MP8861 – 2.85V - 18V, 6A, SYNCHRONOUS, STEP-DOWN CONVERTER

MP8861 Rev. 1.1

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13

5/28/2020

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PIN FUNCTIONS

QFN-14

Pin#

Name

Description

1

BST

Bootstrap. A capacitor is required between SW and BST to form a floating supply

across the high-side switch driver.

2

SW

Switch output. Connect SW using a wide PCB trace.

3

SCL

I2C serial clock.

4

SDA

I2C serial data.

5

EN

Enable. Set EN high to enable the MP8861. EN has a 1.5MΩ internal pull-down resistor

to GND. EN is a high-voltage pin, so it can be connected to VIN directly for automatic

start-up.

6

A0

I2C address set-up. Connect a resistor divider from VCC to A0 to set different I2C

addresses.

7

PG

Power good indication. PG is an open-drain structure. PG is de-asserted if the output

voltage is out of the regulation window.

8

PGND

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

and requires special consideration during PCB layout. Connect PGND to the ground

plane with copper traces and vias.

9

VIN

Supply voltage. The MP8861 operates from a 2.85V to 18V input rail. Decouple the

input rail with a ceramic capacitor. Connect VIN using a wide PCB trace.

10

VOUT

Output voltage sense. Connect VOUT to the positive terminal of the load.

11

FB

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

to set the output voltage.

12

SS

Soft start set-up. Connect a capacitor from SS to ground to set the soft-start time.

13

VCC

Internal LDO regulator output. Decouple VCC with a 0.47µF capacitor.

14

AGND

Signal ground. If AGND is not connected to PGND internally, ensure that AGND is

connected to PGND in the PCB layout.