General Description
The AS3418 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 EEPROM can be optionally used to store the microphones gain calibration settings. The
AS3418 can be used in different configurations for best trade-off of noise cancellation, required
filtering functions and mechanical designs.
The AS3418 targeting feed-forward topology is used to effectively reduce frequencies typically up to 2-
3 kHz. The typical bandwidth for a feed-forward system is from 20Hz up to 3 kHz which is lower than
the feed-forward systems.
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.
Applications
● Ear Pieces
● Headsets
● Hands-Free Kits
● Mobile Phones
● Voice Communicating Devices