MIC2141_06 Datasheet, PDF (1/16 Pages) Micrel Semiconductor – Micropower Boost Converter

MIC2141
Micropower Boost Converter
General Description
Features
The MIC2141 is a micropower boost switching regulator
that can operate from 3- or 4-cell nickel-metal-hydride
batteries or a single Li-ion cell. This regulator employs a
constant 330kHz, fixed 18% duty-cycle, gated-oscillator
architecture.
The MIC2141 can be used in applications where the
output voltage must be dynamically adjusted. The device
features a control signal input which is used to
proportionally adjust the output voltage. The control signal
input has a gain of 6, allowing a 0.8V to 3.6V control signal
to vary a 4.8V to 22V output.
The MIC2141 requires only three external components to
operate and is available in a tiny 5-pin SOT-23 package for
space and power-sensitive portable applications. The
MIC2141 draws only 70µA of quiescent current and can
operate with an efficiency exceeding 85%.
Data sheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
• Implements low-power boost, SEPIC, or flyback
• 2.2V to 14V input voltage
• 330kHz switching frequency
• <2µA shutdown current
• 70µA quiescent current
• 1.24V bandgap reference
• Typical output current 1mA to 10mA
• SOT23-5 package
Applications
• LCD bias supply
• CCD digital camera supply
___________________________________________________________________________________________________________
Typical Application
V_C*
(from DAC)
10µH
MIC2141
1
5
2
3
4
Variable
V_OUT
4.0
3.5
3.0
2.5
2.0
1.5
10µF
1.0
0.5
00
DAC-Controlled LCD Bias Voltage Supply
Control Voltage
vs. Output Voltage
5 10 15 20 25
V_OUT (V)
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel [phone] • fax + 1 [phone] • http://www.micrel.com
December 2006
1
M9999-122006