Philips TDA8950 Fig 5. Timing on mode selection input

TDA8950_1 © NXP B.V. 2008. All rights reserved.
Preliminary data sheet Rev. 01 — 9 September 2008 7 of 39
NXP Semiconductors TDA8950
2× 150 W class-D power amplifier
In order to fully charge the coupling capacitors at the inputs, the amplifier will remain
automatically in the Mute mode before switching to the Operating mode. A complete
overview of the start-up timing is given in Figure 5.
(1) First 1⁄4 pulse down.
Upper diagram: When switching from standby to mute, there is a delay of approximately 100 ms
before the output starts switching. The audio signal is available after VMODE has been set to
operating, but not earlier than 150 ms after switching to mute. For pop noise-free start-up it is
recommended that the time constant applied to pin MODE is at least 350 ms for the transition
between mute and operating.
Lower diagram: When switching directly from standby to operating, there is a first delay of 100 ms
before the outputs starts switching. The audio signal is available after a second delay of 50 ms. For
pop noise-free start-up it is recommended that the time constant applied to pin MODE is at least
500 ms for the transition between standby and operating.
Fig 5. Timing on mode selection input
2.2 V < VMODE < 3 V
audio output
operating
standby
mute
50 %
duty cycle
> 4.2 V
0 V (SGND) time
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VMODE
100 ms
50 ms
modulated PWM
> 350 ms
2.2 V < VMODE < 3 V
audio output
operating
standby
mute
50 %
duty cycle
> 4.2 V
0 V (SGND) time
VMODE
100 ms
50 ms
modulated PWM
> 350 ms
(1)
(1)