November 2003

1

M9999-111803

MIC2168

Micrel

MIC2168

1MHz PWM Synchronous Buck Control IC

General Description

The MIC2168 is a high-efficiency, simple to use 1MHz PWM

synchronous buck control IC housed in a small MSOP-10

package. The MIC2168 allows compact DC/DC solutions

with a minimal external component count and cost.

The MIC2168 operates from a 3V to 14.5V input, without the

need of any additional bias voltage. The output voltage can

be precisely regulated down to 0.8V. The adaptive all

N-Channel MOSFET drive scheme allows efficiencies over

95% across a wide load range.

The MIC2168 senses current across the high-side N-Chan-

nel MOSFET, eliminating the need for an expensive and

lossy current-sense resistor. Current limit accuracy is main-

tained by a positive temperature coefficient that tracks the

increasing R

and space are saved by the internal in-rush-current limiting

digital soft-start.

The MIC2168 is available in a 10-pin MSOP package, with a

wide junction operating range of –40

°C to +125°C.

All support documentation can be found on Micrel’s web

site at www.micrel.com.

Typical Application

1.2

µH

3.3V

VDD

COMP/EN

VIN

CS

FB

GND

LSD

BST

1k

Ω

10k

Ω

4k

Ω

3.24k

Ω

4.7

µF

100

µF

0.1

µF

100nF

IRF7821

SD103BWS

IRF7821

100pF

HSD

VSW

MIC2168

150

µF x 2

MIC2168 Adjustable Output 1MHz Converter

Features

• 3V to 14.5V input voltage range

• Adjustable output voltage down to 0.8V

• Up to 95% efficiency

• 1MHz PWM operation

• Adjustable current-limit senses high-side N-Channel

MOSFET current

• No external current sense resistor

• Adaptive gate drive increases efficiency

• Ultra-fast response with hysteretic transient recovery

mode

• Overvoltage protection protects the load in fault

conditions

• Dual mode current limit speeds up recovery time

• Hiccup mode short-circuit protection

• Internal soft-start

• Dual function COMP and EN pin allows low-power

shutdown

• Small size MSOP 10-lead package

Applications

• Point-of-load DC/DC conversion

• Set-top boxes

• Graphic cards

• LCD power supplies

• Telecom power supplies

• Networking power supplies

• Cable modems and routers

Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com

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02468

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I

MIC2168 Efficiency

V

V