TS4984FC View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'TS4984FC' PDF : 30 Pages View PDF
Application Information
TS4984FC
4.9 Application example: differential-input BTL power stereo
amplifier
The schematic in Figure 67 shows how to design the TS4984 to work in differential-input mode.
For this discussion, only the left-channel amplifier will be referred to.
Let:
R1R = R2L = R1, R2R = R2L = R2
CinR = CinL = Cin
The gain of the amplifier is:
GVdif=
2
R-----2--
R1
In order to reach the optimal performance of the differential function, R1 and R2 should be
matched at 1% maximum.
Figure 67. Differential input amplifier configuration
Neg. Input LEFT CinL
R1L
Pos. Input LEFT CinL
R1L
R2L
StandBy
Control
R2L
VCC
IN-L -
IN+L +
Cs
TS4984
VO-L
StandBy Bias
BypassL
-
AV = -1
+
VO+L
LEFT Speaker
8 Ohms
Pos. Input RIGHT CinR
R2R
R1R
Neg. Input RIGHT CinR
R1R
IN+R +
IN-R -
BypassR
Cb
VO-R
-
AV = -1
+
VO+R
RIGHT Speaker
8 Ohms
R2R
The value of the input capacitor Cin can be calculated with the following formula, using the -3dB
lower frequency required (where FL is the lower frequency required):
Cin
≈
---------1-----------
2πR1FL
(F)
24/30
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