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OKI ADPCM Speech Synthesis LSI ML2280X Series
OVERVIEW
The ML2280X Series are speech synthesis LSIs that have P2ROM™ *1 for storing voice data. The voice output section has an ADPCM2 decoder achieving high speech quality, a D/A converter, and a low-pass filter. It is easy to configure a speech synthesizer by externally connecting a power amplifier and a CPU. The ML2280X Series allow selection of a playback method from among the 8-bit PCM, nonlinear 8-bit PCM, 16-bit PCM, and 4-bit ADPCM2 algorithms and enable volume control.
*1: P2ROM (Production Programmed ROM) is a trademark of Oki Electric Industry Co., Ltd.
Data Sheet
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ROM Capacity and Maximum Sound Generating Time
| Device Name | Built-in ROM | ROM Capacity | Max. Sound Generating Time (s) (when 4-bit ADPCM2 is used) |
||
|---|---|---|---|---|---|
| Sampling Frequency | |||||
| 4.0kHz | 8.0kHz | 16kHz | |||
| ML22808 | P2ROM | 8M bits | 524 | 262 | 131 |
| ML22804 (under development) |
4M bits | 262 | 131 | 65 | |
| ML22802 (under development) |
2M bits | 131 | 65 | 32 | |
Features and Main Specifications
- Uses P2ROM for reducing TAT (mask cost not required)
- Supports sampling frequencies from 4 kHz to 16 kHz
- Oki ADPCM2 compression technique that has abundant market history
- Equipped with a high-quality digital filter + 12-bit DAC
- Division up to 4 segments with a memory bank switching function (ML22808 and ML22804)
- Playback of up to 1,024 phrases (ML22808 and ML22804)
- Power supply voltage ranging from 2.7V to 3.6V
Block Diagram
Example of Application Circuit
