MP8652 – 15A, 14V, HIGH FREQUENCY STEP-DOWN WITH SYNCHRONOUS GATE DRIVER

MP8652 Rev. 0.9

www.MonolithicPower.com

4

10/26/2009

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PIN FUNCTIONS

Pin #

Name

Description

1

VCC

BG Driver Bias Supply. Decouple with a 1µF ceramic capacitor.

2

SYNCOUT

Timing output to drive another MP8652 (or similar device) SYNCIN for phase-shift

operation.

3

SYNCIN

frequency.

4

EN

On/Off Control.

5

SS/TRK

Soft-Start/Track Input. Connect a capacitor to ground.

6

FB

Feedback. An external resistor divider from the output to GND, tapped to the FB pin,

sets the output voltage. To prevent current limit run away during a short circuit fault

condition the frequency foldback comparator lowers the oscillator frequency when the

FB voltage is below 400mV.

7

COMP

Compensation. Connect R/C network to ground.

8

PG

The output of this pin is an open drain if the output voltage is within 10% of the

nominal voltage, otherwise it is LOW. If PG is initially at open drain, there is a 20µs

delay to pull PG if the output voltage is less than 10% regulation window.

9

BST

Bootstrap. This capacitor is needed to drive the power switch’s gate above the supply

voltage. It is connected between SW and BS pins to form a floating supply across the

power switch driver.

10, 18,

Exposed Pad

VIN

Supply Voltage. The MP8652 operates from a +4.5V to +14V unregulated input. C1 is

needed to prevent large voltage spikes from appearing at the input.

11-17

SW

Switch Output. These pins are fused together.

19

GATE

Gate Driver Output. Connect this pin to the synchronous MOSFET.

20

GND

Ground.