TAS54x4C Hardware Design Guidelines
1.17 THD+N Versus Frequency
THD plus noise versus frequency is usually measured with ƒ
s
= 417K Hz at 45° phase difference and
crosstalk enhancement disabled (default). The following are two options to reducing THD measurements:
1. Lower the switching frequency. A lower switching frequency results in fewer samples taken of incorrect
data.
2. Switch to 180° phase difference. The amount of cross talk and feedback from other channels are
reduced.
These options can be incorporated individually or together. Therefore the best THD+N versus frequency
data would be to incorporate all of the options at once (for example: ƒ
s
= 357K HZ at 180° phase shift).
shows a graphical representation of these options.
V
(PVDD)
= 14.4 V
R
L
= 4
Ω
P
O
= 1 W
T
A
= 25°C
Figure 9. THD+N vs Frequency Improvements
19
SLOA196 – June 2014
TAS54x4C Design Guide
Copyright © 2014, Texas Instruments Incorporated
