TS4974_07 STMICROELECTRONICS [STMicroelectronics], TS4974_07 Datasheet - Page 19

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

TS4974
4.4
4.5
4.6
Note:
Decoupling of the circuit
Two capacitors are needed to correctly bypass the TS4974. A power supply bypass
capacitor C
C
an indirect influence on power supply disturbances. With a value for C
expect similar THD+N performance to that shown in the datasheet.
In the high frequency region, if C
disturbances on the power supply rail are less filtered.
On the other hand, if C
more filtered.
C
result of PSRR (with input grounded and in the lower frequency region).
Wake-up time (t
When the standby is released to put the device ON, the bypass capacitor C
immediately. As C
properly until the C
time or t
with C
up time, the gain is released and set to its nominal value.
If C
Figure 40. Startup time vs. bypass capacitor
Shutdown time
When the standby command is set, the time required to put the two output stages in high
impedance and the internal circuitry in shutdown mode is a few microseconds.
In shutdown mode, the Bypass pin and Vin+, Vin- pins are short-circuited to ground by
internal switches. This allows a quick discharge of C
S
b
has an influence on THD+N at lower frequencies, but its function is critical to the final
has particular influence on the THD+N in the high frequency region (above 7 kHz) and
b
has a value other than 1 µF, refer to
b
=1 µF. During the wake-up phase, the TS4974 gain is close to zero. After the wake-
WU
S
and is specified in the tables in
and a bias voltage bypass capacitor C
b
b
is directly linked to the bias of the amplifier, the bias will not work
voltage is correct. The time to reach this voltage is called the wake-up
S
WU
is higher than 1 µF, the disturbances on the power supply rail are
15
10
5
0
)
Tamb=25
0,4
S
is lower than 1 µF, it increases the THD+N, and
°
C
Bypass Capacitor Cb (
0,8
Figure 40
Vcc=3.3V
Section 3: Electrical characteristics on page
Vcc=5V
1,2
b
to establish the wake-up time.
b
.
and C
Vcc=2.6V
μ
1,6
F)
in
capacitors.
2,0
Application information
S
of 1 µF, you can
b
is not charged
19/25
5,