National Semiconductor LM3881 Power Sequencer Data Sheet
Summary
The LM3881 Power Sequencer is an integrated circuit designed to precisely manage the synchronized power up and down sequencing of multiple supply rails for complex systems. This device ensures reliable system startup by staggering power supplies, preventing damaging conditions like latch-up or large in-rush currents across various applications, including microprocessors, microcontrollers, and FPGAs. The provided manual is a comprehensive technical resource detailing the chip's operation, covering detailed electrical characteristics, connection diagrams, timing adjustments, and crucial application guidelines needed for reliable power sequencing implementation.
Page 1 Text Content
February 6, 2008
LM3881 Power Sequencer General Description Features The LM3881 Power Sequencer offers the easiest method to Easiest method to sequence rails control power up and power down of multiple power supplies
Power up and power down control
(switching or linear regulators). By staggering the startup se-
Input voltage range of 2.7V to 5.5V
quence, it is possible to avoid latch conditions or large in-rush
Small footprint MSOP-8 package
currents that can affect the reliability of the system.
Low quiescent current of 80 µA
Available in MSOP-8 package, the Power Sequencer con-
tains a precision enable pin and three open drain output flags. Output invert feature
Upon enabling the LM3881, the three output flags will se- Timing controlled by small value external capacitor quentially release, after individual time delays, permitting the connected power supplies to startup. The output flags will fol-
Applications
low a reverse sequence during power down to avoid latch
conditions. Time delays are defined using an external capac- Multiple Supply Sequencing
itor and the output flag states can be inverted by the user. Microprocessor / Microcontroller Sequencing
FPGA Sequencing
Typical Application Circuit
© 2008 National Semiconductor Corporation www.national.com
Page Summary Contents For National Semiconductor LM3881 Power Sequencer Data Sheet
Manual Details
| Brand | National |
|---|---|
| Pages | 14 |
| File Size | 242.43 KB |
| Published | June 15, 2026 |
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Frequently Asked Questions
What does the LM3881 power sequencer help avoid when powering multiple supplies?
It avoids latch conditions or large in-rush currents by staggering the startup sequence of connected power supplies.
How is the timing for the sequential power-up delays defined?
The time delays are specified using an external capacitor, along with the control input pin.
What is the acceptable operating voltage range (VCC) for this device?
The component operates across a supply voltage range of 2.7V to 5.5V.
Can I use this product in critical life support devices or systems?
No, it requires express prior written approval from the National Semiconductor Corporation CEO and General Counsel.