Tokyo Japan, Dec 22 2011, Asahi Kasei Microdevices Corporation today launched the AK4955, the newest product in the AKM Audio2goTM family. The AK4955 is an enhanced version of the AK4646, which is widely used for sound processing in digital still and video cameras. The 24-bit stereo CODEC integrates microphone, speaker and cap-less video amplifiers in addition to an LDO, saving significant board space compared to existing solutions that require two or three chips. A DSP for sound processing is also integrated, featuring motor noise cancellation and an automatic wind noise filter for recording, and a three-band dynamic range control function for playback. The AK4955 an ideal solution for digital still and video cameras.

Designed for low power, the AK4955 features an outstanding performance to power consumption ratio. The stereo ADC achieves 96dB dynamic range and 82dB S/(N+D), and the stereo DAC (lineout) achieves 92dB dynamic range and 85dB S/(N+D) at a very low supply current. The AK4955 has an integrated charge pump that generates an internal negative rail, enabling 0V pedestal level outputs for the cap-less video amplifier. This video amplifier eliminates large AC-coupling capacitors, reducing cost and meeting space saving demands for portable devices. The speaker pressure levels can be greatly increased with a three-band dynamic range control function. The microphone input circuit includes a digital microphone interface, converting 1-bit data (PDM) into 24-bit linear PCM data. The ADC output and digital microphone output are automatically adjusted by an ALC circuit, and high quality sound recording can be realized using the internal five-band equalizer.

The AK4955 integrates a low noise stereo microphone preamplifier that supports single-ended inputs, a power supply circuit for two sets of stereo microphones, an ALC circuit for recording and playback, a digital volume control, a cap-less video amplifier supporting 0V pedestal level outputs, a mono speaker amplifier with a maximum output of 600mW, and a stereo line out amplifier with +2dB output. An integrated PLL can generate all required audio clocks internally, ensuring a simple interface to external processors. The PLL includes an internal loop filter, eliminating the traditional external connection requirement. Functions are controlled through serial control, either 3-wire or I²C bus interfaces. The AK4955 supports sampling rates from 7.35kHz to 48kHz, and the operating voltage ranges from 2.7V to 3.6V for the analog block, from 1.6V to 2.0V for the digital block, from 2.7V to 5.5V for the lineout block, from 2.7V to 5.5V for the speaker amplifier and from 1.6V to 3.6V for the digital interface block. It is housed in a space saving small 36-pin CSP package (3.0mm 3.0mm). Evaluation boards and samples are available now. To obtain more information, contact Asahi Kasei Microdevices Corporation, Data Converters, 1-105 Kanda Jinbocho, Chiyoda-ku, Tokyo 101-8101, Japan or visit our web site “www.akm.com”.

The Audio2go™ The Audio2goTM brand identifies AKM products that are designed for portable applications, including mobile phones, media players, digital camera and PDAs. The Audio2go™ brand product family provides a feature rich, single chip solution offering low power consumption and high Audio fidelity.

AK4955 Product Infomation