Datasheet

TS4990 Application information
Doc ID 9309 Rev 13 21/33
4.6 Wake-up time (t
WU
)
When the standby is released to put the device ON, the bypass capacitor C
b
is not charged
immediately. Because C
b
is directly linked to the bias of the amplifier, the bias will not work
properly until the C
b
voltage is correct. The time to reach this voltage is called wake-up time
or t
WU
and specified in the electrical characteristics tables with C
b
=1µF.
If C
b
has a value other than 1 µF, refer to the graph in Figure 61 to establish the wake-up
time.
Figure 61. Typical wake-up time vs. C
b
Due to process tolerances, the maximum value of wake-up time is shown in Figure 62.
Figure 62. Maximum wake-up time vs. C
b
Note: The bypass capacitor C
b
also has a typical tolerance of +/-20%. To calculate the wake-up
time with this tolerance, refer to the graph above (considering for example for C
b
=1 µF in the
range of 0.8 µF
≤ C
b
≤ 1.2 µF).
4.7 Standby time
When the standby command is set, the time required to put the two output stages in high
impedance and the internal circuitry in standby mode is a few microseconds. In standby
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0
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4.7
0.1
Tamb=25°C
Vcc=2.6V
Vcc=3.3V
Vcc=5V
Startup Time (ms)
Bypass Capacitor Cb ( F)
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0
100
200
300
400
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600
Tamb=25 ° C
4.70.1
Vcc=5V
Vcc=3.3V
Vcc=2.6V
Max. Startup Time (ms)
Bypass Capacitor Cb ( F)