Conexant公司的CX20709是片上扬声器(SPoC)解决方案,集成了有有所有权的DSP,CODEC,D类驱动器,以及I2S,I2C和USB接口,具有音频和语音增强算法,能把音频娱乐和语音通信融合在一起,主要用在全合一的扬声器系统,LCD显示器,家庭自动化/通信,WiFi 手机,MID, 手持导航,手持媒体播放器,嵌入式应用,多媒体IP电话等.本文介绍了CX20709主要特性, 接口方框图, 应用示意图以及CX20709-EVK 评估板主要特性.
CX20709 Speakers-on-a-Chip with On-chip Voice/Audio DSP, Integrated I2S/I2C/USB Codec, and Class-D Amplifier
Cost-effective single-chip solution enables superior audio and voice quality
The CX20709 is one of Conexant’s Speakers-on-a-Chip (SPoC) solutions with the proprietary on-chip Digital Signal Processor (DSP), Codec, Class-D driver, and I2S, I2C, USB interfaces in a cost-effective single-chip package. The solution features a suite of turnkey audio and voice enhancement algorithms designed for convergence audio entertainment and voice communication applications, such as All-In-One Speakers/Docking systems, Portable Multimedia/Navigation Devices, Smart Home Intercom System, and Unified Communication Peripherals. This product is part of the CX2070x SPoC family, which includes CX20702, CX20703, CX20704, CX20705, CX20706 and CX20707.
The device features multiple high performance 24-bit DACs for 2.1CH speaker output, multiple 24-bit high performance ADCs supporting mono or array microphones and up to three stereo line inputs, capless headphone output, support for dual bi-directional 12S, PCM, S/PDIF-out with independent sampling rates, and a range of digital and analog input/output channel selections for flexible routing and mixing. Different audio sampling rates ranging from 8 kHz to 96 kHz are generated directly from the master clock without the need for external PLL. The power-efficient Class-D amplifier drives a maximum of 2.5 W (average) stereo from the integrated amplifier. The device can be controlled and configured by both read and write capability through I2C and Serial Peripheral Interface (SPI). The optional USB interface supports full speed, and is USB 2.0 Audio Class compliant for both control and data.
The on-chip Digital Signal Processor (DSP) runs a suite of innovative Conexant proprietary voice processing algorithms and 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. Key audio innovations include Subband Acoustic Echo Cancellation, Noise Reduction, Stereo Beam-forming, Subband Line Echo Cancellation, Equalizer, Dynamic Range Compression, Digital Crossover, and 3D effects. The embedded SPoC Configuration Toolbox allows for fast configuration and performance optimization.
The CX20709 turnkey solution eliminates the need for a multiple-chip reference design, making it easy and economical for manufacturers to design products for high quality audio and voice applications. A complete evaluation kit with reference board and all the necessary technical documents and software is available.
The SoC is packaged in an environmentally-friendly, RoHS/Green-compliant 76-pin QFN (Quad Flat No leads) package.

CX20709特性:

CODEC
• 4-wire and 5-wire digital audio I/O (I2S/ PCM/SPDIF), supporting full duplex independent sampling rates
• One 3-wire I2C or 4-wire SPI slave interface for external MCU
• Eight GPIO pins
• 2.5 W x 2 BTL stereo Class-D speaker amplifier
• USB 2.0 Compliant Audio Class Interface (high speed data and control)
• Output for external feedback-less type Class-D amplifier
• Spread Spectrum for filter-less, low EMI output
• Three single-ended stereo or one differential stereo analog audio input converted to digital format
• Two microphones interfaces with on-chip bias supply
• Integrated 50 mW headphone driver with jack sense
• Differential line out
• Separately mixed mono line-output
• Three 24-bit DAC/four ADC, SNR 102 dB, THD - 92 dB at 48 kHz 3.3 V
• Audio sample rate: 8, 11.025, 12, 16, 22.05, 24, 32, 44.1, 48, 64, 88.2, 96 kHz
• 90 dB dynamic range with 0.01percent THD+N at 4 Ω load
• 10-bit ADC multiplexed to support analog volume potentiometer and DC level detection
• Flexible power management
• Variable master clock rates
DSP
• Subband acoustic echo suppression and cancellation
• Stereo beam-forming
• Noise reduction
• Dynamic loudness adaptor
• Mic auto gain control
• Subband line echo cancellation (two-way intercom applications)
• Digital parametric equalizer (10 bands/ channel)
• Dynamic range compression
• 4th Order Digital Crossover for Subwoofer Line-out
• 3D Expander (Phantom mode and Immersion mode)
SPoC Configuration Toolbox
• Fast configuration tool via USB-to-I2C from PC
• Device configuration and DSP parameter adjustment
• Output log for convenient MCU programming
CX20709主要特性:
I2S/USB Codec with on-chip DSP and Class-D amplifier
On-chip proprietary audio and field-proven voice enhancement DSP algorithms
Contains multiple high-performance 24-bit DACs/ADCs
Subband acoustic echo cancellation
Subband line echo cancellation (two-way intercom applications)
3D Expander (Phantom and Immersion mode)
BrightSound™
Flexible analog and digital input/output interfaces
Flexible power management
CX20709主要优势:
Highly integrated single-chip solution reduces external BOM components and cost
Turnkey single source for DSP algorithms; reliable performance with low risk
Provides 2.1CH speaker output and supports mono or array microphones
Eliminates speaker-to-microphone feedback
Eliminates echo from twisted-pair crossover on a full duplex two-wire hybrid network
Enhances audio experience - widens the sound output from narrowly separated speakers; repositions the sound for an immersive effect
Dramatically improves audio quality and reduces speaker clipping
Compatibility with host processor and external peripherals
Low power consumption - <5mW stand-by mode or <1mW deep sleep mode
CX20709应用:
• All-in-One Speakers System
• LCD Display/Sound Bar
• Home Automation/Intercom
• Wi-Fi® Phone/Smart Phone Docking Systems
• Mobile Internet Devices, Portable Navigation Devices, Portable Media Players
• Multimedia IP phone
• Telepresence/Unified Communication Device
• Embedded applications
• Intercom systems
• Full-duplex Hands-free Telephony
• Unified Communication Peripherals