MIC5247
Micrel, Inc.
MIC5247
150mA Low-Voltage
µCap
Linear Regulator
General Description
The MIC5247 is an efficient and precise, low-voltage CMOS
voltage regulator optimized for ultra-low noise applications.
The MIC5247 offers better than 1% initial accuracy and
85µA constant ground current over load (typically 85µA).
The MIC5247 provides a very low-noise output, ideal for
RF applications where quiet voltage sources are required.
A noise bypass pin is also available for further reduction of
output noise.
Designed specifically for handheld and battery-powered de-
vices, the MIC5247 provides a logic compatible enable pin.
When disabled, power consumption drops nearly to zero.
The MIC5247 also works with low-ESR ceramic capacitors,
reducing the amount of board space necessary for power
applications, critical in handheld wireless devices.
Key features include current limit, thermal shutdown, a push-
pull output for faster transient response, and an active clamp
to speed up device turnoff. Available in the 6-pin 2mm
×
2mm
MLF™ package and the IttyBitty
®
SOT-23-5 package, the
MIC5247 also offers a range of fixed output voltages.
All support documentation can be found on Micrel’s web site
at www.micrel.com.
Features
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Ultra-low noise
Low-voltage outputs
Load independent, ultra-low ground current: 85µA
150mA output current
Current limiting
Thermal shutdown
Tight load and line regulation
“Zero” off-mode current
Stability with low-ESR capacitors
Fast transient response
Logic-controlled enable input
Cellular phones and pagers
Cellular accessories
Battery-powered equipment
Laptop, notebook, and palmtop computers
PCMCIA V
CC
and V
PP
regulation/switching
Consumer/personal electronics
SMPS post-regulator/DC-to-DC modules
High-efficiency linear power supplies
Applications
Typical Application
V
IN
MIC5247-x.xBM5
1
2
Enable
Shutdown
5
V
OUT
C
OUT
ENABLE
SHUTDOWN
V
IN
EN
MIC5247-x.xBML
1
2
3
6
5
4
V
OUT
C
BYP
C
OUT
3
4
(optional)
EN
EN (pin 3) may be
connected directly
to IN (pin 1).
C
BYP
(optional)
Ultra-Low-Noise Regulator Application
Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
February 2006
1
M9999-022406
MICREL [ MICREL SEMICONDUCTOR ]
