Rainbow Electronics AT73C246 - Manual (Page 26)

26
11050A–PMAAC–07-Apr-10
AT73C246
11.2 PMU Startup and Shutdown State Diagram
Figure 11-2. AT73C246 Start-up and Shutdown State Diagram
The start-up of the AT73C246 follows the flow diagram of Figure 11-2 and aims at placing the
power manager in the POWERDOWN state.
When V
INSYS
rises above 2V:
• An internal V
INSYS
monitor starts and holds the internal PMU_RSTN and AUDIO_RSTN
signals to 0, thus forcing a complete reset of AT73C246. The PMU digital core supply voltage
Start : V
INSYS
Monitor &
V
DDC
= 1.8V.
PMU_RSTN = 0
AUDIO_RSTN = 0
V
INSYS
< 2.7V
or
V
DDC
_KO
Vin > 2V
V INSYS > 2.7V &
V
DDC
_OK
PMU_RSTN = 1
AUDIO_RSTN = 1
1
READ
CONFIG
V
BACKUP
< 1.8V
RTC_RSTN = 0
1
START
LDO5
(BACKUP)
V
BACKUP
> 1.8V
RTC_RSTN = 1
POWER
DOWN
V
BACKUP
> 1.8V
START
LDO5
(BACKUP)
V
BACKUP
> 1.8V
V
INSYS
< 2.7V
OFF
LDO5
(BACKUP)
1