AS3412 EK-ST: Class AB, 50mW @ 16Ω, Headphone Amp

The AS3412 is a speaker driver with Ambient Noise Cancelling function for headsets, headphones or ear pieces. They are intended to improve quality of e.g. music listening, a phone conversation etc. by reducing background ambient noise.

The fully analog implementation allows the lowest power consumption, lowest system BOM cost and most natural received voice enhancement otherwise difficult to achieve with DSP implementations. The device is designed to be easily applied to existing architectures.

An internal OTP-ROM can be optionally used to store the microphones gain calibration settings. The AS3412 can be used in different configurations for best trade-off in terms of noise cancellation, required filtering functions and mechanical designs. The AS3412 targeting feed-forward topology is used to effectively reduce frequencies typically up to 2-3 kHz.

The filter loop for the system is determined by measurements, for each specific headset individually, and depends very much on mechanical designs. The gain and phase compensation filter network is implemented with cheap resistors and capacitors for lowest system costs.