MIC4721

1.5A 2MHz Integrated Switch

Buck Regulator

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

May 2007

1

M9999-052907-A

General Description

The Micrel MIC4721 is a high efficiency PWM buck (step-

down) regulators that provides up to 1.5A of output

current. The MIC4721 operates at 2MHz and has

proprietary internal compensation that allows a closed loop

bandwidth of over 200KHz.

The low on-resistance internal p-channel MOSFET of the

MIC4721 allows efficiencies up to 94%, reduces external

components count and eliminates the need for an

expensive current sense resistor.

The MIC4721 operates from 2.7V to 5.5V input and the

output can be adjusted down to 1V. The devices can

operate with a maximum duty cycle of 100% for use in low-

dropout conditions.

The MIC4721 is available in the 10-pin MSOP package

with a junction operating range from –40°C to +125°C.

Data sheets and support documentation can be found on

Micrel’s web site at: www.micrel.com.

Features

• 2.7 to 5.5V supply voltage

• 2MHz PWM mode

• Output current to 1.5A

• Up to 94% efficiency

• 100% maximum duty cycle

• Adjustable output voltage option down to 1V

• Ultra-fast transient response

• Ultra-small external components

Stable with a 1µH inductor and a 4.7µF output capacitor

• Fully integrated 1.5A MOSFET switch

• Micropower shutdown

• Power Good pin

• Thermal shutdown and current limit protection

• Pb-free 10-pin MSOP package

• –40°C to +125°C junction temperature range

Applications

• FPGA/DSP/ASIC applications

• General point of load

• Broadband communications

• DVD/TV recorders

• Point of sale

• Printers/Scanners

• Set top boxes

• Computing peripherals

• Video cards

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Typical Application

1.5A 2MHz Buck Regulator

76

78

80

82

84

86

88

90

92

94

0 0.2 0.4 0.6 0.8

1.2 1.4 1.6

OUTPUT CURRENT (A)

1.0