Cirrus Logic CS53L21 - Manual (Page 24)

24 DS700PP1
CS53L21
The MICBIAS series resistor must be selected based on the requirements of the particular microphone
used. The MICBIAS output pin is selected using the MICBIAS_SEL bit.
Software
Controls:
“Interface Control (Address 04h)” on page 43 , “MIC Control (Address 05h)” on page 44 .
fc
1
2 π 50 kΩ ( ) 1 μF ( )
----------------------------------------------- 3.18 Hz = =
MICIN1
MICIN2
Σ
+
+
MICBIAS
18
17
20
//
//
Figure 8. MIC Input Mix w/Common Mode Rejection
Full-Scale Differential Input Level (MICMIX=1)
= (AINxA - AINxB) = 3.6 V
PP
= 1.27 V
RMS
AINxA
AINxB
2.15 V
1.25 V
0.35 V
2.5 V
2.15 V
1.25 V
0.35 V
VA
Figure 9. Differential Input