LM3881 Simple Power Sequencer With Adjustable Timing

1 Features

• Easiest Method to Sequence Rails
• Power-Up and Power-Down Control
• Tiny Footprint
• Low Quiescent Current of 80 µA
• Input Voltage Range of 2.7 V to 5.5 V
• Output Invert Feature
• Timing Controlled by Small Value External Capacitor

2 Applications

• Security Cameras
• Servers
• Networking Elements
• FPGA Sequencing
• Microprocessor and Microcontroller Sequencing
• Multiple Supply Sequencing

3 Description

The LM3881 Simple Power Sequencer offers the easiest method to control power up and power down of multiple power supplies (switching or linear regulators). By staggering the start-up sequence, it is possible to avoid latch conditions or large inrush currents that can affect the reliability of the system.

Available in VSSOP-8 package, the Simple Sequencer contains a precision enable pin and three open-drain output flags. When the LM3881 is enabled, the three output flags will sequentially release, after individual time delays, thus permitting the connected power supplies to start up. The output flags will follow a reverse sequence during power down to avoid latch conditions. Time delays are defined using an external capacitor and the output flag states can be inverted by the user.

1. For all available packages, see the orderable addendum at the end of the datasheet.

Typical System Application

4 Revision History

Changes from C Revision (April 2013) to D Revision

• Added Handling Rating table, Feature Description section, Device Functional Modes, Application and Implementation section, Power Supply Recommendations section, Layout section, Device and Documentation Support section, and Mechanical, Packaging, and Orderable Information section Go

Changes from B Revision (April 2013) to C Revision

• Changed layout of National Data Sheet to TI formatGo

5 Pin Configuration and Functions

VSSOP Package

8-Pin DGK

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