YDA131

9

●

Pop noise reduction function

This IC includes pop noise reduction function that works when turning on and shutting off the power supply, and

controlling the mute or sleep functions.

・

When turn on the power supply

This IC is in mute state immediately after turning on the power supply.

The starting process is performed at the power on (sleep cancellation), and after the internal operation stabilizes, the mute

state is cancelled. This operation minimizes the generation of pop noise at turning on the power supply.

These values must be same for both channels.

VREFL and VREFR terminals must be discharged sufficiently before turning on the power supply again. If you turn on

the power supply again without discharged sufficiently these capacitors, this function does not operate effectively, and

there is a possibility that pop noise generates.

・

Starting time

VREFL and VREFR terminals) when the power supply is turned on or is turned on again. This period varies in relation to

The table of starting time is as follows:

Table: Starting time

CR1capacitor(µF)

Starting time (sec)

2

0.13

10

0.33

30

0.85

50

1.40

・

When shutting off the power supply

This IC performs muting processing internally when the power supply voltage has changed by more than10% in a very

short period or when the power supply voltage is reduced below 3.0V to reduce the pop noise when the IC is shut off.

To make this function operate efficiently, it is necessary to fall the power voltage quickly when shutting off the power

supply.

When the power is supplied to the IC through a voltage regulator and a large capacitance is connected after the regulator,

such as the case shown in "Figure 5: Power supply fall acceleration circuit example", the voltage of VDD can be reduced

quicker if a diode is connected to it.