LM3880MF-1AENOPB Datasheet, PDF (11/22 Pages) Texas Instruments – LM3880/LM3880Q-1 Power Sequencer

LM3880, LM3880Q-1
www.ti.com
SNVS451I – AUGUST 2006 – REVISED MARCH 2013
CUSTOM SEQUENCER
The LM3880 Power Sequencer is based on a CMOS process utilizing an EPROM that has the capability to be
custom programmed at the factory. Approximately 500,000,000 different options are available allowing even the
most complex system to be simply sequenced. Because of the vast options that are possible, customization is
limited to orders of a certain quantity. Please contact Texas Instruments for more information.
The variables that can be programmed include the six delay timers and the reverse sequence order. For the
timers, each can be individually selected from one of the timer selector columns in the table shown below.
However, all six time delays must be from the same column.
Timer Options 1⁽¹⁾
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
Timer Options 2⁽¹⁾
0
4
8
12
16
20
24
28
32
36
40
44
48
52
56
60
Timer Options 3⁽¹⁾
0
6
12
18
24
30
36
42
48
54
60
66
72
78
84
90
Timer Options 4⁽¹⁾
0
8
16
24
32
40
48
56
64
72
80
88
96
104
112
120
(1) All times listed are in milliseconds
The sequencing order for power up is always controlled by layout. The flag number translates directly into the
sequence order during power up (ie FLAG1 will always be first). However, for some systems a different power
down order could be required. To allow flexibility for this aspect in a design, the Power Sequencer incorporates
six different options for controlling the power down sequence. These options can be seen in the timing diagrams
on the next page. This ability can be programmed in addition to the custom timers.
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