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| AK4951 24位立體聲CODEC解決方案 |
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| 文章來源： 更新時間：2014/10/9 13:30:00 |
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AKM公司的AK4951是集成了麥克風,耳機和揚聲器放大器的低功耗24位立體聲CODEC,取樣頻率從8kHz到48kHz,輸入電路包括麥克風放大器,采用有所有權算法的自動噪音濾波器和高性能自動音量控制(ALC),輸出電路包括無電容耳機放大器和輸出一瓦的揚聲器放大器.主要用在IP照相機,數碼相機,IC錄音機,平板電腦,無線耳機和手持設備.本文介紹了AK4951主要特性,框圖以及評估板AKD4951EN-B主要特性,框圖,電路,PCB元件布局圖和走線圖.
The AK4951 is a low power 24-bit stereo CODEC with a microphone, headphone and speaker amplifiers. The AK4951 supports sampling frequency from 8kHz to 48kHz. It is suitable for a wide range of application from speech signal processing for narrowband, wideband and super wideband to sound signal processing for audio band. The input circuits include a microphone amplifier, an automatic wind noise reduction filter of the proprietary algorithms and a high performance digital ALC (automatic level control) circuit, therefore the AK4951 can record with high-quality sound regardless of whether indoors or outdoors. In addition, the output circuits include a cap-less headphone amplifier with a negative voltage generated by charge pump circuit and a speaker amplifier with 1W output power. It is suitable for various products as well as portable applications with recording/playback function.
The AK4951 are available in a small 32-pin QFN (4mm x 4mm, 0.4mm pitch: AK4951EN) and a 32-pin BGA (3.5mm x 3.5mm, 0.5mm pitch: AK4951EG) packages saving mounting area on the board.
· Applications: IP Cameras, Digital Cameras, IC Recorders, Tablets, Wireless Headphones, Headsets
AK4951主要特性:
1. Recording Functions
• Analog Input
(AK4951EN) 3 Stereo Single-ended inputs with Selectors
(AK4951EG) 2 Stereo and 1 Monaural Single-ended inputs with Selectors
• Microphone Amplifier: +30dB ~ 0dB, 3dB Step
• Microphone Power Supply: 2.0V or 2.4V, Noise Level= −108dBV
• Digital ALC (Automatic Level Control)
- Setting Range: +36dB ~ −52.5dB, 0.375dB Step & Mute
• ADC Performance: S/(N+D): 83dB, DR, S/N: 88dB (MIC-Amp=+18dB)
S/(N+D): 85dB, DR, S/N: 96dB (MIC-Amp=0dB)
• Microphone Sensitivity Correction
• Automatic Wind Noise Reduction Filter
• 5-Band Notch Filter: Include Dynamic Gain Control
• Stereo Separation Emphasis Circuit
• Digital Microphone Interface
2. Playback Functions
• Digital ALC (Automatic Level Control)
- Setting Range: +36dB ~ −52.5dB, 0.375dB Step & Mute
• Sidetone Mixer & Volume Control (0dB ~ −18dB, 6dB Step)
• Digital Volume Control
- +12dB ~ −89.5dB, 0.5dB Step & Mute
• Capacitor-less Stereo Headphone Amplifier
- HP-Amplifier Performance: S/(N+D): 75dB@20mW, S/N: 97dB
- Output Power: 20mW@16Ω
- Pop Noise Free at Power-ON/OFF
• Mono Speaker Amplifier (with Stereo Line Output Switch)
- Speaker Amplifier Performance: S/(N+D): 75dB@250mW, S/N: 99dB
- BTL Output
- Output Power:
(AK4951EN) 400mW@8Ω (SVDD=3.3V), 1W@8Ω (SVDD=5V)
(AK4951EG) 400mW@8Ω (AVDD=3.3V)
• Analog Mixing: BEEP Input
3. Power Management
4. Master Clock:
(1) PLL Mode
Frequencies: 11.2896MHz, 12MHz, 12.288MHz, 13.5MHz, 24MHz, 27MHz (MCKI pin) 32fs or 64fs (BICK pin)
(2) External Clock Mode
Frequencies: 256fs, 384fs, 512fs or 1024fs (MCKI pin)
5. Sampling Frequencies
• PLL Master Mode:
8kHz, 11.025kHz, 12kHz, 16kHz, 22.05kHz, 24kHz, 32kHz, 44.1kHz, 48kHz
• PLL Slave Mode (BICK pin): 8kHz ~ 48kHz
• EXT Master/Slave Mode: 24kHz (1024fs)~
8kHz ~ 48kHz (256fs, 384fs, 512fs), 8kHz
6. Master/Slave Mode
7. Audio Interface Format: MSB First, 2’s complement
• ADC: 16/24bit MSB justified, 16/24bit I2S
• DAC: 16/24bit MSB justified, 16bit LSB justified, 24bit LSB justified, 16/24bit I2S
8. µP I/F:
(AK4951EN) I2C Bus (Ver 1.0, 400kHz Fast-Mode)
(AK4951EG) 3-wire Serial, I2C Bus (Ver 1.0, 400kHz Fast-Mode)
9. Operating Temperature: Ta = −40 ~ 85°C
10. Power Supply
(AK4951EN)
• Analog Power Supply (AVDD): 2.8 ~ 3.5V
• Speaker Power Supply (SVDD): 1.8 ~ 5.5V
• Digital & Headphone Power Supply (DVDD): 1.6 ~ 1.98V
• Digital I/O Power Supply (TVDD): 1.6 or (DVDD – 0.2) ~ 3.5V
(AK4951EG)
• Analog & Speaker Power Supply (AVDD): 2.8 ~ 3.5V
• Digital & Headphone Power Supply (DVDD): 1.6 ~ 1.98V
• Digital I/O Power Supply (TVDD): 1.6 or (DVDD – 0.2) ~ 3.5V
11. Package:
(AK4951EN)
• 32-pin QFN (4 x 4 mm, 0.4mm pitch)
(AK4951EG)
• 32-pin BGA (3.5 x 3.5 mm, 0.5mm pitch)
圖1. AK4951框圖
評估板AKD4951EN-B
The AKD4951EN-B is an evaluation board for the AK4951EN 24bit CODEC with built-in PLL and MIC/HP/SPK Amplifier. The AKD4951EN-B has the interface with AKM’s A/D evaluation boards. Therefore, it’s easy to evaluate the AK4951EN. The AKD4951EN-B also has the digital audio interface and can achieve the interface with digital audio systems via opt-connector.
評估板AKD4951EN-B主要特性:
• Compatible with 2 types of interface
- Direct interface with AKM’s A/D converter evaluation boards
- DIT/DIR with optical input/output
• USB port for board control
圖2. 評估板AKD4951EN-B框圖
圖3. 評估板AKD4951EN-B電路圖(1)
圖4. 評估板AKD4951EN-B電路圖(2)
圖5. 評估板AKD4951EN-B電路圖(3)
圖6. 評估板AKD4951EN-B PCB元件布局圖:頂層
圖7. 評估板AKD4951EN-B PCB元件布局圖:底層
圖8. 評估板AKD4951EN-B PCB走線圖:頂層
圖9. 評估板AKD4951EN-B PCB走線圖:底層 |
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