FEATURES

• DAC SNR 99dB (‘A’ weighted), THD -84dB at 48kHz, 3.0V 
• ADC SNR 94dB (‘A’ weighted), THD -82dB at 48kHz, 3.0V
• Microphone interface (Up to four differential microphones)
• 1W Speaker driver
  - 1W into 8ohm BTL speaker at <0.1% THD
  - 80dB PSRR @ 217Hz
  - <1uA leakage with direct battery connection
  - Software-selectable class D or AB mode
  - Filterless connection supported
  - Pop/Click suppression
• Headphone / ear speaker drivers
  - 40mW output power into 16ohm at 3.3V
  - Fully differential and capless modes supported
  - Pop/Click suppression 
• 4 Mono or stereo differential line outputs 
• On-chip FLL provides flexible clocking scheme
• Sample rates: 8, 11.025, 12, 16, 22.05, 24, 32, 44.1, 48kHz 
• Powerful GPIO functions 
• 2 software-programmable DC-DC buck converters (600mA) 
• 4 software-programmable LDO regulators (up to 250mA) 
• Pin selectable start-up sequence and default voltages
• Ultra-low power consumption
  - 5mW analogue voice call
  - 13mW DAC playback to headphones 
• 105-ball 6x6mm BGA package

The WM8400 is a highly integrated audio CODEC and power management unit which provides a cost-effective companion solution for mobile multimedia applications.

Stereo 24-bit sigma-delta ADCs and DACs provide hi-fi quality audio recording and playback, with a flexible digital audio interface supporting most commonly-used data formats and clocking schemes. An integrated low-power FLL, an alternative DAC interface and TDM support provide additional flexibility. 

The ultra-low power audio CODEC is complemented with a powerful 1W speaker driver, which can operate in class D or AB modes. Low leakage, high PSRR and pop/click suppression enable direct battery connection for the speaker supply. 

Multiple microphone or line inputs (mono, stereo, single-ended or differential) can be supported. A programmable high-pass filter is provided to remove low frequency noise from the input signal. 

Four headphone drivers support fully differential headset drive, providing excellent crosstalk performance and bass response, maximising stereo effects, and allowing the removal of large and expensive headphone capacitors. 

The WM8400 incorporates two programmable DC-DC step-down (Buck) converters and four low-dropout (LDO) regulators. The startup sequence and default voltages for the DC-DC converters and two of the LDOs are pin selectable; All the regulators are software programmable. The DC-DCs, LDO1 and LDO2 are intended to power the MMP sub-system, whilst the remaining LDOs are specifically designed to power the on-chip audio CODEC. 

The WM8400 is supplied in a 6x6mm 105-ball BGA package, ideal for use in portable systems. The WM8400 forms part of Wolfson’s AudioPlus^TM series of audio and power management solutions.