MP8865

– SYNCHRONOUS STEP-DOWN CONVERTER

MP8865 Rev. 1.03

www.MonolithicPower.com

12

1/18/2018

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PIN FUNCTIONS

Pin #

Name

Description

1

VIN

Supply Voltage. The MP8865 operates from a 4.5V to 21V input rail. VIN requires a

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

2, 8

PGND

System Ground. Reference ground of the regulated output voltage. PGND requires special

consideration during PCB layout (see the

“PCB Layout Guidelines” section on page 24).

Connect PGND to GND with copper traces and vias.

3

EN/SYNC

Enable/Synchronize. EN=high to enable the MP8865. EN/SYNC has an

internal 1MΩ pull-

down resistor to ground.

4

PG

Power Good. Open-drain structure.

5

SDA

6

SCL

7

ADD

ground sets an additional addresses.

9

SW

Switch Output. Connect SW using a wide PCB trace.

10

BST

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

across the high-side switch driver.

11

VOUT

12

FB

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

set the output voltage in the FB control loop. Connecting FB to VCC sets the default

output voltage at 0.9V.

13

SS

Soft-Start. Connecting a capacitor from SS to ground sets the soft-start time.

14

VCC

Internal 5V LDO Regulator Output. Decouple with a 0.22µF capacitor.

15

AGND

Signal Ground. AGND is NOT connected internally to system ground. Ensure AGND is

connected to system ground in the PCB layout.