TS4961T STMicroelectronics, TS4961T Datasheet - Page 36

• Manufacturer Part Number: TS4961T
• Description: Mono Class D Audio Power Amplifier With Dedicated Analog Switch
• Manufacturer: STMicroelectronics

Application component information
4.1
36/49
Common mode feedback loop limitations
The common mode feedback loop allows the output DC bias voltage to be averaged at
V
However, because of the V
for audio amplifier section on page
role within a defined range. This range depends upon the values of V
obtain a good estimation of the V
on R
with
and the result of the calculation must be in the range:
Due to the +/-9% tolerance on the 150 kΩ resistor, it is also important to check V
conditions:
If the result of the V
must be used (with V
For example:
With V
than 3 V - 0.8 V = 2.2 V. With 136.5 kΩ we find 1.97 V, and with 163.5 kΩ we have 2.02 V.
Therefore, no input coupling capacitors are required.
CC
/2 for any DC common mode bias input voltage.
in
):
CC
= 3 V, R
in
V
---------------------------------------------------------------------------------- - V
icm
= 150 kΩ and V
CC
CC
×
calculation is not in the previous range, input coupling capacitors
2
from 2.4 V to 2.5 V, input coupling capacitors are mandatory).
R
×
in
icm
(
R
+
in
2
limitation in the input stage (see
V
+
×
icm
136.5kΩ
icm
V
IC
3), the common mode feedback loop can only fulfill its
=
IC
value, the following formula can be used (no tolerance
×
V
----------------------------------------------------------------------------- -
= 2.5 V, we typically find V
CC
136.5kΩ
0.5V V
)
V
×
IC
2
R
×
≤
=
in
(
R
≤
+
icm
In
---------------------
in
2
+
icm
×
+
≤
2
+
V
150kΩ
In
V
≤
CC
IC
-
V
---------------------------------------------------------------------------------- -
×
–
CC
(V)
0.8V
150kΩ
)
×
2
R
×
Table 2: Operating conditions
in
(
icm
R
+
in
2
= 2 V and this is lower
+
×
(V)
CC
163.5kΩ
V
IC
and R
×
163.5kΩ
)
in
icm
(Av). To
TS4961T
in these