MP2227 – 24V, 3A, 1.3MHz SYNCHRONOUS STEP-DOWN CONVERTER

MP2227 Rev. 1.1

www.MonolithicPower.com

4

11/21/2011

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PIN FUNCTIONS

Pin #

Name

Description

1

FB

Feedback. This is the input to the error amplifier. An external resistive divider connected

between the output and GND is compared to the internal 0.8V reference to set the

regulation voltage.

2

POK

Open Drain Power Good Output. “HIGH” output indicates VOUT is within ±10% window.

“LOW” output indicates VOUT is out of ±10% window. POK is pulled down in shutdown.

3

IN

Input Supply. This supplies power to the high side switch. A decoupling capacitor to ground

is required close to this pin to reduce switching spikes.

4, 5

GND

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

and output capacitors.

6,7

SW

Switch Node Connection to the Inductor. These pins connect to the internal high and low-

side power MOSFET switches. All SW pins must be connected together externally.

8

BST

Bootstrap. A capacitor between this pin and SW provides a floating supply for the high-side

gate driver.

9

VCC

Bias Supply. Provide 5V to this pin when the input voltage is less than 5V. Otherwise it

does not need external supply. This supplies power to both the internal control circuit and

the gate drivers. A decoupling capacitor to ground is required close to this pin.

10

EN/SYNC

Enable and Frequency Synchronization Input Pin. Forcing this pin below 0.4V shuts down

the part. Forcing this pin above 1.6V turns on the part. Applying a 1MHz to 2MHz clock

signal to this pin synchronizes the internal oscillator frequency to the external source. To

resistor.