AKM公司的AK4954A是集成了麦克风,耳机放大器和扬声器放大器的低功耗32位CODEC,输入电路包括麦克风放大器和自动电平控制(ALC)电路,输出电路包括无电容的耳机放大器和扬声器放大器,非常适合于手提音频应用.本文介绍了AK4954A 主要特性,框图,以及评估板AK4954A方框图和电路图.
The AK4954A is a low power consumption 32-bit stereo CODEC with a microphone, a headphone and a speaker amplifiers. The input circuits include a microphone amplifier and an ALC (Automatic Level Control) circuit, and the output circuits include a cap-less headphone amplifier and a speaker amplifier. It is suitable for portable application with recording/playback function. The integrated charge pump circuit generates a negative voltage and removes the output AC coupling capacitors. The speaker amplifier has a wide operating voltage range, which is from 0.9V to 5.5V, enabling a direct drive to batteries. The AK4954A is available in a small 32-pin QFN (4x4mm 0.4mm pitch), utilizing less board space than competitive offerings.
AK4954A 主要特性:
1. Recording Function
• Two Low Noise Microphone Power Supplies
• Stereo Single-ended input with three Selectors
• Low Noise Microphone Amplifier (+26dB/+20dB/+13dB/+6dB/0dB)
• Digital ALC (Automatic Level Control)
(Setting Range: +36dB ∼ −52.5dB, 0.375dB Step)
• ADC Performance: S/(N+D): 88dB, DR, S/N: 97dB (Microphone Amplifier =+20dB)
S/(N+D): 88dB, DR, S/N: 100dB (Microphone Amplifier =0dB)
• Two Types of Decimation Filters
• Overflow Detection
• Wind-noise Reduction Filter
• Stereo Separation Emphasis Circuit
• 5-band Notch Filter
• Digital Microphone Interface
2. Playback Function
• Digital ALC (Automatic Level Control) (Setting Range: +36dB ~ −52.5dB, 0.375dB Step)
• 3-band Dynamic Range Control Circuit
• Digital Volume Control (+6dB ~ −65.5dB, 0.5dB Step, Mute)
• Capacitor-less Stereo Headphone Amplifier
- HP-Amplifier Performance: S/(N+D): 65dB@20mW, S/N: 100dB
- Output Power: 20mW@16Ω
- Pop Noise Free at Power-ON/OFF
• Mono Speaker-Amplifier (with Stereo Line Output Switch)
- SPK-Amplifier Performance: S/(N+D): 70dB@250mW
Output Noise Level: -97dBV
- BTL Output
- Output Power: 400mW@8Ω (SVDD=3.3V)
100mW@8Ω (SVDD=1.5V)
• Beep Generator
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 Slave Mode (BICK pin): 8kHz ∼ 96kHz
• PLL Master Mode: 8kHz, 11.025kHz, 12kHz, 16kHz, 22.05kHz, 24kHz, 32kHz, 44.1kHz, 48kHz, 64kHz, 88.2kHz, 96kHz
• EXT Master/Slave Mode: 8kHz ~ 96kHz (256fs), 8kHz ~ 48kHz (384fs),8kHz ~ 48kHz (512fs), 8kHz ~ 12kHz (1024fs)
6. Master/Slave mode
7. Audio Interface Format: MSB First, 2’s complement
• ADC: 16/24/32-bit MSB justified, 16/24/32-bit I2S
• DAC: 16/24/32-bit MSB justified, 16/24-bit LSB justified, 16/24/32-bit I2S
8. Serial μP I/F: I2C Bus (Ver 1.0, 400kHz Fast-Mode)
9. Ta = −30 ∼ 85°C
10. Power Supply:
• Analog Power Supply (AVDD): 2.5 ~ 3.5V
• Digital Power Supply (DVDD): 1.6 ~ 1.98V
• Digital I/O Power Supply (TVDD): 1.6 or (DVDD-0.2) ~ 3.5V
• Speaker Power Supply (SVDD): 0.9 ~ 5.5V
11. Package: 32-pin QFN (4 x 4mm, 0.4mm pitch)
图1. AK4954A方框图
The AKD4954A-B is an evaluation board for the AK4954A 32bit CODEC with built-in PLL and MIC/HP/SPK Amplifier. On-board USB port enables a GUI on Windows to control various settings. The AKD4954A-B has the interface with AKM’s A/D evaluation boards. Therefore, it’s easy to evaluate the AK4954A. The AKD4954A-B also has the digital audio interface and can achieve the interface with digital audio systems via opt-connector.
图2.AKD4954A-B 评估板框图
图3.AKD4954A-B 评估板电路图(1)
图4.AKD4954A-B 评估板电路图(2)
图5.AKD4954A-B 评估板电路图(3)
