Cirrus Logic AN331 - Manual (Page 4)

AN331
4
3.1 The Subtraction Approach
The schematic in Figure 3 is a suggested buffer implementation for the analog inversion with digital subtraction tech-
nique, e
o
= (A / 2) - (B / 2). The analog inversion can be easily implemented in the connections to the differential A/D
inputs where the AIN+ connection is routed to the AINR- and the AINL+, and the AIN- connection is routed to the
AINR+ and the AINL-, as shown in Figure 3. This cross connection of the analog inputs results in the inversion of
the Right channel input relative to the Left channel.
Figure 3. CS5381 Recommended Buffer Implementation for Channel Inversion
VQ
10 k Ω
10 k Ω
+
634
Ω
634
Ω
91 Ω
91 Ω +
-
-
2700 pF
470 pF
470 pF
COG
COG
10 uF
10 uF
AINL+
AINL-
COG
+
634 Ω
634 Ω
91 Ω
91 Ω
+
-
-
2700 pF
470 pF
470 pF
COG
COG
AINR-
AINR+
COG
AIN-
100 k Ω
AIN+
100 k Ω