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|Single Chip Audio CODEC Features Integrated Capless Headphone
Tokyo, Japan - Asahi Kasei Microsystems Co., Ltd. (AKM) introduced the AK4665,
a 20-bit stereo A/D and D/A converter with built-in microphone and a capless headphone amplifier. This device is
ideal for mobile phone, smart-phones, music players and personal media players.
The AK4665 follows on from the
headphones-on-chip approach of the AK4569. A charge pump circuit has been added, which creates a negative power
supply for the headphone amplifier. This allows the audio signal to be zero volt biased, thus eliminating the need
for external DC blocking capacitors and therefore saving significant board space.
The AK4665 also
features a newly-developed mute circuit for fast 20 ms pop-free on/off switching. The analog power supply, 2.6V to
3.6V, achieves a wide dynamic range for good audio performance, while the digital power supply for external control
interfacing operates from 1.6V, giving the whole system a low power advantage.
digital recording automatic level control (ALC) provides a high-quality recording platform and also saves on power
consumption. The AK4665 has upgraded to stereo output and built-in volume functions are independent of headphone
output, to allow separate volume control of an external device such as a stereo speaker amplifier. Differences in
multi-source recording levels are adjusted by a sophisticated ALC circuit ensuring a constant playback volume.
Completing the AK4665’s function-rich offerings are delta-sigma architecture, an integrated PGA
microphone amplifier, integrated microphone power supply, playback digital volume and bass boost circuits, stereo
and mono external analog inputs, independent power on/off switching for each circuit block, and a three-wire uP
The AK4665 is available in a 32-pin QFN package. Evaluation boards and samples are
Miércoles, 19 Octubre, 2005 - 12:04