Analog Devices ADAV4601 System Design Document page 22

Vref Vref
(1.5V) (1.5V)
This register write powers down the Vref buffer. The reference voltage Vref has now been powered down to 0V
which means that the input to every amplifier is already at 0V. Therefore there is no longer any need for the Vref
buffer to be powered up.
This register write enables Vref which effectively connects the output of the Vref buffer to ground and also clamps
the headphone outputs to ground. It is recommended to wait for 1 second after performing this write to ensure
that all residual charge is gone from the Vref capacitor.
This write tri-states the headphone outputs which sets the outputs of the headphones to high-impedance.
This write disables the PWM channels. It is recommended to wait for 2 seconds after this write before performing an
2
additional I C write.
These register writes power down the headphone amplifier, headphones DACs and all the Auxiliary DACs as well as
putting all DACs in low power mode.
This register write powers down the rest of the device. This disables all the digital section on the ADAV46xx as well
as disabling the processor and the PLL.
ADAV4601 System Design Document
Rev.1 August 2009
0V 0V
Figure 13: Vref Discharger Circuit
34 0005 866F
34 008D 02A1
34 000B 0000
34 000A 0F81
34 0006 0200
34 0005 0000
34 0000 0000
Analog Devices
Vref discharger circuit Vref discharger circuit
Discharging Vref Discharging Vref
Instantaneously Instantaneously
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