WM8976GEFL/V Wolfson Microelectronics, WM8976GEFL/V Datasheet - Page 19

• Manufacturer Part Number: WM8976GEFL/V
• Description: Audio CODECs Mono ADC Stereo DAC with Spkr
• Manufacturer: Wolfson Microelectronics

Specifications of WM8976GEFL/V

• Mounting Style: SMD/SMT
• Package / Case: QFN-32
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Production Data
Table 3 Typical POR operation (typical values, not tested)
Notes:
If AVDD and DVDD suffer a brown-out (i.e. drop below the minimum recommended operating level but do not go below V
V
The chip will enter reset at power down when AVDD or DVDD falls below V
turned on and off frequently by a power management system.
The minimum t
rather than test.
w
pord_off
) then the chip will not reset and will resume normal operation when the voltage is back to the recommended level again.
por
period is maintained even if DVDD and AVDD have zero rise time. This specification is guaranteed by design
Figure 9 Typical Power up Sequence where DVDD is Powered before AVDD
Figure 9 shows a typical power-up sequence where DVDD comes up first. First it is assumed that
DVDD is already up to specified operating voltage. When AVDD goes above the minimum threshold,
V
reset. In this condition, all writes to the control interface are ignored. When AVDD rises to V
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 DVDD falls first, PORB is asserted low whenever DVDD drops below the
minimum threshold V
pora
SYMBOL
V
V
V
V
V
, there is enough voltage for the circuit to guarantee PORB is asserted low and the chip is held in
pora_on
pora_off
pord_on
pord_off
pora
MIN
0.4
0.9
0.4
0.5
0.4
pord_off
TYP
0.6
1.2
0.6
0.7
0.6
.
MAX
0.8
1.6
0.8
0.9
0.8
UNIT
V
V
V
V
V
pora_off
or V
pord_off
. This may be important if the supply is
PD Rev 4.4 July 2009
WM8976
pora_off
pora_on
19
or
,