AKM AK4691扬声器放大方案

AKM 公司的AK4691是低能耗配有麦克风/耳机/扬声器放大器的2声道ADC和4声道DAC.录音部分支持4路输入,并有3个 输入选择器,可选用作内部/外部MIC和LINE,输出功率可用来驱动麦克风,耳机放大器和自动电平控制(ALC)电路.播放部分包括有线输出放大器,耳机放大器和扬声器放大器,可广泛应用在数字摄像机,数码相机等手提音频设备.本文介绍了AK4691的主要性能特性,方框图以及典型应用电路图;同时还介绍了AK4691评估板AKD4691的主要性能和详细电路图.

AK4691低能耗2声道ADC和4声道DAC配有麦克风/耳机/扬声器放大器
The AK4691 is a 16bit, 4ch ADC and 2ch DAC with Microphone-Amplifier, Headphone-Amplifier, and Speaker-Amplifier. The recording block corresponds to supports 4-channel inputs, and also has 3-input selector for Internal/External MIC and LINE, output power for Microphone, Pre-Amp, and ALC (Automatic Level Control) circuit. The playback bock has Lineout-Amplifier, Headphone-Amplifier, and Speaker-Amplifier. The AK4691 is suitable for portable applications such as built-in LCD. The AK4691 is available in a 57pin BGA, utilizing less board space than competitive offerings.

Applications: Digital video cameras, Digital still cameras and Array microphones

Recording Function
4-channel Single-ended Pre-Amp
(Pre-Amp Gain: 0dB, +18dB, +20dB, +24dB or +28dB)
2-channel Line Input
3-input Selector (Internal MIC, External MIC or LINE)
4-channel Digital ALC (Automatic Level Control)
ADC Performance: S/(N+D): 82dB, DR, S/N: 90dB (Pre-Amp=+24dB)
S/(N+D): 85dB, DR, S/N: 90dB (LINE)
Wind-noise Reduction Filter
Stereo Separation Emphasis
Fade-in/out Function
Playback Function
Digital De-emphasis Filter (tc=50/15 μs, fs=32kHz, 44.1kHz, 48kHz)
Digital Volume (+12dB ~ - 115.0dB, 0.5dB Step, Mute)
Digital ALC (Automatic Level Control)
Stereo Separation Emphasis
Stereo Line Output
- Performance : S/(N+D): 85dB, S/N: 90dB
- Output Level: -3.9dBV @ AVDD=LVDD=3.0V, LVOL=0dB
+2dBV @ AVDD=3.0V, LVDD=4.5V,
LVOL=+5.9dB
Stereo Headphone-Amp
- S/(N+D): 70dB, S/N: 90dB
- Output Power : 58mW @ 16Ω (LVDD=3.3V)
- Pop Noise Free at Power ON/OFF
Mono Speaker-Amp
- S/(N+D): 50dB@240mW, S/N: 90dB
- BTL Output
- Output Power: 400mW @ 8Ω (SVDD=3.3V)
Analog Mixing
Power Management
Master Clock :
(1) PLL Mode
Frequencies :
11.2896MHz, 12MHz, 12.288MHz, 13.5MHz, 24MHz, 27MHz  (MCKI pin)
1fs (LRCK pin)
32fs or 64fs (BICK pin)
(2) External Clock Mode
Frequencies : 256fs, 512fs or 1024fs (MCKI pin)
Output Master Clock Frequencies : 32fs/64fs/128fs/256fs
Sampling Rate:
PLL Slave Mode (LRCK pin): 7.35 kHz ~ 48k Hz
PLL Slave Mode (BICK pin): 7.35 kHz ~ 48k Hz
PLL Slave Mode (MCKI pin):
8kHz, 11.025kHz, 12kHz, 16kHz, 22.05kHz, 24kHz, 32kHz,
44.1kHz, 48kHz
PLL Master Mode:
8kHz, 11.025kHz, 12kHz, 16kHz, 22.05kHz, 24kHz, 32kHz,
44.1kHz, 48kHz
EXT Slave Mode:
7.35 kHz ~ 48kHz (256fs), 7.35 kHz ~ 48kHz (512fs),
7.35kHz ~ 13kHz (1024fs)
μP I/F: 3 -wire Serial , I2 C Bus (Ver 1.0, 400kHz Fast-Mode)
Master/Slave mode
Audio Interface Format: MSB First, 2s complement
ADC: 16bit MSB justified , I2S, TDM Mode
DAC: 16bit MSB justified, 16bit LSB justified , 16-24bit I2S, TDM Mode
Ta = - 30 ~ 85 ° C
Power Supply Voltage:
Analog (AVDD), Digital (DVDD): 2.6 ~ 3.6V
MIC ( MVDD): 2.6 ~ 5.5V
Lineout & Headphone ( LVDD): 2.6 ~ 5.5V
Speaker (SVDD): 2.6 ~ 3.6V
Digital I/F ( TVDD1, TVDD2): 1.6 ~ 3.6V
Package: 57pin BGA (5mm x 5mm, 0.5mm pitch, height: 1.0mm)
Evaluation Board: AKD4691
AK4691 BLOCK DIAGRAM



图1. AK4691方框图




图2. AK4691典型应用电路图

评估板AKD4691
The AKD4691 is an evaluation board for the AK4691, 16bit 4ch ADC + 2ch DAC with built-in MIC/Headphone/Speaker Amplifier. The AKD4691 can evaluate A/D converter and D/A converter separately in addition to loop-back mode (A/D → D/A). The AKD4691 also has the digital audio interface and can achieve the interface with digital audio systems via opt-connector.



图3.AKD4691方框图



图4. 评估板AKD4691电路图(1)



图5.评估板AKD4691电路图(2)



图6.评估板AKD4691电路图(3)



图7.评估板AKD4691电路图(4)