LM3881MME Datasheet, PDF (1/17 Pages) Texas Instruments – LM3881 Power Sequencer

LM3881
www.ti.com
SNVS555C – JANUARY 2008 – REVISED APRIL 2013
LM3881 Power Sequencer
Check for Samples: LM3881
FEATURES
1
•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
• Timing Controlled by Small Value External
Capacitor
APPLICATIONS
• Multiple Supply Sequencing
• Microprocessor / Microcontroller Sequencing
• FPGA Sequencing
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.
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.
Typical Application Circuit
Input Supply
(2.7 V ± 5.5V)
LM3881
C_ADJ
VCC
EN
FLAG1
INV
FLAG2
TADJ
FLAG3
GND
Flag 1
Flag 2
Flag 3
Connection Diagram
1
VCC
2
EN
3
GND
INV ⁴
LM3881
8
FLAG1
7
FLAG2
6
FLAG3
5 _TADJ
Figure 1. Top View
VSSOP-8 Package
Pin #
1
2
3
4
5
6
7
8
PIN DESCRIPTIONS
Name
VCC
EN
GND
INV
TADJ
FLAG3
FLAG2
FLAG1
Function
Input Supply
Precision Enable
Ground
Output Logic Invert
Timer Adjust
Open Drain Output #3
Open Drain Output #2
Open Drain Output #1
1
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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.
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