MIC2174

300kHz, Synchronous Buck Controller

Featuring Adaptive On-Time Control

Hyper Speed Control is a trademark of Micrel. Inc.

MLF and MicroLeadFrame are registered trademarks of Amkor Technology, Inc.

Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (

September 2009

M9999-090409-B

General Description

The Micrel MIC2174 is a fixed frequency, synchronous

buck controller featuring adaptive on-time control. The

MIC2174 operates over an input supply range of 3V to

40V, switches at a constant frequency of 300kHz and is

capable of driving 25A of output current. The output

voltage is adjustable down to 0.8V.

A unique Hyper Speed Control™ architecture allows for

ultra fast transient response while reducing the output

controlled architecture. A UVLO is provided to ensure

proper operation under power-sag conditions to prevent

the external power MOSFET from overheating. A soft start

is provided to reduce inrush current. Foldback current limit

and “hiccup” mode short-circuit protection ensure FET and

load protection.

The MIC2174 is available in a 10-pin MSOP (MAX1954A-

compatible) package with a junction operating range from

–40

°C to +125°C.

All support documentation can be found on Micrel’s web

site at: www.micrel.com.

Features

•

Hyper Speed Control™ architecture enables

–

–

Smaller output capacitors than competitors

•

3V to 40V input voltage

•

Stable with zero-ESR output capacitor

•

300kHz switching frequency

•

Output down to 0.8V with ±1% FB accuracy

•

Up to 94% efficiency

•

Foldback current limit and “hiccup” mode short-circuit

protection

•

6ms Internal soft start

•

Thermal shutdown

•

Pre-bias output safe

•

–40

°C to +125°C junction temperature range

•

Available in 10-pin MSOP package

Applications

•

Wide input power supply

•

Industrial Equipments

•

Distributed DC power systems

•

Automotive applications

•

PCs and servers

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Typical Application

MIC2174: Synchronous Buck Controller Featuring Adaptive On-Time Control

12V to 3.3V Efficiency

50

55

60

65

70

75

80

85

90

95

100

02

4

6

8

10

OUTPUT CURRENT (A)

VIN=5V