TS4974_07 STMICROELECTRONICS [STMicroelectronics], TS4974_07 Datasheet - Page 16

• Manufacturer Part Number: TS4974_07
• Description: 1W differential audio power amplifier with up/down digital volume control pins
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

Application information
4
4.1
4.2
Note:
16/25
Application information
Differential configuration principle
The TS4974 is a monolithic full-differential input/ output power amplifier with a digital volume
control. It has an internal gain range of -33 dB up to +12 dB, by steps of 3dB (see
Section 4.9: Volume setting on page
immunity and PSRR.
The advantages of a full-differential amplifier are:
●
●
●
●
In theory, the filtering of the internal bias by an external bypass capacitor is not necessary.
But, to reach maximum performance in all tolerance situations, it is better to keep this
option.
Low frequency response
The input coupling capacitors block the DC part of the input signal at the amplifier inputs.
Input capacitors C
cut-off frequency.
Differential input impedance of 60 k
value.
From
-3 dB.
Figure 39. -3dB lower cut-off frequency vs. input capacitance
Very high PSRR (power supply rejection ratio).
High common mode noise rejection.
Virtually zero pop without additional circuitry, giving a faster start-up time compared to
conventional single-ended input amplifiers.
Easier interfacing with differential output audio DAC.
Figure 39
you can easily establish the C
in
and input impedance Z
100
10
0.1
Typical Input
Impedance
F
Ω
CL
20), which offers better performance in terms of noise
Maximum Input
Impedance
is a typical value, and there is tolerance around this
=
Input Capacitor Cin (
2
×
π
in
×
R
1
forms a first-order, high pass filter with -3 dB
in
in
×
value required for a cut-off frequency of
C
in
(
Hz
)
μ
0.5
Minimum Input
Impedance
F)
All gain setting
Tamb=25
°
C
1
TS4974