Pre-Production
WM8904
Differential Stereo Record from Analogue Microphones - IN1L+IN2L / IN1R+IN2R pins to ADC output
Test conditions:
L_MODE = R_MODE = 10b (Differential mic)
LIN_VOL = RIN_VOL = 00111b (+30dB)
Total signal path gain = +30dB
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
0.032
-30
MAX
UNIT
Vrms
dBV
Differential Mic Input Full Scale
Signal Level
IN1L-IN2L / IN1R-IN2R (for ADC
0dBFS output)
0.089
Vpk-pk
Input Resistance
Rin
Cin
100
120
10
k
pF
dB
Input Capacitance
Signal to Noise Ratio
SNR
A-weighted
68
ADC_OSR128 = 0
ADC_128_OSR_TST
_MODE = 1
ADC_BIASx1P5 = 1
A-weighted
67
77
Best performance
mode::
ADC_OSR128 = 1
ADC_128_OSR_TST
_MODE = 0
ADC_BIASx1P5 = 0
-31dBV input
Total Harmonic Distortion + Noise
Common Mode Rejection Ratio
Channel Separation
THD+N
CMRR
-75
60
-65
dB
dB
1kHz, 100mVpk-pk
1kHz signal, -31dBV
10kHz signal, -31dBV
1kHz signal, -31dBV
217Hz, 100mVpk-pk
1kHz, 100mV pk-pk
85
dB
dB
dB
80
Channel Level Matching
PSRR (Referred to Input)
+/-1
50
PSRR
50
PGA and Microphone Boost
PARAMETER
TEST CONDITIONS
MIN
TYP
-1.55
+12
MAX
UNIT
Minimum PGA gain setting
L_MODE/R_MODE= 00b or 01b
L_MODE/R_MODE= 10b
dB
Maximum PGA gain setting
L_MODE/R_MODE= 00b or 01b
L_MODE/R_MODE= 10b
+28.28
+30
dB
Single-ended to differential
conversion gain
L_MODE/R_MODE= 00b
+6
dB
dB
PGA gain accuracy
L_MODE/R_MODE= 00b
Gain -1.5 to +6.7dB
-1
-1.5
-1
+1
+1.5
+1
L_MODE/R_MODE= 00b
Gain +7.5 to +28.3dB
L_MODE/R_MODE= 1X
Gain +12 to +24dB
L_MODE/R_MODE= 1X
Gain +27 to +30dB
-1.5
+1.5
Mute attenuation
all modes of operation
L_MODE/R_MODE= 00b or 01b
100
30
dB
Equivalent input noise
µVrms
nV/√Hz
214
PP, Rev 3.3, September 2012
15
w
WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
