MIC22400

4A Integrated Switch Synchronous

Buck Regulator with Frequency

Programmable up to 4MHz

Ramp 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 (

February 2008

M9999-022108-A

General Description

The Micrel MIC22400 is a high efficiency 4A integrated

switch synchronous buck (step-down) regulator. The

MIC22400 is optimized for highest efficiency and achieves

over 90% efficiency while still switching at 1MHz over a

broad load range. The ultra high speed control loop keeps

the output voltage within regulation even under extreme

transient load swings commonly found in FPGAs and low

voltage ASICs. The output voltage can be adjusted down

to 0.7V to address all low voltage power needs. A full

range of sequence options are available with the

MIC22400. The enable/delay pin combined with the power

good pin allows multiple outputs to be sequenced in any

way on turn on and turn off. The RC (Ramp Control™) pin

allows the device to be connected to another MIC22400

family of products to keep the output voltages within a

certain ∆V on start up.

The MIC22400 is available in a 20-pin 3mm x 4mm MLF

®

and thermally enhanced 20-pin e-TSSOP 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

• Input voltage range: 2.6V to 5.5V

• Output voltage adjustable down to 0.7V

• Output current up to 4A

• Full sequencing and tracking ability

• Power on reset

• Efficiency > 90% across a broad load range

• Programmable frequency 800kHz to 4MHz

• Easy RC compensation

• Ultra fast transient response

• 100% maximum duty cycle

• Fully integrated MOSFET switches

• Micropower shutdown

• Thermal shutdown and current limit protection

• 20-pin e-TSSOP

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

Applications

• High power density point of load conversion

• Servers and routers

• DVD recorders

• Computing peripherals

• Base stations

• FPGAs, DSP and low voltage ASIC power

Typical Application

MIC22400 4A Synchronous Buck Regulator

60

65

70

75

80

85

90

95

100

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5

OUTPUT CURRENT (A)

Sequencing & Tracking