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AKM公司的AK4679是一款內置麥克風放大器、接收放大器、D類揚聲器放大器、耳機放大器、線性放大器的24位立體聲編解碼音頻DSP芯片。本文詳細介紹了AK4679的主要特性、框圖、應用框圖以及采用AK4679芯片設計的評估開發板，通過評估板詳細介紹了AK4679芯片各種模式下的應用設置及測試，評估板主要有評估板框圖、電路原理圖。 The AK4679 is a 24bit stereo CODEC and a built-in Microphone-Amplifier,Receiver-Amplifier, Mono Class-D Speaker-Amplifier, Cap-less Class-G Headphone-Amplifier and Line-Amplifier as well as HF/Audio DSP. The AK4679 features AKM DSP core to deal with hands free function for wide band and dual PCM I/F in addition to audio I/F that allows easy interfacing in mobile phone designs with Bluetooth I/F. The playback features also include 5-band Parametric EQ and Dynamic Range Control; therefore the AK4679 can automatically adjust the volume to a comfortable level that has no distortion and provides great flexibility. The AK4679 is available in a 78pin BGA, tilizing less board space than competitive offerings. AK4679主要特性 CODEC&Amp block 1. Recording Function (Stereo CODEC) • 4 Stereo Input Selectors • 4 Stereo Inputs (Single-ended) or 3 Mono Input (Full-differential) • MIC Amplifier: +24dB ~ −6dB, 3dB step • 2 Output MIC Power Supplies • Digital ALC (Automatic Level Control): +36dB ~ −54dB, 0.375dB Step, Mute • ADC CHARACTERISTICS: S/(N+D): 80dB, DR, S/N: 87dB (MIC-Amp=+18dB)S/(N+D): 80dB, DR, S/N: 92dB (MIC-Amp=0dB) • Stereo Digital MIC Interface • Wind-noise Reduction Filter • Stereo Separation Emphasis • 3-band Programmable Notch Filter • Audio Interface Format: 24/16bit MSB justified, 24/16bit I2S, 16bit DSP Mode 2. Playback Function (Stereo CODEC) • Digital Volume (+6dB ~ −57.0dB, 0.5dB Step, Mute) • Digital ALC (Automatic Level Control): +36dB ~ −54dB, 0.375dB Step, Mute • Stereo Separation Emphasis • Dynamic Range Control • 5-band Parametric Equalizer • Stereo Line Output (Selectable Full-differential / Single-ended) • Mono Receiver-Amp - BTL Output - Output Power: 60mW @ 32Ω - Analog Volume: +12 ~ −30dB & Mute, 3dB Step • Cap-less Stereo Class-G Headphone-Amp - Output Power: 25mW @ 32Ω, 45mW @ 16Ω - Analog Volume: +6 ~ −62dB & Mute, 2dB Step - Zero crossing Detection - Pop Noise Free at Power-ON/OFF • Mono Class-D Speaker-Amp - BTL Output - Short Protection Circuit - Output Power: 1.1W @ 8Ω, SVDD=4.2V, THD+N = 10% 0.89W @ 8Ω, SVDD=4.2V, THD+N = 1% - Analog Volume: +12 ~ −30dB & Mute, 3dB Step - Pop Noise Free at Power-ON/OFF • Audio Interface Format: - 24/16bit MSB justified, 16bit LSB justified, 16/24bit I2S, 16bit DSP Mode 3. Dual PCM I/F for Baseband & Bluetooth Interface • Four sample Rate Converters (Up sample: up to x6: Down sample: down to x1/6) • Sample Rate: - PORTA (Mono): 8 ~ 16kHz - PORTB (Stereo): 8 ~ 48kHz • Digital Volume • Slave Mode • Audio Interface Format: - 16bit Linear, 8bit A-law, 8bit μ-law - Short/Long Frame, I2S, MSB