TS4998 STMicroelectronics, TS4998 Datasheet - Page 28

• Manufacturer Part Number: TS4998
• Description: 2 X 1w Differential Input Stereo Audio Amplifier
• Manufacturer: STMicroelectronics

Application information
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Notes on PSRR measurement
What is the PSRR?
The PSRR is the power supply rejection ratio. The PSRR of a device is the ratio between a
power supply disturbance and the result on the output. In other words, the PSRR is the
ability of a device to minimize the impact of power supply disturbance to the output.
How is the PSRR measured?
The PSRR is measured as shown in
Figure 68. PSRR measurement
Principles of operation
●
●
●
The PSRR value for each frequency is calculated as:
RMS is an rms selective measurement.
The DC voltage supply (V
The AC sinusoidal ripple voltage (V
No bypass capacitor C
Cin1
4.7uF
Cin2
4.7uF
Cin3
4.7uF
Cin4
4.7uF
Rin1
Rin2
Rin3
Rin4
S
PSRR
1uF
Cb
is used
14
1
2
4
3
CC
U1
TS4998
LI N-
LI N+
RIN-
RIN+
Bypass
) is fixed
=
Figure
RIGHT
LEFT
20
GND
ripple
×
BIAS
Log
68.
GND
) is fixed
--------------------------------- -
RMS
RMS
(
STBY
(
Vripple
Output
-
+
-
+
TS4998 - QFN16
)
)
Vcc
(
dB
LOUT-
LOUT+
ROUT-
ROUT+
)
12
11
9
10
RL
8Ohms
RL
8Ohms
Vripple
Vcc
TS4998