April 2005

1

M9999-042205

MIC2145

Micrel, Inc.

MIC2145

High Efficiency 2.5W Boost Converter

General Description

The MIC2145 is a small size boost switching regulator that

can provide over 2.5W of output power. The input voltage

range is between 2.4V to 16V, making the device suitable for

one-cell Li-Ion and 3- to 4-cell alkaline/NiCad/NiMH applica-

tions. The output voltage of the MIC2145 can be adjusted up

to 16V.

The MIC2145 is well suited for portable, space-sensitive

applications. Its typical 450kHz operation allows small sur-

face mount external components to be used. The MIC2145

has a low quiescent current of 200µA, and a typical shutdown

current of 0.5µA. The MIC2145 is capable of high efficiencies

in a small board area.

The MIC2145 features a low-on resistance internal switch

that allows it to provide over 2.5W of output power. The peak

switch current can be programmed through an external

resistor. This allows the user to set the peak switch current at

the level where maximum efficiency occurs. It also allows the

user to further optimize for efficiency and inductor size by

setting the peak current below the level of inductor saturation.

The MIC2145 is available in an MSOP-8 and 3mm×3mm

MLF™-10L package with an ambient operating temperature

range from –40°C to +85°C.

Typical Application

L1

10

µH

D1

MIC2145BMM

RSET

PGND

EN

SW

10V/150mA

VDD

FB

SGND

I Limit

3.0V to 5.0V

SS

10

µF/6.3V

10

µF/16V

15

6

7

8

4

3

2

60

65

70

75

80

85

90

10

100

1000

OUTPUT CURRENT (mA)

10V Output

Efficiency

V

Adjustable Output Boost Converter with Programmable Peak Switch Current

Features

•2.4V to 16V input voltage

• Output adjustable to 16V

•Programmable peak current limit

• Soft start

• Up to 450kHz switching frequency

•0.5µA shutdown current

• 200µA quiescent current

• Capable of 5V/ 500mA output with 3.3V input

• Achieves over 85% efficiency

•Implements low power BOOST, SEPIC, and FLYBACK

topologies

• MSOP-8 and 3mm×3mm MLF™-10L

Applications

•Flash LED driver

• LCD bias supply

• White LED driver

• DSL bias supply

• Local 3V to 5V conversion

Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com

Ordering Information

Part Number

Voltage

Ambient

Standard

Pb-Free

Temp. Range

Package

MIC2145BMM

MIC2145YMM

Adj

–40°C to +85°C

8-lead MSOP

MIC2145BML

MIC2145YML

Adj

–40°C to +85°C

10-lead MLF™

MLF and MicroLeadFrame are trademarks of Amkor Technologies, Inc.