LM3881
www.ti.com
SNVS555C –JANUARY 2008–REVISED APRIL 2013
LM3881 Power Sequencer
Check for Samples: LM3881
1
FEATURES
DESCRIPTION
The LM3881 Power Sequencer offers the easiest
method to control power up and power down of
multiple power supplies (switching or linear
regulators). By staggering the startup sequence, it is
possible to avoid latch conditions or large in-rush
currents that can affect the reliability of the system.
2
•
•
•
•
•
•
•
Easiest Method to Sequence Rails
Power Up and Power Down Control
Input Voltage Range of 2.7V to 5.5V
Small Footprint VSSOP-8 Package
Low Quiescent Current of 80 µA
Output Invert Feature
Available in VSSOP-8 package, the Power
Sequencer contains a precision enable pin and three
open drain output flags. Upon enabling the LM3881,
the three output flags will sequentially release, after
individual time delays, permitting the connected
power supplies to startup. 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.
Timing Controlled by Small Value External
Capacitor
APPLICATIONS
•
•
•
Multiple Supply Sequencing
Microprocessor / Microcontroller Sequencing
FPGA Sequencing
Typical Application Circuit
Connection Diagram
Input Supply
(2.7 Vœ 5.5V)
8
7
6
1
2
3
VCC
FLAG1
FLAG2
LM3881
EN
GND
INV
LM3881
FLAG3
TADJ
VCC
4
5
EN
Flag1
Flag2
Flag3
FLAG1
FLAG2
INV
FLAG3
TADJ
Figure 1. Top View
VSSOP-8 Package
GND
CADJ
PIN DESCRIPTIONS
Pin #
Name
Function
1
2
3
4
5
6
7
8
VCC
Input Supply
EN
Precision Enable
Ground
GND
INV
Output Logic Invert
Timer Adjust
TADJ
FLAG3
FLAG2
FLAG1
Open Drain Output #3
Open Drain Output #2
Open Drain Output #1
1
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
All trademarks are the property of their respective owners.
2
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2008–2013, Texas Instruments Incorporated