First USB microphone ADC with integrated preamplifier, gain calibration and sync control

The isochronous, full-speed USB interface provides universal compatibility with major CE devices and appliances, making it easy to add state-of-the-art voice capture capability to existing hardware and OS platforms. The integrated Sync Control feature eliminates clock jitter by synchronizing the ADC to the playback clock domain, a critical advantage for systems running acoustic echo cancellation algorithms.

There are a total of four independent voice input channels with integrated anti-aliasing filters for microphone array applications. The major challenge with microphone arrays, which are used for voice localization and beamforming, is unmatched microphones in an assembled microphone module. This problem often leads to inaccurate estimation of the shape of the beam, and issues in noise suppression and precision localization. The CX20820 includes a self-gain calibration feature that corrects for the mismatch down to maximum 1 dB variance—another innovation in the CX20820 that stands out from the typical microphone ADC.

The CX20820 is a purpose-built, four- channel microphone ADC designed to support voice-interactive applications that consumers are now expecting on their Smartphones and Smart TVs for casual use cases such as Wake-On-Voice, Voice Search, and Voice Control. “Conexant is the leading supplier for Voice Input solutions,” noted Saleel Awsare, vice president and general manager at Conexant. “We invest dedicated and focused R&D effort in creating a portfolio of voice input components and SoC products that are uniquely positioned in the audio market to address the growing demand for voice.”

Key features:

-Full speed, USB UAC interface
-16 bit, 4-channel ADCs
-Internal Microphone Array Gain Calibration
-Sync Control
-76 QFN ROHAS package

Early engineering samples are available in small quantities today at $1.50 each in 10Ku quantities.