audio/videoZONE Products for the week of June 10, 2002
AKM Says . . .
AK4534: Low-power Codec Integrates PLL, Audio Amplifiers,
Mixing and Microphone Circuits
Single-chip analog integration bridges audio gap between cell
phones and PDAs
Asahi Kasei Microsystems Semiconductor, Inc. (AKM), a leading supplier of
audio ICs for professional and consumer markets introduced the AK4534, a
single-chip codec that combines key features for portable applications.
Among the integrated capabilities are low-power consumption, a 16-bit monaural
analog-to-digital converter (ADC), a stereo digital-to-analog converter
(DAC), a PLL, headphone and speaker amplifiers. The AK4534 is targeted at
portable, PDA and cellular phone applications.
The AK4534's DAC and ADC support 16-bit sampling rates from 8 kHz to 48 kHz. The variable sample rates increase memory efficiency. The built-in mono ADC, Automatic Level Control (ALC) and microphone amplifiers ensure trouble-free recording for voice recognition and audio memo applications.
For audio playback, a stereo DAC and digital attenuator are used in conjunction with the built-in headphone and speaker amplifiers. The headphone amplifier delivers up to 15 milliwatts of power at 8-32 ohm loads, while the mono speaker amplifier delivers up to 150 milliwatts of power. This integration of DAC and amplifiers reduces board space and component count.
The AK4534 has dual mono and stereo analog inputs for mixing a variety
of external analog signals from cell phone controllers, MP3 decoders and
external sources. This analog mixing allows designers to create a unified
audio system for combo cell phone/PDA devices. In addition, the AK4534 has
a built-in PLL for internal audio clock generation, thereby simplifying
synchronization of system microprocessor and audio clocks.
analogZone Says . . .
This part was released a little while ago but I chose not to review it at that time because I couldn't place the market properly in my mind. After having seen copy-cat devices and actual OEM products since I am now able to better understand where these parts will be going in the combined cell phone/PDA arena. The provision of analog inputs, microphone input with automatic level control, stereo audio channels and both headphone and speaker amplifiers make this a very powerful single-chip solution for those integrated devices, where size, power consumption and heat will be even more significant. Obviously, however, the street price for large volumes will bear no relationship to the established 1000-piece pricing.
I particularly like the notion of putting the gain control system for the audio outputs on the digital side, with a digital potentiometer. The power levels, too, are very adequate for the tasks.
A data sheet could not be found on the company's web site and a request for a copy was not responded to. However, we know that this is a nominal 3.0 V part and that each section of the codec can be powered down independently -- a very attractive feature for portable products.
AKMs selling chain in the U.S. is not particularly strong but the market is currently very much in Asia anyway, and this part will do exceptionally well.
The AK4534 is sampling in LQFP-48 and QFN-52 and is priced at $8.21 in
1000-piece lots.