OKI Develops Single-chip Audio LSI with 2W-Output Class-D Speaker Amplifier and DA Converter
Equipped with OKI’s proprietary technology to increase volume and improve sound quality for small speakers

ML26211
TOKYO, September 16, 2008 -- Oki Electric Industry Co., Ltd. (TSE: 6703) today announced it has developed the ML26211, a single-chip LSI for audio playback devices. The LSI includes a 2W-output filter-less Class-D speaker amplifier, 16-bit DA converter, and OKI's proprietary "LoudSound" technology to increase volume and improve sound quality for small speakers. Samples of the product will be shipped today and volume shipment is scheduled to start in February 2009.
"Integrating several audio features that conventionally were implemented in multiple devices into a single chip allowed OKI to reduce the packaging space by 50-80%, while ensuring a 1.5 times louder volume with "LoudSound," said Hiroshi Enomoto, President of Silicon Solutions Company at OKI. "The ML26211 is suitable for portable navigation devices (PND) that require loud volume. Going forward, we will continue to expand our sound LSI product line up that offers rich sound for small and light-weighted personal mobile applications."
Car navigation systems require functions such as a touch panel to operate the system, an LCD to display the route information, and voice guidance to guide the driver to the destination. However, it has been difficult to output clear and loud voice guidance when using PND as a car navigation system because of the loud noise in cars such as car audio and road noise, and because of the limitations of not being able to use the car speakers, and because it could not include a large built-in speaker due to its compact size. Thus, OKI developed the ML26211 to help solve and the issue of sound loudness when using small speakers and at the same time enabled fine acoustics even when devices become smaller.
Product characteristics
- Equipped with filter-less, 2W-output Class-D amplifier
A filter-less Class-D amplifier is included for rate output of 2W (4Ω speaker), 1.5W (8Ω speaker) using supply voltage of 5V. Advantages compared to conventional AB-class amplifiers include easier heatsink design and lower power consumption. It is also suitable for small battery-powered devices.
- Equipped with "LoudSound" technology for small speakers for improving sound quality
By applying OKI's proprietary acoustic adjusting technology, the volume output is 1.5 times louder than that of conventional products.
- Ultra small packaging by including all required functions for audio playback in a single chip
ML26211 includes filter-less Class-D amplifier, 16-bit DA converter, and sound-quality-adjusting technology "LoudSound" for small speakers, all in a single chip. With OKI's ultra small packaging technology, W-CSP (Wafer level Chip Size Package), the chips size is 2.5mm x 2.0mm, which is also offered in the size of 4mm x 4mm 24pin QFN.
[Reference] Sales plan
- Product name
- ML26211-00GD / ML26211-01HB / ML26211-02HB
- Sample shipment
- September 2008
- Evaluation board shipment
- September 2008
- Volume shipment
- ML26211-00GD: February 2009
ML26211-01HB: April 2009 (Planned)
ML26211-02HB: April 2009 (Planned)
[Reference] Product summary / characteristics
- Mono 16-bit DA converter (SN=95dB)
- Mono filter-less Class-D speaker amplifier
8Ω speaker (power voltage: 5V), rated output: 1.5W
4Ω speaker (power voltage: 5V), rated output: 2.0W - ALC/limiter
- Loud sound technology for small speakers "LoudSound"
- Serial audio interface
- Volume, mute function
- Sampling frequency: 8k, 11.025k, 12k, 16k, 22.05k, 24k, 32k, 44.1k, 48k Hz
- Clock frequency
11.2896MHz - 54MHz (When master is operating)
256fs/512fs/1024fs (When slave is operating) - CPU I/F
ML26211-00GD: 2-wired, 3-wired interface selectable
ML26211-01HB: 2-wired serial
ML26211-02HB: 3-wired serial - Driver voltage
Speaker amplifier: 2.7V - 5.5V
IO: 1.65V - 3.6V
Others (LVDD): 1.65V - 2.75V - Package
ML26211-00GD: 24-pin QFN (4mm x 4mm)
ML26211-01HB: 20-pin W-CSP (2.5 mm x 2.0mm)
ML26211-02HB: 20-pin W-CSP (2.5mm x 2.0mm)
About Oki Electric Industry Co., Ltd.
Founded in 1881, Oki Electric Industry Co., Ltd. is Japan's first telecommunications manufacturer, with its headquarters in Tokyo, Japan. OKI provides top-quality products, technologies and solutions to its customers through its info-telecom system business, semiconductor business and printer business. All three businesses function as a collective force to create exciting new products and technologies that satisfy a spectrum of customer needs in various markets. Visit OKI's global web site at http://www.oki.com/.
- ML26211-01HB and ML26211-02HB are currently under development.
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