MP4575

– 5A, 55V, SYNCHRONOUS, STEP-DOWN CONVERTER

MP4575 Rev. 1.0

www.MonolithicPower.com

12

8/16/2016

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PIN FUNCTIONS

Pin #

Name

Description

1

COMP

Compensation network setting. Connect an external resistor in series with a

capacitor between COMP and GND.

2

FB

Feedback. FB is the input to the PWM comparator. Place an external resistor

divider between the output and GND.

3

FREQ

Switching frequency setting. Connect a resistor from FREQ to GND to set the

switching frequency. If an external synchronous clock is applied to FREQ, the

converter follows this clock

’s frequency.

4

EN

Enable input. Pull EN below the specified threshold to shut down the MP4575.

There is no internal pull-up or pull-down circuit. Do not float EN.

5

BST

Bootstrap. BST is the positive power supply for the internal floating high-side

MOSFET driver. Connect a capacitor between BST and SW.

6, 7, 8

VIN

Input supply. VIN supplies power to all of the internal control circuitries and VDD

regulator. A decoupling capacitor to ground must be placed close to VIN to

minimize switching spikes.

9, 12

NC

No connection. Leave NC floating.

10, 11

SW

Switch node. SW is the output node from the internal high-side MOSFET source.

13, 14, 15,

Exposed Pad

GND

Power ground for the internal power MOSFETs.

16

VDD

Power for the internal MOSFET driver and BST charging circuit.

17

BIAS

Optional supply for the internal circuit. For better thermal performance, connect

BIAS to an external 5V source. VDD and the internal circuit are powered by BIAS.

Since there is a diode between BIAS and the internal circuit, leave BIAS floating or

connect it to GND if BIAS is not used.

18

PG

Power good indicator. Connect a resistor to a pull-up power source if used.

19

SS

Optional external soft-start time setting. Connect an external capacitor between

SS and GND to set the soft-start time externally. Float SS to activate the internal

0.5ms soft-start setting.

20

AGND

Ground for internal logic and signal circuit.