WM8215

Production Data

w

PD, Rev 4.3, September 2012

12

Figure 7 Typical Power up Sequence where DVDD1 is Powered before AVDD

Figure 7 shows a typical power-up sequence where DVDD1 comes up first. First it is assumed that

DVDD1 is already up to specified operating voltage. When AVDD goes above the minimum threshold,

Vpora, there is enough voltage for the circuit to guarantee PORB is asserted low and the chip is held

in reset. In this condition, all writes to the control interface are ignored. When AVDD rises to

Vpora_on, PORB is released high and all registers are in their default state and writes to the control

interface may take place.

On power down, where DVDD1 falls first, PORB is asserted low whenever DVDD1 drops below the

minimum threshold Vpord_off.

SYMBOL

TYP

UNIT

0.6

V

1.2

V

0.6

V

0.7

V

0.6

V

Table 1 Typical POR Operation (typical values, not tested)

Note: It is recommended that every time power is cycled to the WM8215 a software reset is written to

the software register to ensure that the contents of the control registers are at their default values

before carrying out any other register writes.