adm1069ast-reel Analog Devices, Inc., adm1069ast-reel Datasheet - Page 19

• Manufacturer Part Number: adm1069ast-reel
• Description: Super Sequencer With Margining Control
• Manufacturer: Analog Devices, Inc.

SEQUENCING ENGINE APPLICATION EXAMPLE
The application in this section demonstrates the operation of
the sequencing engine (SE). Figure 26 shows how the simple
building block of a single SE state can be used to build a power-
up sequence for a three-supply system.
Table 8 lists the PDO outputs for each state in the same SE
implementation. In this system, the presence of a good 5 V
supply on VP1 and the VX1 pin held low are the triggers required
for a power-up sequence to start. The sequence next intends to turn
on the 3.3 V supply, and then the 2.5 V supply (assuming successful
turn-on of the 3.3 V supply). Once all three supplies are good,
the PWRGD state is entered, where the SE remains until a fault
occurs on one of the three supplies, or until it is instructed to go
through a power-down sequence by VX1 going high.
Faults are dealt with throughout the power-up sequence on a
case-by-case basis. The following three sections (Sequence
Detector, Monitoring Fault Detector, and Timeout Detector)
describe the individual blocks and use the sample application in
Figure 26 to demonstrate the state machine’s actions.
Table 8. PDO Outputs for Each State
PDO Outputs
PDO1 = 3V3ON
PDO2 = 2V5ON
PDO3 = FAULT
IDLE1
0
0
0
IDLE2
0
0
0
EN3V3
1
0
0
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EN2V5
1
1
0
DIS3V3
0
1
1
VP1 = 0
MONITOR FAULT
FSEL2
VP2) = 0
(VP1 + VP2 + VP3) = 0
STATES
Figure 26. Sample Application Flow Diagram
VP2 = 0
(VP1 +
DIS2V5
1
0
1
(VP1 + VP2) = 0
FSEL1
VP3 = 0
VP1 = 0
SEQUENCE
PWRGD
1
1
0
PWRGD
STATES
EN3V3
EN2V5
IDLE1
IDLE2
VX1 = 0
VP1 = 1
VX1 = 1
VP3 = 1
VP2 = 1
VP2 = 0
10ms
20ms
DIS3V3
DIS2V5
FSEL1
1
1
1
TIMEOUT
STATES
VX1 = 1
VX1 = 1
ADM1069
FSEL2
1
1
1