Audio Embedded Audio CX20745 I2S Audio Codec SoC with Capless Headphone, Digital Microphone and Integrated Stereo Class-D Amplifier Low-power, cost-effective single-chip solution enables superior audio The CX20745 is one of Conexant’s embedded audio solutions specifically designed for compact consumer electronics such as mobile Internet devices, smartbooks, and Web tablets. The low-power, energy-efficient device features a proprietary inline configurable Digital Signal Processing (DSP), Codec, stereo filterless Class-D amplifier with Spread Spectrum Electromagnetic Interference (EMI) dispersion technology, capless headphone driver, and I2S interface in a cost-effective single-chip package. The DSP runs a suite of turnkey audio post-processing effects for enhanced sound quality. The chip features high performance multibit DACs for speaker output, multi-bit high performance ADCs supporting mono or array microphones or one stereo line input, capless headphone output, and a range of digital and analog input/output channel selections for flexible routing and mixing. The CX20745 contains a pair of ProCoustic™ headphone drivers supporting a full-range frequency response at 98 dB dynamic range, and headset jack support, which lowers Bill of Materials (BOM) cost by eliminating the need for external jack sense, external amplifier, and Direct Current (DC)-blocking capacitors. The codec supports four conductor-type Open Mobile Terminal Platform (OMTP) headset jacks with bias sensing for external headset control. All output ports feature Conexant’s PopShield DC cancellation to eliminate audio pops and clicks that often occur during power state transitions. Class-D amplifier drives up to 2 W into a 4Ω speaker with 5 V supply or 1 W with 3.3 V supply. The SPoC operates at 2.2 mA in standby mode and 0.5 mA in sleep mode, which enhances battery-operated devices through low power consumption and low heat generation. The device supports industrial temperatures of -40~85C. Audio Speakers-on-a-Chip The DSP runs a suite of audio post processing effects that dramatically improves sound quality and frees-up processing power for other applications without compromising on cost and future firmware scalability. The fully configurable hardware Equalizer, Dynamic Range Control, and Microphone Automatic Gain Control improves performance, maximizes output volume, protects the speakers, and enables far-field audio pick-up by broadening the sound-capture radius for enhanced audio quality. The CX20745 also features Hardware Digital Volume Control, a feature similar to an infinite volume control knob commonly found in high-end audio-visual equipment. The CX20745 turnkey solution eliminates the need for a multiple-chip reference design and includes Conexant’s software driver and design support making it easy and economical for manufacturers to design products for high quality audio applications. The SoC is packaged in an environmentallyfriendly, RoHS/Green-compliant 48-pin QFN (Quad Flat No-leads) package. Applications • Consumer Electronics Embedded Audio • Mobile Internet Device • Web Tablet Device • Smartbook The CX20745’s power-efficient and flexible Key Features Benefits Class-D amplifier with Spread Spectrum FIlterless, low EMI, and power-efficient speaker amplifier with ample power to drive up to 2W/ch On-chip Digital Signal Processing Audio enhancement and optimization for speakers and microphones Multi-bit DACs/ADCs with fully differential internal signaling High performance audio fidelity with low external interference PopShield with DC offset cancellation Pop and Click suppression and cancellation Low power stand-by and sleep <2.2.mA stand-by (Idle) mode or <.5mA sleep mode Part Number CX20745 Description I2S Audio Codec SoC with Capless Headphone, Digital Microphone and Integrated Stereo Class-D Amplifier Audio Embedded Audio CX20745 Features CODEC • Stereo 8/16/24-bit DAC supports sample rates capable of 8, 8.018,11.025, 12, 16, 16.0364, 22.05, 24, 32, 44.1, 48, 88.2, and 96 kHz, depending on the master clock – 98 dB Dynamic Range – -85 dB THD • Stereo 8/16/24-bit ADC supports sample rates capable of 8, 8.018,11.025, 12, 16, 16.0364, 22.05, 24, 32, 44.1, 48, 88.2, and 96 kHz, depending on the master clock • Supports master clock of 24.576 MHz and 22.5792 MHz • Data interface: I2S that can be converted to PCM, I2S/PCM are slave only • Control Interface: I2C slave only • Audio ports: – Stereo analog input port supporting up to one single-ended stereo microphone, one differential mono microphone, one single-ended stereo line-In, or one differential mono line-in SENSE_A MIC BIAS – 4-conductor OMTP headset set jack compliant with integrated in-line command sensing. Mic bias sensing capability for external headset control. Supports sense and switching between MIC and GND pins – Stereo class-D amplifier – Stereo capless headphone port – Single-ended analog line output (stereo) – Digital microphone input (stereo) • Class-D amplifier with the following modes of operation: – Up to 2 W per channel into 4Ω with 5 V supply – Up to 1 W per channel into 4Ω with 3.3 V supply – Spread Spectrum for EMI protection on the class-D amplifier • Line-In loopback mode, where the input signal will loop back to the DAC for playback with EQ • PopShield active anti-pop circuit • Device can operate in 3.3 V • Integrated LDO converting 5 V to 3.3 V, and 3.3 V to 1.8 V • PDM digital MIC interface supporting clock frequency of 3.072 MHz and 1.536 MHz • Supports industrial temperatures of -40~85C • Jack sense supporting up to four jacks • Codec provides independent gain and mute control for both DAC and ADC • Four General purpose GPIOs – GPIO1 and GPIO2 can be configured for “Infinity Volume Control” using a rotary encoder DSP • Digital parametric equalizer (5 bands/ channel) • Dynamic range control including compressor and limiter • Microphone automatic gain control Power Management • Idle Mode: 2.2 mA with 10 ms fast resume • Sleep Mode: 0.5 mA (digital supply only) with 200 ms resume Jack Sense 50mW Capless HP Out 32 Ω 50mW Capless HP Out 32 Ω Bias Generator 2W Class-D 4Ω Line/Mic In M ADC AGC Σ M + Line/Mic In M ADC Σ M AGC Five Band EQ DRC Five Band EQ DRC PWM Out DAC Fault 2W Class-D 4Ω DAC 10K Line 5.0V_IN 3.3V LDO 3.3V_FILT 3.3V_IN TX_DAT TX_WS/SYNC 1.8V_FILT 1.8 V LDO PCM/I2S BIT_CLK PCM/I2S RX_WS/SYNC I2C Slave RX_DAT Clock Circuitry BIT_CLK Master Clock M Digital Mic SDA MIC Clock PWM Out 10K Line M MIC Data SCL CX20745 System Block Diagram The CX20745 is offered in a 48-pin QFN package Conexant Product Portfolio Conexant’s comprehensive product portfolio includes solutions for imaging, audio, video surveillance, and embedded modem applications. © 2010 Conexant Systems, Inc. All Rights Reserved. Conexant and the Conexant logo are registered trademarks of Conexant Systems, Inc. All other trademarks are owned by their respective owners. Although Conexant strives for accuracy in all its publications, this material may contain errors or omissions and is subject to change without notice. This material is provided AS IS and without any express or implied warranties, including merchantability, fitness for a particular purpose and non-infringement. Conexant shall not be liable for any special, indirect, incidental or consequential damages as a result of its use. 10-2947 www.conexant.com General Information: U.S. and Canada: (888) 855-4562 International: 1+ (949) 483-3000 Headquarters 4000 MacArthur Blvd. Newport Beach, CA 92660 Doc# PBR-202653