MP2303A – 3A, 28V, 360kHz SYNCHRONOUS RECTIFIED, STEP-DOWN CONVERTER

MP2303A Rev.1.1

www.MonolithicPower.com

4

7/25/2012

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PIN FUNCTIONS

Pin #

Name Description

1

BS

High-Side Gate Drive Boost Input. BS supplies the drive for the high-side N-Channel MOSFET

switch. Connect a 0.01μF or greater capacitor from SW to BS to power the high side switch.

2

IN

Power Input. IN supplies the power to the IC, as well as the step-down converter switches.

Drive IN with a 4.7V to 28V power source. Bypass IN to GND with a suitably large capacitor to

eliminate noise on the input to the IC. See Input Capacitor.

3

SW

Power Switching Output. SW is the switching node that supplies power to the output. Connect

the output LC filter from SW to the output load. Note that a capacitor is required from SW to

BS to power the high-side switch.

4

GND

Ground (Connect Exposed Pad to Pin 4)

5

FB

Feedback Input. FB senses the output voltage to regulate that voltage. Drive FB with a

resistive voltage divider from the output voltage. The feedback threshold is 0.80V. See Setting

the Output Voltage

.

6

COMP

Compensation Node. COMP is used to compensate the regulation control loop. Connect a

series RC network from COMP to GND to compensate the regulation control loop. In some

cases, an additional capacitor from COMP to GND is required. See Compensation

Components.

7

EN

Enable Input. EN is a digital input that turns the regulator on or off. Drive EN high to turn on

the regulator, drive it low to turn it off. Connect EN with IN through a resistive voltage divider

for automatic startup. Do not float this pin.

8

SS

Soft-start Control Input. SS controls the soft-start period. Connect a capacitor from SS to GND

to set the soft-start period. A 0.1μF capacitor sets the soft-start period to 15ms. To disable the

soft-start feature, leave SS unconnected.