AT73C240 Datasheet, PDF (1/38 Pages) ATMEL Corporation – Power Management and Analog Companions

Features
• Stereo Audio DAC
– 2.7V to 3.3V Analog Supply Operation
– 2.4V to 3.3V Digital Supply Operation
– 20-bit Stereo Audio DAC
– 90 dB SNR Playback Stereo Channels
– 32 Ohm/20 mW Stereo Headset Drivers with Master Volume and Mute Controls
– Stereo Line Level Input with Volume Control/Mute and Playback through the
Headset Drivers
– Accepts Mixed Signals from All Signal Paths (Line Inputs and DAC Output)
– 8, 11.024, 16, 22.05, 24, 32, 44.1 and 48 kHz Sampling Rates
– 256x or 384xFs Master Clock Frequency
– I2S Serial Audio Interface
• Mono Audio Power Amplifier
– Supply Input from Main Li-Ion Battery (3V to 5.5V)
– 440 mW on 8 Ohm Load
– Programmable Volume Control (-22 to +20 dB)
– Fully Differential Structure, Input and Output
– 8 mA Drain Current in Active Mode
– Power-down Mode (Consumption Less than 2 µA)
– Minimum External Components (Direct Connection to the Loudspeaker)
• Applications: Mobile Phones, Digital Cameras, PDAs, SmartPhones, DECT Phones,
Music Players
1. Description
The AT73C240 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 90 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 256 or 384 times the input data rate, allowing choice of input data rate
up to 48 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.
The stereo 32 Ohm headset pair of drivers also includes a mixer of a LINEL and
LINER pair of stereo inputs.
Power
Management
and Analog
Companions
(PMAAC)
AT73C240
Audio Interface
for Portable
Handsets
6464A–PMAAC–28-Apr-09