CX20812/CX20813 High-Definition Voice Capture IC AudioSmart™ Product Brief Two-Channel High Performance Microphone Array ADCs with Programmable Pre-amplifier and Class D PWM Out Product Overview The CX20812 is a high performance, analog front-end, high-definition voice capture IC for voice recognition, control, and conferencing applications. The device supports a microphone array with up to two synchronized ADCs and programmable pre-amplifiers. Each preamplifier has a dedicated micbias supply that eliminates crosstalk. The entire input path guarantees 106dB dynamic range, which allows the voice system to use the full performance of a high SNR microphone using low microphone boost to prevent microphone saturation. This path is critical for far field applications, and also ideal for compact speaker-phone designs where the microphone and speakers are in close proximity. The CX20812 features high-resolution digital and analog gain control over a wide range, allowing a selection of optimal operating points for microphones with a wide range of sensitivity. The smooth gain ramping circuit allows dynamically adjusting microphone gain without introducing audible artifacts. The CX20813 adds a mono digital PWM class D amplifier for ringer and audio playback functions. The class D amplifier output drives up to 1W-rms into a 4 load. The PWM output can be configured to support an external output stage amplifier for higher output power applications. The CX20812 and CX20813 are the industry's first dedicated voice capture ICs that are designed to service the most demanding voice interactive applications. Key Features • • • • • • • Two high-performance ADCs with pre-amplifiers Microphone/line input support Dynamic range: 106dB THD+n: –85dB measured at –1dBFS Supported audio sample rates of: 8kHz, 16kHz, 22.05kHz, 24kHz, 32kHz, 44.1kHz, 48kHz, 88.2kHz, and 96kHz ADCs channels mixer Two micbias voltages from 1.5V to 4V Conexant Confidential • www.conexant.com • 004-1213PBR00 • • • • • • • Digitally controlled gain adjustment: – Analog gain 0dB to 30dB with 0.5dB steps – Digital gain –74dB to 12dB with 0.125dB steps – Gain ramping minimizes audible artifacts when gain switching Integrated offset calibration to minimize the BOM Two programmable biquads to configure Q-notch, HPF, or other type of filters Integrated LDO allows single supply (3V~5.5V) to minimize the BOM Integrated charge pump for power management Consumes very low power; 0.02mW in sleep mode Digital class D PWM output up to 1W into 4 speakers on the CX20813 Applications • • • Voice interactive products Voice capture systems In-vehicle infotainment System Block Diagram CX20812/CX20813 High-Definition Voice Capture IC | AudioSmart™ Product Brief Additional Features • Configurable low power and high performance modes • Four-wire audio I2S/PCM output supports the four ADC’s data, and also supports TDM • Three-wire audio I2S/PCM input on the CX20813 that supports mono DACs • • I2S master and slave mode support Integrated PLL supports 900kHz up to 50MHz input clocks in master mode, and 256Fs in slave mode • Two-wire I2C slave interface for external MCU Four general GPIOs Support of 1.8V and 3.3V digital I/Os CX20812: 48 QFN, 6x6 CX20813: 60 QFN, 7x7 • • • • Ordering Information Part Number Description CX20812-11Z Two-channel input only. Package 6x6mm QFN CX20813-11Z Two-channel input with playback 7x7mm QFN digital PWM class D amplifier. Electrical Characteristics TA = 25 oC, AVDD = DVDD = 3.3 V, 1kHz signal, fs = 48kHz, PGA gain = 0dB Parameter Minimum Typical Maximum Unit Comments Recommended Operating Conditions Analog Voltage Supply (Input to LDO) 3.15 - 5.25 V LDO and charge pump integrated. Digital Core Power Supply - 1.2 2 V LDO and charge pump integrated. Digital I/O Supply—3.3V 3.15 3.3 3.45 V 3.3V signaling levels. Digital I/O Supply—1.8V 1.71 1.8 1.89 V 1.8V Signaling level. Ground (AGND, PGND, DGND) - 0 - - - SNR (A-weighted) - 106 - dB Microphone gain = 6dB (measured at –60dBFS input). THD - –89 - dB Microphone gain = 0dB (measured at –1dBFS input). Microphone Input Power Supply Rejection Ratio - 90 - dB At 217Hz. Mute Attenuation 80 - - dB - Input Resistance 8 - 500 k Input PGA gain setting dependent. Micbias Bias Voltage 1.5 - 4 V - Bias Current - - 10 - - Noise in the Signal Bandwidth - –116 - dBV 20kHz bandwidth. PWM (CX20813 Only) Full-scale Output - 2 - Vrms Scales with supply. SNR (A-weighted) - 89 - dB AVDD = 3.3V, 4 load. THD+n - –53.1 - dB AVDD = 3.3V, 4 load. www.conexant.com Headquarters: 1901 Main Street, Suite 300 Irvine, CA,92614 General Information: U.S. and Canada: 888-855-4562 | International: 1 + 949-483-3000 © 2014 Conexant Systems, Inc. All rights reserved. 004-1213PBR00