Low-power 32-bit Stereo CODEC with Microphone/Headphone/Speaker amplifiers


Tokyo Japan, Aug 7 2013, Asahi Kasei Microdevices Corporation (AKM) today launched the AK4954A, the newest product in the AKM Audio 2 GoTM family, an enhanced version of the AK4953A that is widely used for sound processing in portable multimedia players and IC recorders. This 32-bit stereo CODEC supports a sampling frequency up to 96kHz. Microphone, headphone and speaker amplifiers are integrated, making the AK4954A ideal for IC recorders and portable multimedia players.


The AK4954A features an outstanding performance to power consumption ratio. The stereo ADC and DAC (in headphone (HP) out mode) achieve 100dB dynamic range: the best performance ever in the Audio 2 GoTM brand family at a very low power consumption of 10.4mW for the ADC and 6.2mW for the DAC (in HP out mode). Newly designed short delay decimation filters are implemented in addition to traditional digital filters, enabling a choice of differing sound quality. The AK4954A has an integrated charge pump that generates an internal negative rail, enabling ground-referenced outputs for the cap-less headphone amplifier. This headphone amplifier eliminates large AC-coupling capacitors, achieving stable signal characteristics in low frequency bands, reducing cost and meeting space saving requirements for portable devices. The integrated speaker amplifier has a wide operating voltage range of 0.9V to 5.5V, enabling a direct connection to a single cell battery. 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 is realized using an internal five-band equalizer.


The AK4954A integrates a low noise stereo microphone preamplifier that supports single-ended inputs, a power supply circuit for an external microphone supporting two line output switching, an ALC circuit for both recording and playback, a digital volume control, a 3-band dynamic range control circuit for playback, a 20mW stereo headphone amplifier and a 400mW mono speaker amplifier. 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 AK4954A supports sampling rates from 8kHz to 96kHz, and the operating voltage ranges from 2.5V to 3.5V for the analog block, from 1.6V to 1.98V for the digital block, from 0.9V to 5.5V for the speaker amplifier and from 1.6V to 3.5V for the digital interface block. It is housed in a space saving small 32-pin QFN package (4.0mm x 4.0mm).  

Evaluation boards and samples are available now.  

To obtain more information abput the AK4954A, please visit here.




About “Audio 2 Go (TM)

Audio 2 Go(TM) products are designed for portable audio applications, including mobile phones and media players, which provide feature-rich, single chip solution with low power consumption and high audio fidelity.


[Note] AKM and Audio 2 Go are trademarks of Asahi Kasei Microdevices Corporation.