LM3880_07 Datasheet, PDF (1/12 Pages) –

March 2007
LM3880
Power Sequencer
General Description
The LM3880 Power Sequencer offers the easiest method to
control power up and power down of multiple power supplies
(switchers or linear regulators). By staggering the startup se-
quence, it is possible to avoid latch conditions or large in-rush
currents that can affect the reliability of the system.
Available in a SOT23-6 package, the Power Sequencer con-
tains a precision enable pin and three open drain output flags.
Upon enabling the LM3880 the three output flags will sequen-
tially release, after individual time delays, permitting the con-
nected power supplies to startup. The output flags will follow
a reverse sequence during power down to avoid latch condi-
tions.
Standard timing option of 30ms is available.
EPROM capability allows every delay and sequence to be
fully adjustable. Contact National Semiconductor if a non-
standard configuration is required.
Features
■ ^{Easiest method to sequence rails}
■ ^{Power up and power down control}
■ ^{Input voltage range of 2.7V to 5.5V}
■ ^{Small footprint SOT23-6}
■ ^{Low quiescent current of 25 µA}
■ ^{Standard timing options available}
■ ^{Customization of timing and sequence available through}
factory programmability
Applications
■ ^{Multiple supply sequencing}
■ ^{Microprocessor / Microcontroller sequencing}
■ ^{FPGA sequencing}
Typical Application Circuit
20192601
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