WM8803CDTSLASHV datasheet(9/45 Pages) WOLFSON

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WM8803

PP Rev 1.1 September 2003

DEVICE DESCRIPTION

SYSTEM RESET (

_____

PD)

The system operates normally when PD is set to high level after applying a supply voltage of

2.7V(3.0V) or higher. Following power ON, the system is reset by setting PD to low level again.

System reset is enabled by setting PDB at power on.

If a crystal oscillator is used, after setting PD low level and then high level, at least 10ms should be

allowed before starting normal operation until the oscillator element is stable.

VDD

System reset

System operation

2.7V

2.0V

t >

µµµµ200 sec

Figure 3 PD Pin Levels at Power On

LOW POWER MODES

The WM8803 not only supports a total system power down mode controlled with the PD pin but also

provides low-power modes in which only certain functions operate. These low power modes are

controlled by PDOWN[1:0].

The “power down” mode controlled by the PD pin applies to all circuits in the WM8803. All clocks

are stopped and the registers are initialized.

The XIN and XOUT pins continue to operate in the PDOWN[1:0] controlled low power mode, which

stops all circuits other than the oscillator amplifier. The XOUT signal can be used as the master clock

for a DSP or other circuits.

The CLKOUT, BCLK, LRCLK, SDATO, SDIN, XIN and XOUT pins continue to operate in the

PDOWN[1:0] controlled low power mode, which stops all circuits other than the oscillator amplifier

and the divider circuit . This mode can be used to minimize power consumption during analogue data

reception.

In a low power mode set with the PDOWN[1:0] and with the oscillator amplifier stopped by setting

AMPOPR, it will not be possible for the WM8803 to provide a clock output. The AMPOPR overrides

all other oscillator settings. Note that the PLLOPR setting is invalid and the PLL circuit will be

stopped.

When a low power mode is set up with the PDOWN[1:0], it is possible to write to the micro-controller

registers. However, all the sub-code Q and channel status data will read out as zeros.

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