WM8978 查看數據表（PDF） - Wolfson Microelectronics plc

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WM8978

Stereo CODEC With Speaker Driver

Wolfson Microelectronics plc 

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WM8978

Stereo CODEC With Speaker Driver

DESCRIPTION

FEATURES

The WM8978 is a low power, high quality stereo codec

designed for portable applications such as Digital still camera or

Digital Camcorder.

The device integrates preamps for stereo differential mics, and

includes drivers for speakers, headphone and differential or

stereo line output. External component requirements are

reduced as no separate microphone or headphone amplifiers

are required.

Advanced on-chip digital signal processing includes a 5-band

equaliser, a mixed signal Automatic Level Control for the

microphone or line input through the ADC as well as a purely

digital limiter function for record or playback. Additional digital

filtering options are available in the ADC path, to cater for

application filtering such as ‘wind noise reduction’.

The WM8978 CODEC can operate as a master or a slave. An

internal PLL can generate all required audio clocks for the

Codec from common reference clock frequencies, such as

12MHz and 13MHz.

The WM8978 operates at analogue supply voltages from 2.5V

to 3.3V, although the digital core can operate at voltages down

to 1.62V to save power. The speaker outputs and OUT3/4 line

outputs can run from a 5V supply if increased output power is

required. Individual sections of the chip can also be powered

down under software control.

• Stereo Codec:

• DAC SNR 98dB, THD -84dB (‘A’ weighted @ 48kHz)

• ADC SNR 90dB, THD -80dB (‘A’ weighted @ 48kHz)

• On-chip Headphone Driver with ‘capless’ option

- 40mW output power into 16Ω / 3.3V SPKVDD

• 0.9W output power into 8Ω BTL speaker / 5V SPKVDD

- Capable of driving piezo speakers

- Stereo speaker drive configuration

• 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:

• Enhanced 3-D function for improved stereo separation

• Digital playback limiter

• 5-band Equaliser (record or playback)

• Programmable ADC High Pass Filter (wind noise reduction)

• Programmable ADC Notch Filter

• Aux inputs for stereo analog input signals or ‘beep’

• On-chip PLL supporting 12, 13, 19.2MHz and other clocks

• Low power, low voltage

- 2.5V to 3.6V (digital core: 1.62V to 3.6V)

- power consumption <30mW all-on with 2.5V supplies

• 5x5mm 32-pin QFN package

APPLICATIONS

• Stereo Camcorder or DSC

WOLFSON MICROELECTRONICS plc

www.wolfsonmicro.com

Product Preview, January 2005, Rev 1.7

Copyright 2005 Wolfson Microelectronics plc

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