WM8731: CODEC with headphone driver
Description
The WM8731 or WM8731L (WM8731/L) are low power stereo CODECs with an integrated headphone driver. The WM8731/L is designed specifically for portable MP3 audio and speech players and recorders. The WM8731 is also ideal for MD, CD-RW machines and DAT recorders.
Stereo line and mono microphone level audio inputs are provided, along with a mute function, programmable line level volume control and a bias voltage output suitable for an electret type microphone.
Stereo 24-bit multi-bit sigma delta ADCs and DACs are used with oversampling digital interpolation and decimation filters. Digital audio input word lengths from 16-32 bits and sampling rates from 8kHz to 96kHz are supported.
Stereo audio outputs are buffered for driving headphones from a programmable volume control, line level outputs are also provided along with anti-thump mute and power up/down circuitry.
The device is controlled via a 2 or 3 wire serial interface. The interface provides access to all features including volume controls, mutes, de-emphasis and extensive power management facilities. The device is available in a small 28-lead SSOP package or the smaller 28 lead quad flat leadless package (QFN).
Features
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Stereo Audio Codec with Integrated Headphone Driver (50mW on 16W @ 3.3V)
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1.42 – 3.6V Digital Supply
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2.7 – 3.6V Analogue Supply (standard)
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1.8 – 3.6V Analogue Supply (’L’ version)
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Playback Mode Power Consumption < 18mW
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100dB SNR (‘A’ weighted @ 48kHz) DAC
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90dB SNR (‘A’ weighted @ 48kHz) ADC
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Sampling Frequency: 8kHz – 96kHz
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Master or Slave Clocking Mode
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USB clocking mode can generate all common MP3 sample rates (incl. 441.kHz) directly from USB clock
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Output Volume and Mute Controls
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Microphone Input and Electret Bias with Side Tone Mixer
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Selectable ADC High Pass Filter
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2 or 3-Wire MPU Serial Control Interface
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Programmable Audio Data Interface Modes
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28-Pin SSOP Package



