MP9459 – SYNCHRONOUS, STEP-DOWN CONVERTER W/ INTERNAL MOSFETS

MP9459 Rev. 1.0

www.MonolithicPower.com

2

1/13/2020

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ORDERING INFORMATION

Part Number*

Package

Top Marking

MSL Rating

MP9459GTF

SOT563 (1.

6mmх1.6mm)

See Below

1

* For Tape & Reel, add suffix

–Z (e.g. MP9459GTF–Z).

TOP MARKING

BPD: Product code of MP9459GTF

Y: Year code

LLL: Lot number

PACKAGE REFERENCE

TOP VIEW

SOT563

(1.6mmх1.6mm)

PIN FUNCTIONS

Pin #

Name Description

1

VIN

Supply voltage. The MP9459 operates from a 4.2V to 17V input rail. A capacitor (C1) is

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

2

SW

Switch output. Connect SW using a wide PCB trace.

3

GND

System ground. GND is the reference ground of the regulated output voltage. GND requires

additional consideration while designing the PCB layout. Connect GND with copper traces

and vias.

4

BST

Bootstrap. Connect a capacitor and a resistor between SW and BST to form a floating

supply across the high-side switch driver. Use a 1µF bootstrap capacitor.

5

EN

Enable. Drive EN high to enable the MP9459. For automatic start-up, connect EN to VIN with

a 100kΩ pull-up resistor.

6

FB

Feedback. To set the output voltage, connect FB to the tap of an external resistor divider

from the output to GND. The frequency foldback comparator lowers the oscillator frequency

when the FB voltage drops below 600mV. This prevents current-limit runaway during a short-

circuit fault.