MP8868 – SYNCHRONOUS STEP-DOWN CONVERTER

MP8868 Rev.1.1

www.MonolithicPower.com

12

5/15/2015

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PIN FUNCTIONS

QFN14

PIN#

Name

Description

1

BST

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

across the high-side switch driver.

2

SW

Switch Output. Connect using a wide PCB trace.

3

SCL

I

4

SDA

I

5

EN/SYNC

EN high to enable the MP8868. EN pin has internal 5.4uA pull-up current to 5V, so it

can auto startup when EN floating. Apply an external clock can to the EN pin to

change the switching frequency.

6

A0

I

to ground can set another different address.

7

PG

Power Good Indication. Open drain structure. PG switches low if the output voltage is

out of regulation window. PG only indicates UV condition.

8

PGND

System Power Ground. Reference ground of the regulated output voltage. Requires

special consideration during PCB layout. Connect to ground plane with copper traces

and vias.

9

VIN

Supply Voltage. The MP8868 operates from a 4.5V-to-17V input rail. Requires ceramic

capacitor to decouple the input rail. Connect using a wide PCB trace.

10

VOUT

Sense input of output voltage. Connect it to the positive terminal of loading.

11

FB

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

set the output voltage in FB control loop.

12

SS

Soft start pin. Connect a capacitor from SS to ground can set the soft start time.

13

VCC

Internal LDO regulator output. Decouple with 0.47µF capacitor.

14

AGND

Signal Ground. AGND is not internally directly connected to System Ground, make

sure AGND connected to system Ground in PCB layout.