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TS4990

Application information

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, R1 and R2 should be

matched at 1% max.

Figure 64. Differential input amplifier configuration

The input capacitor Cin can be calculated by the following formula using the -3 dB lower

frequency required. (FL is the lower frequency required).

Note:

This formula is true only if:

is 5 times lower than FL.

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

Vout 1

Vout 2

+

-

+

-

TS4990

R1

Pos. Input

Cin

R2

C

in

1

2

R

1FL

---------------------

(F)



F

CB

1

2

 R

1

R

2

+

C

B

----------------------------------------

(Hz)

=