier output 1.0W (8Ω, 5V)
Number of playback phrases Max. 1,024 phrases
Other functions Volume control function, Repeat function
Operating power supply voltage +2.7V to +5.5V
Operating temperature -40°C to +105°C
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.

Block Diagram


ML22Q573 Block Diagram


ML2257x series Block Diagram

Application Circuit Examples

At using internal speaker amplifier (speaker output)

Application Circuit Example

At using external speaker amplifier (line output)

Application Circuit Example