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WM8985
Multimedia CODEC with Class D Headphone and Line Out
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OLFSON MICROELECTRONICS plc
Production Data, February 2013, Rev 4.7
Copyright 2013 Wolfson Microelectronics plc
DESCRIPTION
The WM8985 is a low power, high quality, feature-rich stereo
CODEC designed for portable multimedia applications that
require low power consumption and high quality audio.
The device integrates preamps for stereo differential mics, and
includes class D and class AB drivers for headphone and
differential or stereo line output. External component
requirements are reduced as no separate microphone or
headphone amplifiers are required.
Advanced DSP features include a 5-band equaliser, an
ALC/limiter for the microphone or line input through the ADC
and a digital playback limiter. Additional digital filtering options
are available in the ADC path, to cater for application filtering
such as ‘wind noise reduction’ and a programmable notch filter.
Highly flexible mixers enable many new application features,
with the option to record and playback any combination of voice,
line inputs and digital audio such as FM Radio or MP3.
The WM8985 digital audio interface can operate in master or
slave mode, while an integrated PLL provides flexible clocking
schemes.
The WM8985 operates at analogue supply voltages from 2.5V to
3.3V, although the digital core can operate at voltages down to
1.71V to save power. Additional power management control
enables individual sections of the chip to be powered down
under software control.
FEATURES
Stereo CODEC:
DAC SNR 98dB, THD -84dB (‘A’ we
ighted @ 48kHz)
ADC SNR 92.5dB, THD -83dB (‘A’ we
ighted @ 48kHz)
Headphone driver wi
th ‘capless’ option
-
40mW/channel output power into 16
/ 3.3V AVDD2
- Class D headphone driver
- Class AB headphone / line Driver
- PSRR 70dB at 217Hz
Stereo, mono or differential line output
Mic Preamps:
Stereo differential or mono microphone interfaces
Programmable preamp gain
Pseudo differential inputs wi
th common mode rejection
Programmable ALC / Noise Gate in ADC path
Low-noise bias suppli
ed for electret microphones
Other Features:
Enhanced 3-D function for
improved stereo separation
Digital play
back limiter
5-band Equaliser (record or play
back)
Programmable ADC High Pass Filter (w
ind noise reduction)
Programmable ADC Notch Filter
Aux inputs for stereo analog input signals or ‘beep’
PLL supporting various clocks betw
een 8MHz-50MHz
Sample rates supported (kHz): 8, 11.025, 16, 12, 16, 22.05,
24, 32, 44.1, 48
Low power, low
voltage
2.5V to 3.6V analogue supplies
1.71V to 3.6V digital supplies
5x5mm 32-lead QFN package
APPLICATIONS
Portable audio player / FM radio
Multimedia Mobile Handsets
