Power-Down Sequence; Brown-Out Management - STMicroelectronics SPC572L series Reference Manual

RM0400
POWERUP
6.0 V
3.0 V
UPPER THRESHOLD
2.7 V
The device needs to fulfill all conditions described on
recover.
9.6.2

Power-down sequence

When the threshold of the higher-range LVDs configured to generate a destructive reset is
crossed but neither LVD098 nor LVD270 threshold are crossed, the device enters PHASE0.
1. The power-down sequence initiates when the LVD098 or LVD270 threshold is crossed
2. The device enters the POWERUP state and the internal power-on signal ipp_por_en_b
is asserted.
3. On ipp_por_en_b assertion, all analog modules reach their safe state.
4. Device supplies may then proceed to drop down to ground either through device
leakage or external pull-down. During power-down, all supplies should comply with
supply constraints.
9.6.3

Brown-out management

During brown-out, the device re-enters the POWERUP phase as soon as the threshold of
either LVD098 or LVD270 is crossed. The internal power-on signal ipp_por_en_b is
asserted.
Note: The device will correctly start independently from any residual voltage.
The device remains in the POWERUP state until the voltage rises above the LVD270
threshold. It then passes to a RESET state defined by Voltage monitor or external PORST
pin, or ACTIVE state when all have been released.
Figure 41. Threshold variation during power-up sequence
P0 P1 P2
100 mV hysteresis
LOWER THRESHOLD
DocID027809 Rev 4
Power management
P3
5.5 V
4.5 V
3.9 V
3.6 V
Fully functional
Functional Margin
Reliability restriction
Out of spec
Section 9.6.1: Power-up sequence to
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