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Power
Management for
Mobiles (PM)
AT73C213
Audio Interface
for Portable
Handsets
1. Description
The AT73C213 is a fully integrated, low-cost, combined stereo audio DAC and audio
power amplifier circuit targeted for Li-Ion or Ni-Mh battery powered devices such as
mobile phones, smartphones, PDA, DECT phones, digital still cameras, music players
or any other type of handheld device where an audio interface is needed.
The stereo DAC section is a complete high performance, stereo audio digital-to-ana-
log converter delivering a 93 dB dynamic range. It comprises a multibit sigma-delta
modulator with dither, continuous time analog filters and analog output drive circuitry.
This architecture provides a high insensitivity to clock jitter. The digital interpolation fil-
ter increases the sample rate by a factor of 8 using 3 linear phase half-band filters
cascaded, followed by a first order SINC interpolator with a factor of 8. This filter elim-
inates the images of baseband audio, retaining only the image at 64x the input sample
rate, which is eliminated by the analog post filter. Optionally, a dither signal can be
added that reduces possible noise tones at the output. However, the use of a multibit
sigma-delta modulator already provides extremely low noise tone energy.
Master clock is from 256 or 384 times the input data rate, allowing choice of input data
rate up to 50 kHz, including standard audio rates of 48, 44.1, 32, 16 and 8 kHz.
The DAC section is followed by a volume and mute control and can be simultaneously
played back directly through a stereo 32 Ohm headset pair of drivers.
2744A鈥揚(yáng)MGMT鈥?7-Jan-05