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WM8737CLGEFL 参数 Datasheet PDF下载

WM8737CLGEFL图片预览
型号: WM8737CLGEFL
PDF下载: 下载PDF文件 查看货源
内容描述: 用麦克风前置放大器的立体声ADC [Stereo ADC with Microphone Preamplifier]
分类和应用: 商用集成电路放大器
文件页数/大小: 40 页 / 413 K
品牌: WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
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WM8737L  
Production Data  
Test Conditions  
DCVDD = 1.5V, AVDD = MVDD = 3.3V, TA = +25oC, 1kHz -1dBFS signal, Normal Power Mode, fs = 48kHz, PGA gain = 0dB, 24-  
bit audio data, unless otherwise stated.  
PARAMETER  
SYMBOL  
TEST CONDITIONS  
MIN  
–3%  
–3%  
TYP  
MAX  
+3%  
+3%  
UNIT  
Analogue Reference Levels  
Mid-rail Reference Voltage  
VMID Output Resistance  
Buffered Reference Voltage  
Microphone Bias  
VMID  
AVDD/2  
75  
V
k  
V
RVMID  
VREF  
AVDD/2  
Bias Voltage  
VMICBIAS  
MICBIAS = 01  
MICBIAS = 10  
0.75AVDD  
V
V
0.9AVDD 0.9AVDD 0.9AVDD  
–3%  
+3%  
MICBIAS = 11,  
AVDD = 2.5V  
1.2AVDD  
V
Bias Current Source  
Output Noise Voltage  
Digital Input / Output  
Input HIGH Level  
IMICBIAS  
Vn  
3
mA  
1K to 20kHz  
24  
nV/Hz  
VIH  
VIL  
0.7DBVDD  
0.9DBVDD  
V
V
V
V
Input LOW Level  
0.3DBVDD  
0.1DBVDD  
Output HIGH Level  
Output LOW Level  
VOH  
VOL  
IOH = 1mA  
IOL = -1mA  
TERMINOLOGY  
1. Signal-to-noise ratio (dB) – for the microphone preamplifiers, quoted SNR is the ratio of the rms voltages of the full-  
scale output at the L/RACOUT pins and the noise observed at these pins with no input signals. This figure indicates  
only the microphone preamplifier noise and does not account for additional noise that will be added by the PGAs and  
ADCs in obtaining the final digitised result. For the line inputs, quoted SNR is the ratio of the rms code ranges as  
measured at the ADC output for a full-scale output signal and the noise observed with no input. This figure combines  
the PGA and ADC noise contributions. (No Auto-zero or Auto-mute function is employed in achieving these results).  
2. Dynamic range (dB) - DR measures the ratio in the ADC output between the full-scale signal power and all power  
contributed by noise and spurious tones in the specified bandwidth. Normally THD+N is measured at 60dB below full  
scale (to reduce any distortion components to negligible levels) and the measurement is then corrected by adding the  
60dB to its magnitude. (e.g. THD+N @ -60dB= -32dB, DR= 60 + |-32| = 92dB).  
3. Total Harmonic Distortion and Noise (dB) - THD+N is a ratio of the rms values of (Noise + Distortion) and Signal.  
4. Channel Separation (dB) - Also known as Cross-Talk. This is a measure of the amount one channel is isolated from  
the other. Normally measured by sending a full scale signal down one channel and measuring how much of this signal  
appears at the output of the other channel.  
5. Hold Time is the length of time between a signal detected by the ALC as being too quiet and beginning to ramp up the  
gain. It does not apply to ramping down the gain when the signal is too loud, which happens without a delay.  
6. Ramp-up and Ramp-Down times are defined as the time it takes for the PGA to sweep across 90% of its gain range.  
7. All hold, ramp-up and ramp-down times scale proportionally with MCLK  
Notes:  
1. All performance measurements are done with a 20kHz low pass filter, and where noted an A-weight filter. Failure to  
use such a filter will result in higher THD+N and lower SNR and Dynamic Range readings than are found in the  
Electrical Characteristics. The low pass filter removes out of band noise; although this is not audible, it may affect  
dynamic specification values.  
2. VMID and VREF are each to be decoupled to a clean analogue ground with 10uF and 0.1uF capacitors placed as  
close to the device package as possible. Smaller capacitors may reduce performance. VREFP should be connected to  
VREF and VREFN should be connected to AGND using short PCB traces. It is not recommended to connect other  
components to VMID or VREF in case of noise injection to the internal references of the device.  
PD, Rev 4.4, January 2012  
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