Wolfson 公司的WM2002是采用Wolfson myZoneTM环境噪音消（ANC）除技术的立体声耳机驱动器，可采用单端或BTL输出配置，支持模拟播放或语音输入，模拟或数字麦克风。WM2002集成了功率管理，包括DC/DC转换器，电荷泵和LDO稳压器，采用单节AAA电池供电。环境噪音可降低25dB(典型值),降噪带宽(40Hz -4kHz) ，BTL驱动的THD+N可达-80dB。主要用在带ANC的手机，耳机以及蓝牙单声道/立体声手机。本文介绍了WM2002主要特性，方框图，典型应用框图以及推荐外接元件数值和DC1升压转换器和电荷泵外接元件数值。

Stereo Headphone Driver with Wolfson myZoneTM Ambient Noise Cancellation

The WM2002 is a low power, high quality stereo headphone driver, delivering Wolfson’s patented myZoneTM ambient noise cancellation in a single-ended or BTL (bridge-tied-load) output configuration. The WM2002 supports analogue playback or voice input, and analogue or digital microphone inputs for noisemonitoring microphones.

Designed for embedded applications or incorporated within a stand-alone headset or headphone, the Wolfson myZone™ ANC noise cancellation engine performs ambient noise cancellation during a voice call or during music playback.

The ambient noise input is supported via single-ended or differential analogue microphone interfaces; digital microphone input is also supported. Up to 10 noise input microphones can be supported at once.

The WM2002 provides integrated power management, comprising a DC-DC converter, Charge Pump and LDO Regulators. Many different power supply configurations are thus supported. The entire device can be powered from a single cell AAA battery, or from 2xAAA cells, or from an external regulated supply.

System clocking is achieved using an on-chip oscillator. An external clock can be connected directly, if available. The WM2002 is configured using programmable settings stored in an integrated non-volatile memory. The configuration stored in the OTP memory is enabled automatically at start-up. If required, the WM2002 can also be configured using register control accessed using a 2-wire serial control interface.

WM2002主要特性：

Wolfson myZone™ Ambient Noise Cancellation (ANC)

- >30dB (peak), 25dB (typical) ambient noise reduction*

- Wide noise cancellation bandwidth (40Hz to 4kHz)*

- * depending on acoustic configuration

- Multiple banks of ANC coefficients can be programmed to support different operating conditions

Audio inputs

- Up to 10 analogue or digital microphones

- Single-ended or differential analogue microphone input

- 2 single-ended or 1 differential line input per channel

Headphone driver (LDO4VOUT = 1.8V)

- 45mW per channel into 16ohm load

- 22mW per channel into 32ohm load

- Single-ended or differential (BTL) drive configuration

- -80dB THD+N for differential (BTL) drive

Integration

- On-chip DC-DC boost converter, charge-pump and LDOs

- Flexible power supply options, including single cell battery (1 x AAA battery) or (2 x AAA/AAAA)

- Internal crystal oscillator

Miscellaneous

- Monitor pin to select mute / talk-through modes

- LED driver

- Tone generator for audible status indication

- Pop and click noise protection circuit

- RFI suppression

- 48-pin QFN package (7 x 7 x 0.75mm, 0.5mm pitch)

WM2002应用：

“Pod-style” stereo ear-buds, headsets, headphones with ANC

“Supra-Aural” stereo headphones with ANC

Mono/Stereo Bluetooth headsets with ANC