Datasheet

TS4990 Application information
Doc ID 9309 Rev 13 23/33
4.9 Application example: differential input, BTL power amplifier
The schematics in Figure 64 show how to configure the TS4990 to work in differential input
mode. The gain of the amplifier is:
In order to reach the best performance of the differential function, R
1
and R
2
should be
matched at 1% max.
Figure 64. Differential input amplifier configuration
The input capacitor C
in
can be calculated by the following formula using the -3 dB lower
frequency required. (F
L
is the lower frequency required).
Note: This formula is true only if:
is 5 times lower than F
L
.
G
VDIFF
2
R
2
R
1
------ -
=
R2
R1
Neg. Input
Vcc
Cin
+
Cs
+
Cb
Standby
Control
Speaker
8Ohms
Bias
AV = -1
Vin-
Vin+
Bypass
Standby
VCC
GND
Vout 1
Vout 2
+
-
+
-
TS4990
R1
Pos. Inpu t
Cin
R2
C
in
1
2πR
1
F
L
---------------------
(F)≈
F
CB
1
2π R
1
R
2
+()C
B
----------------------------------------
(Hz)=