justified 4. Power Management 5. Master Clock(Audio I/F): (1) PLL Mode • Frequencies: 11.2896MHz, 12MHz, 12.288MHz, 13MHz, 13.5MHz, 19.2MHz, 24MHz, 25MHz, 26MHz, 27MHz (MCKI pin) 32fs or 64fs (BICK pin) (2) External Clock Mode • Frequencies: 256fs, 512fs or 1024fs (MCKI pin) 6. Output Master Clock Frequencies(Audio I/F): 32fs/64fs/128fs/256fs 7. Sampling Frequency (Audio I/F) • PLL Slave Mode (BICK pin): 8kHz ~ 48kHz • PLL Master Mode: 8kHz, 11.025kHz, 12kHz, 16kHz, 22.05kHz, 24kHz, 32kHz, 44.1kHz, 48kHz • EXT Master/Slave Mode: 8kHz ∼ 48kHz (256fs), 8kHz ~ 24kHz (512fs), 8kHz ~ 12kHz (1024fs) 8. Audio I/F: Master/Slave mode DSP block 9. Embedded DSP - Flexible programming with built-in program and data memories - Hardware accelerator - Word length: 24bit (Data RAM 24bit floating point) - Multiplier 20 x 20 40bit (double precision available) - Divider 20 / 20 20bit - ALU: 44bit arithmetic operation (with overflow margin 4bit) 24bit floating point arithmetic and logic operation - Program RAM: 4096w x 36bit - Coefficient RAM: 2048w x 20bit - Data RAM: 2048w x 24bit (24bit floating point) - Offset Register: 32w x 15bit - Delay RAM: 16384w x 24bit (24bit floating point) - 5625 steps at fs16KHz, 1875 steps at fs48KHz - Internal clock generator 10. DSP Serial Audio Interface Format - 24bit Left justified, I2S, - 16/24 bit linear, 8bit A-law, 8bit μ-law PCM - Sampling rate 8 KHz ~ 48 KHz - Up/Down sampling rate converter for Port#2 (8KHz → 16KHz) 11. Operational, sleep, suspend mode General 12. μP I/F: I2C Bus (Ver 1.0, 400kHz Fast Mode), SPI (DSP block only) 13. Ta = −30 ~ 85°C 14. Power Supply: • SVDD (SPK/RCV/LINE-Amp): 3.0 ~ 5.5V • AVDD (Analog): 1.7 ~ 2.0V • DVDD (Digital Core): 1.7 ~ 2.0V • PVDD (HP-Amp & Charge Pump): 1.7 ~ 2.0V • TVDDA, TVDDE (Digital I/F): 1.6 ~ 3.6V • VDDE (DSP Core) 1.1 ~ 1.3V 15. Package : 78pin FBGA(4.5 x 4.5 mm, 0.4mm pitch) 
圖1.模擬框圖
圖2.數字框圖
圖3.DSP框圖 采用AK4679評估板參考設計 The AKD4679-A is an evaluation board for AK4679, 24bit stereo CODEC with Microphone/ Receiver/Headphone/ Speaker/ Line amplifier as well as HF/Audio DSP. The AKD4679-A has the one Digital Audio I/F and two PCM I/F. It can achieve the interface with digital audio systems via optical connector and 10pin Port connector. AK4679評估板參考設計的主要特性 DIR/DIT with optical input/output 10pin Header for Digital Audio I/F and PCM I/F (Baseband, Bluetooth) BNC connector for an external clock input 10pin Header for I2C control mode
圖4.參考設計框圖
圖5.參考設計原理圖（1）
圖6.參考設計原理圖（2）
圖7.參考設計原理圖（3）
圖8.參考設計原理圖（4）
圖9.參考設計原理圖（5）
圖9.參考設計原理圖（5） AK4679評估板參考設計 
akd4679-a0-01e.pdf
(1.55 MB)
AK4679數據表
ak4679_f01e.pdf
(1.98 MB)
詳情請見: [url=1.http://www.asahi-kasei.co.jp/akm ... /akd4679-a0-01e.pdf]1.http://www.asahi-kasei.co.jp/akm ... /akd4679-a0-01e.pdf [/url]和 2.http://www.akm.com/datasheets/ak4679_f01e.pdf 來源：網絡 |
