MIC2571_02 Datasheet, PDF (1/12 Pages) Micrel Semiconductor – Single-Cell Switching Regulator

MIC2571
Micrel
MIC2571
Single-Cell Switching Regulator
Final Information
General Description
Micrel’s MIC2571 is a micropower boost switching regulator
that operates from one alkaline, nickel-metal-hydride cell, or
lithium cell.
The MIC2571 accepts a positive input voltage between 0.9V
and 15V. Its typical no-load supply current is 120µA.
The MIC2571 is available in selectable fixed output or adjust-
able output versions. The MIC2571-1 can be configured for
2.85V, 3.3V, or 5V by connecting one of three separate
feedback pins to the output. The MIC2571-2 can be config-
ured for an output voltage ranging between its input voltage
and 36V, using an external resistor network.
The MIC2571 has a fixed switching frequency of 20kHz. An
external SYNC connection allows the switching frequency to
be synchronized to an external signal.
The MIC2571 requires only four components (diode, induc-
tor, input capacitor and output capacitor) to implement a
boost regulator. A complete regulator can be constructed in
a 0.3 in² area.
All versions are available in an 8-lead MSOP with an operat-
ing range from –40°C to +85°.
Features
• Operates from a single-cell supply
0.9V to 15V operation
• 120µA typical quiescent current
• Complete regulator fits 0.3 in² area
• 2.85V/3.3V/5V selectable output voltage (MIC2571-1)
• Adjustable output up to 36V (MIC2571-2)
• 1A current limited pass element
• Frequency synchronization input
• 8-lead MSOP package
Applications
• Pagers
• LCD bias generator
• Battery-powered, hand-held instruments
• Palmtop computers
• Remote controls
• Detectors
• Battery Backup Supplies
Typical Applications
1V to1.5V
1 Cell
C1*
47µF
16V
L1
150µH
8
IN
SW ¹
2.85V ⁶
MIC2571-1 _3.3V 5
5V ⁴
SYNC GND
7
2
D1
MBR0530
5V/5mA
C2
47µF
16V
* Needed if battery is ≥ 4" from MIC2571
Circuit size < 0.3 in² excluding C1
Single-Cell to 5V DC-to-DC Converter
1V to1.5V
1 Cell
C1*
47µF
16V
L1
150µH
8
IN
SW ¹
2.85V ⁶
MIC2571-1 _3.3V 5
5V ⁴
SYNC GND
7
2
D1
MBR0530
3.3V/8mA
C2
47µF
16V
* Needed if battery is ≥ 4" from MIC2571
Circuit size < 0.3 in² excluding C1
Single-Cell to 3.3V DC-to-DC Converter
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 [phone] • fax + 1 [phone] • http://www.micrel.com
1997
1
MIC2571