MP2229 – 21V, 6A SYNCHRONOUS STEP-DOWN CONVERTER

MP2229 Rev. 1.0

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5

2/12/2015

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PIN FUNCTIONS

Package

Pin #

Name Description

1, 12,

13, 14

GND

Ground. Connect GND pins with larger copper areas to the negative terminals of the

input and output capacitors.

2, 11

SW

Switch Output. Use wide PCB traces to make the connection.

3, Exposed

Pad

IN

Supply Voltage Input. The MP2229 operates from a 4.5V to 21V input rail. Requires a

low ESR and a low-inductance capacitor to decouple the input rail. Place the input

capacitor very close to IN and connect it with wide PCB traces and multiple vias.

4

EN

Enable. EN high enables the MP2229. EN sources 2.3μA. Float EN to enable the

MP2229 automatically.

5

LPM

Low-Power Mode Input. An active-high signal enables low-power mode operation.

Connect LPM to GND to disable the converter and make the converter operate

constantly in CCM.

6

FB

Feedback. Connect to the tap of an external resistor divider from the output to GND to

set the output voltage.

7

SS

Soft-Start. Connect an external capacitor to program the soft-start time for the switch-

mode regulator.

8

FREQ/

SYNC

Switching Frequency Program Input. Connect a resistor from FREQ/SYNC to GND to

set the switching frequency. Also, FREQ/SYNC serves as a frequency-synchronous

clock input.

9

VCC

Internal Bias Supply. Internal 5V LDO output. Decouple with 0.1µF capacitor. The

decouple capacitor must be close enough to VCC to increase noise immunity.

10

BST

Bootstrap. Requires a capacitor connected between SW and BST to form a floating

supply across the high-side switch driver. A 10Ω resistor placed between SW and the

BST cap is recommended strongly to reduce the SW spike voltage.