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WM8985
Multimedia CODEC With Class D Headphone and Line Out
WOLFSON MICROELECTRONICS plc
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Product Brief, January 2006, Rev 1.1
Copyright
2006 Wolfson Microelectronics plc
DESCRIPTION
The WM8985 is a low power, high quality, feature-rich stereo
codec designed for portable multimedia applications requiring
the lowest possible 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 and 3D
enhancement, an ALC/limiter for the microphone or line input
through the ADC and a digital playback limiter. Other
programmable filtering functions are available in the ADC path.
Highly flexible mixing capabilities enable many new application
features, with the option to record and playback any
combination of voice, line inputs and digital audio.
The WM8985 digital audio interface can operate in master or
slave mode, while an integrated PLL provides support for all
commonly used clocking schemes in portable devices.
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 -86dB (`A' weighted @ 48kHz)
ADC SNR 92.5dB, THD -75dB (`A' weighted @ 48kHz)
Class D / AB headphone drivers
Stereo, mono or differential line drivers
40mW per channel output power into 16 / 3.3V AVDD2
Stereo, mono or differential line output
Pop and click suppression
Mic Preamps:
Stereo differential or mono microphone interfaces
Programmable preamp gain
Psuedo differential inputs with common mode rejection
Programmable ALC / noise gate in ADC path
Low-noise bias supplied for electret microphones
Other Features:
3D stereo enhancement
Digital playback limiter
5-band equaliser (record or playback)
Programmable high pass filter (Wind noise reduction)
Programmable notch filter (Additional noise suppression)
Aux inputs for stereo analog input signals
PLL supporting various clocks between 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
Mobile multimedia
Portable audio player / FM radio
WM8985
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Product Brief Rev 1.1 January 2006
2
IMPORTANT NOTICE
Wolfson Microelectronics plc (WM) reserve the right to make changes to their products or to discontinue any product or
service without notice, and advise customers to obtain the latest version of relevant information to verify, before placing
orders, that information being relied on is current. All products are sold subject to the WM terms and conditions of sale
supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation
of liability.
WM warrants performance of its products to the specifications applicable at the time of sale in accordance with WM's
standard warranty. Testing and other quality control techniques are utilised to the extent WM deems necessary to support
this warranty. Specific testing of all parameters of each device is not necessarily performed, except those mandated by
government requirements.
In order to minimise risks associated with customer applications, adequate design and operating safeguards must be used
by the customer to minimise inherent or procedural hazards. Wolfson products are not authorised for use as critical
components in life support devices or systems without the express written approval of an officer of the company. Life
support devices or systems are devices or systems that are intended for surgical implant into the body, or support or
sustain life, and whose failure to perform when properly used in accordance with instructions for use provided, can be
reasonably expected to result in a significant injury to the user. A critical component is any component of a life support
device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or
system, or to affect its safety or effectiveness.
WM assumes no liability for applications assistance or customer product design. WM does not warrant or represent that
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property right of WM covering or relating to any combination, machine, or process in which such products or services might
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Resale of WM's products or services with statements different from or beyond the parameters stated by WM for that
product or service voids all express and any implied warranties for the associated WM product or service, is an unfair and
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ADDRESS:
Wolfson Microelectronics plc
Westfield House
26 Westfield Road
Edinburgh
EH11 2QB
United Kingdom
Tel :: +44 (0)131 272 7000
Fax :: +44 (0)131 272 7001
Email :: sales@wolfsonmicro.com
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