VESTEL MB185 IDTV, Service Manual

Page: 9 / 58

8
4. AUDIO AMPLIFIER STAGES
Figure: The block diagram of the audio part
A. MAIN AMPLIFIER (U118) (8W/10W/12W OPTİONS)
Description
AD82587D is a digital audio amplifier capable of driving a pair of 8 ohm, 20W or a single 4 ohm, 40W
speaker, both which operate with play music at a 24V supply without external heat-sink or fan requirement.
Using I
2
C digital control interface, the user can control AD82587D’s input format selection, DRC (dynamic
range control), mute and volume control functions. AD82587D has many built-in protection circuits to
safeguard AD82587D from connection errors.
Features

16/18/20/24-bit input with I
2
S, Left-alignment and Right-alignment data format

PSNR & DR(A-weighting) Loudspeaker: 97dB (PSNR), 105dB (DR) @ 24V

Multiple sampling frequencies (Fs)

32kHz / 44.1kHz / 48kHz and

64kHz / 88.2kHz / 96kHz and

128kHz/176.4kHz/192kHz

System clock = 64x, 128x, 256x, 384x, 512x, 768x,1024x Fs

256x~1024x Fs for 32kHz / 44.1kHz / 48kHz

128x~512x Fs for 64kHz / 88.2kHz / 96kHz

64x~256x Fs for 128kHz /176.4kHz/192kHz

Supply voltage

3.3V for digital circuit