MIC2124

Constant Frequency, Synchronous

Current Mode Buck Controller

Hyper Speed Control™ Family

Hyper Speed Control and Any Capacitor are trademarks of Micrel, Inc.

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

June 2010

M9999-060810-D

General Description

The Micrel MIC2124 is a member of the Hyper Speed

Contro™l family of DC-DC controllers. It uses an adaptive

on-time current mode control scheme and operates at a

constant frequency.

The MIC2124 operates over a supply range of +3V to

operates at a fixed 300kHz switching frequency and can

be used to provide up to 25A of output current. The output

voltage is adjustable down to +0.8V.

The MIC2124 includes an EN/COMP pin that can be

pulled low to shut down the converter. The MIC2124

optimizes performance and ensures stability with external

compensation.

The UVLO is provided to ensure proper operation under

power-sag conditions and to make sure that the external

power MOSFET has enough voltage to work with. An

internal digital soft-start ensures reduced inrush current.

Cycle-by-cycle current limiting ensures FET protection.

The MIC2124 is available in a 10-pin MSOP package with

a junction temperature operating range from –40ºC to

+125ºC.

Features

•

+3V to +18V input voltage

•

25A output current capability

•

Any Capacitor

-

Zero ESR to high ESR

•

Output down to 0.8V with ±1% FB accuracy

•

Up to 94% efficiency

•

300kHz switching frequency

•

All N-Channel MOSFET design

•

Shutdown feature with EN/COMP

•

No current-sense resistor needed

•

Internal 4ms digital soft-start

•

Thermal shutdown

•

Pre-bias output safe

•

Cycle-by-Cycle foldback current-limit protection

•

10-pin MSOP package

•

–40ºC to +125ºC junction temperature range

Applications

•

Printers and scanners

•

Graphic and video cards

•

PCs and servers

•

Microprocessor core supply

•

Low-voltage distributed power

•

Telecommunication and networking

•

Set-top box, gateways and router

Typical Application

MIC2124 Adjustable Output 300kHz Buck Converter

12V to 3.3V Efficiency

60

70

80

90

100

02

46

8

10

OUT PUT CURRENT (A)