TS4972IJT STMicroelectronics, TS4972IJT Datasheet - Page 23

• Manufacturer Part Number: TS4972IJT
• Description: 1.2W POWER AUDIO AMPLIFIER WITH STANDBY MODE ACTI
• Manufacturer: STMicroelectronics

In lower frequency we want 20 Hz (-3dB cut off
frequency). Then:
So, we could use for Cin a 1µF capacitor value
which gives 16Hz.
In Higher frequency we want 20kHz (-3dB cut off
frequency). The Gain Bandwidth Product of the
TS4972 is 2MHz typical and doesn't change when
the amplifier delivers power into the load.
The first amplifier has a gain of:
and the theoretical value of the -3dB cut-off higher
frequency is 2MHz/3 = 660kHz.
We can keep this value or limit the bandwidth by
adding a capacitor Cfeed, in parallel on Rfeed.
Then:
So, we could use for Cfeed a 220pF capacitor
value that gives 24kHz.
Now, we can calculate the value of Cb with the
formula b = 50k xCb >> in = (Rin+Rfeed)xCin
which permits to reduce the pop and click effects.
Then Cb >> 0.8µF.
We can choose for Cb a normalized value of 2.2µF
that gives good results in THD+N and PSRR.
In the following tables, you could find three
another examples with values required for the
demoboard.
Application n°1 : 20Hz to 20kHz bandwidth and
6dB gain BTL power amplifier.
Components :
R1
R4
R6
R7
Designator
C
C
FE E D
IN
=
=
----------------------------- - = 795nF
2
-------------------------------------- - = 265pF
2
Rfee d
----------------- = 3
RinF
R in
1
R
F E E D
22k / 0.125W
22k / 0.125W
Short Cicuit
100k / 0.125W
1
C L
F
C H
Part Type
Application n°2 : 20Hz to 20kHz bandwidth and
20dB gain BTL power amplifier.
Components :
R8
C5
C6
C7
C9
C10
C12
S1, S2, S6, S7
S8
P1
R1
R4
R6
R7
R8
C5
C6
C7
C9
C10
C12
S1, S2, S6, S7
S8
P1
Designator
Designator
Short Circuit
470nF
100µF
100nF
Short Circuit
Short Circuit
1µF
2mm insulated Plug
10.16mm pitch
3 pts connector 2.54mm
pitch
SMB Plug
110k / 0.125W
22k / 0.125W
Short Cicuit
100k / 0.125W
Short Cicuit
470nF
100µF
100nF
Short Circuit
Short Circuit
1µF
2mm insulated Plug
10.16mm pitch
3 pts connector 2.54mm
pitch
SMB Plug
Part Type
Part Type
TS4972
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