MIC5255
Micrel
MIC5255
150mA Low Noise
µ
Cap CMOS LDO
General Description
The MIC5255 is an efficient, precise CMOS voltage regulator
optimized for ultra-low-noise applications. It offers 1% initial
accuracy, extremely-low dropout voltage (135mV at 150mA)
and low ground current (typically 90µA). The MIC5255 pro-
vides a very-low-noise output, ideal for RF applications
where a clean voltage source is required. A noise bypass pin
is also available for further reduction of output noise.
Designed specifically for handheld and battery-powered de-
vices, the MIC5255 provides a TTL-logic-compatible enable
pin. When disabled, power consumption drops nearly to zero.
The MIC5255 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, faster
transient response, and an active clamp to speed up device
turn-off. Available in the 6-pin 2mm
×
2mm MLF™ package,
the IttyBitty® SOT-23-5 package and the new Thin SOT-23-
5, which offers the same footprint as the standard IttyBitty®
SOT-23-5, but only 1mm tall. The MIC5255 offers a range of
output voltages.
All support documentation can be found on Micrel’s web
site at www.micrel.com.
Features
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Input voltage range: 2.7V to 6.0V
Thin SOT package: 1mm height SOT-23-5
Ultra-low output noise: 30µV(rms)
Stability with ceramic output capacitors
Ultra-low dropout: 135mV @ 150mA
High output accuracy:
1.0% initial accuracy
2.0% over temperature
Low quiescent current: 90µA
Tight load and line regulation
TTL-Logic-controlled enable input
“Zero” off-mode current
Thermal shutdown and current limit protection
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Applications
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Cellular phones and pagers
Cellular accessories
Battery-powered equipment
Laptop, notebook, and palmtop computers
Consumer/personal electronics
Typical Application
MIC5255-x.xBM5
1
2
3
4
5
C
IN
= 1.0µF
Ceramic
Enable
Shutdown
V
IN
V
OUT
C
OUT
= 1.0µF
Ceramic
C
BYP
= 0.01µF
ENABLE
SHUTDOWN
V
IN
EN
MIC5255-x.xBML
1
2
3
6
5
4
V
OUT
C
BYP
(optional)
C
OUT
EN
EN (pin 3) may be
connected directly
to IN (pin 1).
Ultra-Low-Noise Regulator Application
IttyBitty is a registered trademark of Micrel, Inc.
Micro
LeadFrame and MLF are trademarks of Amkor Technology.
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000• http://www.micrel.com
August, 2004
1
M0385-080204