TS488 Datasheet, PDF (27/32 Pages) STMicroelectronics – Pop-free 120mW stereo headphone amplifier

TS488-TS489
Application information
With the values above, the result is F_CL=25Hz.
In this case, τ _in = R_in x C_in=6.6ms.
This value is sufficient with regard to the previous formula, thus we can state that the pop is
imperceptible.
Connecting the headphones
Note:
Generally headphones are connected using jack connectors. To prevent a pop in the
headphones when plugging in the jack, a pulldown resistor should be connected in parallel
with each headphone output. This allows the capacitors C_out to be charged even when the
headphones are not plugged in.
Pulldown resistors with a value of 1 kΩ are high enough to be a negligible load, and low
enough to charge the capacitors C_out in less than one second.
The pop&click reduction circuitry works properly only when both channels have the same
value for the external components C_in, C_out, R_load and R_pulldown.
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