Motorola MPC533 Reference Manual page 1111

V
DDKA
Figure K-6. Option B Power-Up Sequence With Keep-Alive Supply
The option B power-down sequence (excluding V
1. The V supply group can be fully powered-down prior to power-down of the
DDL
V supply group, with no adverse affects to the device.
DDH
For power-down, the low voltage supply should come down before the high voltage supply,
although with varying loads, the high voltage may actually get ahead.
Figure K-7 illustrates the power-down sequence if no keep-alive supply is required.
Figure K-8 illustrates the power-down sequence if a keep-alive supply is required.
V
DDH
V
DDL
V cannot lead V
DDH
Figure K-7. Option B Power-Down Sequence Without Keep-Alive Supply
MOTOROLA
PRELIMINARY—SUBJECT TO CHANGE WITHOUT NOTICE
V cannot lag V by more than 0.5 V
DDH DDL
V
DDH
0.5-V lag
by more than 0.5V
DDL
Appendix K. Electrical Characteristics
Power-Up/Down Sequencing
0.5-V lag
) is:
DDKA
≤ 5.25V
Ramp down rates may
differ with load.
V
DDH
V
DDL
K-17