MP2128 – 3MHz, 1A SYNCHRONOUS STEP-DOWN CONVERTER

MP2128 Rev. 0.9

www.MonolithicPower.com

5

7/20/2009

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PIN FUNCTIONS

SOT23

Pin #

QFN

Pin #

Name

Description

1

8

EN

Regulator Enable Control Input. Drive EN above 1.6V to turn on the part. Drive EN

below 0.4V to turn it off.

2

2,4

GND

Ground.

3

5,6

SW

Power Switch Output. Inductor connection to drains of the internal PFET and

NFET switches.

4

3

IN

Supply Input. Bypass to GND with a 4.7µF or bigger value ceramic capacitor.

5

1

FB

Feedback Input. Connect FB to the center point of the external resistor divider. The

regulated feedback voltage is 0.6V.

FUNCTIONAL BLOCK DIAGRAM

Figure 1— Functional Block Diagram