MIC2940A/2941A
Micrel
MIC2940A/2941A
1.25A Low-Dropout Voltage Regulator
Preliminary Information
General Description
The MIC2940A and MIC2941A are “bulletproof” efficient
voltage regulators with very low dropout voltage (typically
40mV at light loads and 350mV at 1A), and low quiescent
current (240µA typical). The quiescent current of the MIC2940A
increases only slightly in dropout, thus prolonging battery life.
Key MIC2940A features include protection against reversed
battery, fold-back current limiting, and automotive “load dump”
protection (60V positive transient).
The MIC2940 is available in both fixed voltage (3.3V, 5V, and
12V) and adjustable voltage configurations. The MIC2940A-
xx devices are three pin fixed voltage regulators. A logic-
compatible shutdown input is provided on the adjustable
MIC2941A, which enables the regulator to be switched on and
off.
Features
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High output voltage accuracy
Guaranteed 1.25A output
Low quiescent current
Low dropout voltage
Extremely tight load and line regulation
Very low temperature coefficient
Current and thermal limiting
Input can withstand –20V reverse battery and +60V
positive transients
Logic-controlled electronic shutdown
Output programmable from 1.24V to 26V(MIC2941A)
Available in TO-220, TO-263, TO-220-5, and TO-263-5
packages.
Battery Powered Equipment
Cellular Telephones
Laptop, Notebook, and Palmtop Computers
PCMCIA V
CC
and V
PP
Regulation/Switching
Bar Code Scanners
Automotive Electronics
SMPS Post-Regulator/ DC to DC Modules
Voltage Reference
High Efficiency Linear Power Supplies
Applications
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Pin Configuration
INPUT GROUND OUTPUT
TO-263 Package
(MIC2940A-xxBU)
1 2 3 4 5
TO-263-5 Package
(MIC2941ABU)
MIC2941A Pinout
1)
2)
3)
4)
5)
Adjust
Shutdown
Ground
Input
Output
1 2 3 4 5
1 2
3
Front View
INPUT GROUND OUTPUT
TO-220 Package
(MIC2940A-xxBT)
TO-220-5 Package
(MIC2941ABT)
The Tab is Ground on TO-220 and TO-263 packages
June 1999
1
MIC2940A/2941A