LM3880, LM3880Q-1

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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.

0

0

0

0

2

4

6

8

4

8

12

16

6

12

18

24

8

16

24

32

10

20

30

40

12

24

36

48

14

28

42

56

16

32

48

64

18

36

54

72

20

40

60

80

22

44

66

88

24

48

72

96

26

52

78

104

28

56

84

112

30

60

90

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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Product Folder Links: LM3880 LM3880Q-1