CM6571 Datasheet, PDF (62/63 Pages) C-Media Electronics – USB 2.0 full speed-compliant

CM6571
USB Audio Sound Chip
10.5.4 DSP audio quality
Test Conditions: AVDD = 2.8V, DVDD (V_DD)= 1.8V DGND =0V, Fs= 16kHz, PGA Gain= 0dB, TA=+25^oC, output
loading=10K ohms, mic-in coupling capacitor= 220nF, w/ 8kHz Filter
Item
Min.
Typ.
ADC Performance
Resolution
-
16
Sample rate
-
16K
THD + N (@1kHz)
-
-60
SNR (@1kHz)
85
90
Dynamic range (@1kHz)
85
90
Frequency response (-3dB/-9dB)
60
-
Passband ripple
-
±0.25
Single-ended full-scale input voltage
-
1.41¹
differential full-scale input voltage
-
2.82¹
Power supply rejection ratio (217Hz)
85
Microphone/Aux Input
Mic-in PGA gain range
0
+20 (default)
Aux-in PGA gain range
-12
+8 (default)
ADC PGA gain step
-
1
Mic input impedance
-
15K
Aux input impedance
60K
Microphone bias voltage
-
1.9
DAC Performance (10K Ohm Line Loading)
Resolution
-
16
Sample rate
16K
THD + N (@1kHz)
-
-67.5
SNR (@1kHz)
-
90
Dynamic range (@1kHz)
-
85.5
Frequency response (-3dB/-3dB)
20
-
Passband ripple
-
+-0.1
Single-ended full-scale output voltage
-
1.41
Differential full-scale output voltage
-
2.82
Power supply rejection ratio (217Hz)
80
DAC/Analog Output Gain
DAC PGA gain range
-31
-17 (default)
DAC PGA gain step
-
1
Max.
-
-
-
-
-
6.8K
-
-
-
+31
+19
-
-
-
-
-
-
-
6.8K
-
-
-
0
-
Unit
bit
Hz
dBFS
dBFS
dBFS
Hz
dBFS
Vp-p
Vp-p
dB
dB
dB
dB/Step
Ω
Ω
V
Bits
Hz
dBFS
dBFS
dBFS
Hz
dBFS
Vp-p
Vp-p
dB
dB
dB/Step
Note: Although the full-scale input voltage can be as high as 1.55Vp-p, the recommended max input voltage is below
1.41Vp-p (500mVrms) for single-ended input and 2.82Vp-p (1.0Vrms) for differential input to reserve the best signal
linearity.
Revised: Nov. 2012
Page 62 / 63
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