WM8903LGEFK/V Wolfson Microelectronics, WM8903LGEFK/V Datasheet - Page 110

• Manufacturer Part Number: WM8903LGEFK/V
• Description: Audio CODECs ULTRA LOW PWR HI FI CODEC
• Manufacturer: Wolfson Microelectronics

Specifications of WM8903LGEFK/V

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

WM8903
Figure 63 Typical Power up Sequence where DCVDD is Powered before AVDD
w
POWER-UP TIMING - DCVDD POWERED BEFORE AVDD
Figure 63 shows the power-up sequence where DCVDD is powered up before AVDD. It is assumed
that DCVDD is at the specified operating voltage before AVDD rises to the minimum threshold, V
At this point, 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 V
to the control interface may take place.
On power down, where DCVDD falls first, PORB is asserted low whenever DCVDD drops below the
minimum threshold V
POWER-UP / POWER-DOWN CHARACTERISTICS
The threshold voltages and timing characteristics for power-up and power-down are listed in Table
73.
Table 73 Typical POR Operation (typical values, not tested)
Notes:
1.
2.
3.
SYMBOL
V
V
V
V
If AVDD and DCVDD suffer a brown-out (i.e. drop below the minimum recommended operating
level but do not go below V
operation when the voltage is back to the recommended level again.
The chip enters reset at power down when AVDD or DCVDD falls below V
may be important if the supply is turned on and off frequently by a power management system.
The minimum t
specification is guaranteed by design rather than test.
V
pora_off
pord_off
pora_on
pord_on
T
pora
por
MIN
por
pord_off
pora_on
period is maintained even if DCVDD and AVDD have zero rise time. This
1.15
1.12
0.57
0.56
10.6
.
TYP
0.5
, PORB is released high, all registers are in their default state and writes
pora_off
MAX
or V
pord_off
UNIT
μs
V
V
V
V
V
) then the chip does not reset and resumes normal
PP, Rev 3.1, August 2009
pora_off
or V
Pre-Production
pord_off
. This
110
pora
.