MP8774

– 18V, 12A, SYNCHRONOUS, STEP-DOWN CONVERTER

MP8774 Rev. 1.0

www.MonolithicPower.com

13

1/15/2018

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PIN FUNCTIONS

Package

Pin #

Name

Description

1, 15

NC

No connection. NC must be left floating.

2

BST

Bootstrap. Connect a capacitor between SW and BST to form a floating supply across the

high-side switch driver. A

BST resistor less than 4.7Ω is recommended.

3

EN

Enable. Pull EN high to enable the MP8774. When floating, EN is pulled down to GND and

disabled by an internal 3.3

MΩ resistor.

4

FB

Feedback. FB sets the output voltage when connected to the tap of an external resistor

divider between output and GND.

5

AGND

Signal ground. AGND is not connected to the system ground internally. Ensure that AGND

is connected to the system ground in the PCB layout.

6

SS

Soft start. Connect a capacitor across SS and GND to set the soft-start time to avoid inrush

current at start-up.

7

PG

Power good output. The output of PG is an open drain. PG changes state if UVP, OCP,

OTP, or OV occurs.

8

VIN

Supply voltage. The MP8774 operates from a 3 - 18V input rail. A capacitor (C1) is needed

to decouple the input rail. Use a wide PCB trace to make the connection.

9 - 13

PGND

System ground. PGND is the reference ground of the regulated output voltage. PGND

requires careful consideration during the PCB layout. PGND is recommended to be

connected to GND with coppers and vias.

14

VCC

Internal bias supply output. Decouple VCC with a 1µF capacitor. Place the VCC capacitor

close to VCC and GND.

16

SW

Switch output. Connect SW with a wide PCB trace.