ams introduced the AS3421 and AS3422, single chip ANC solutions with integrated speaker driver ICs, which make it easier for manufacturers of Bluetooth headsets, headphones and earpieces to implement Active Noise Cancellation.Wireless headsets, which may be linked over the air to devices such as mobile phones and portable media players, are often used in noisy environments such as cars, airplanes, office buildings and public places. The successful implementation of ANC dramatically reduces the perceived volume of external noise, enabling the desired receive-path audio signal to be heard against a nearly silent background. Single chip ANC solutions with integrated speaker driver ICs process external noise sensed by a microphone embedded in the headset, and generate a noise-cancelling signal, while amplifying the desired audio signal with very low levels of distortion.
Ams’ portfolio of ANC driver ICs is suited to wired headphones, headsets and ear-phones. Now, with the introduction of the AS3421/22, it has delivered an ANC solution optimized for use in wireless headsets, many of which use Bluetooth to provide an RF channel between the host device and the headset. Low power consumption and long battery life are particularly important requirements in wireless head-sets, and the all-analog design of the AS3421/22 is markedly more efficient than DSP-based (digital) speaker driver ICs. The devices draw just 7mA at 1.5V in stereo ANC mode, and <1µA in quiescent mode. They also implement an ultra-low power ANC-bypass mode when the user selects the playback-only function. In addition, the AS3421/22 devices offer fully differential stereo line inputs to match the differential line outputs from typical Bluetooth-based headset systems-on-chip, combining outstanding audio quality with high performance noise reduction of typically more than 25dB. The AS3421 is housed in a 4 x 4mm QFN24 package while the AS3422 uses a 5x 5mm QFN32 package.
