MP4570 – 3A, 55V, SYNCHRONOUS STEP DOWN CONVERTER

MP4570 Rev. 1.01

www.MonolithicPower.com

7

1/4/2017

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PIN FUNCTIONS

Pin #

Name

Description

1

COMP

Compensation Networks Setting. Please connect an external resistor series with a

capacitor between this pin and GND.

2

FB

Feedback. This is the input to the PWM comparator. Please put an external resistive

divider connected between the output and GND.

3

FREQ

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

switching frequency. If external SYNC clock is applied to this pin, the converter will

follow this SYNC clock frequency.

4

EN

Enable Input. Pulling this pin below the specified threshold shuts the chip down.

There is no internal pull-up or pull-down circuit, so do not float the pin.

5

BST

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

MOSFET driver. Connect a capacitor between this pin and SW pin.

6,7,8

VIN

Input Supply. This supplies power to all the internal control circuitry, VDD regulator. A

decoupling capacitor to ground must be placed close to this pin to minimize switching

spikes.

9,12

NC

Not connected pin. Please float this pin in the application.

10,11

SW

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

13,14,

15, Exposed

Pad

GND

Power ground pin for internal power MOSFETs.

16

VDD

Power for internal MOSFET driver and BST charging circuit.

17

BIAS

For better thermal performance, please connect this pin to external 5V source, VDD

and internal circuit will be powered by BIAS. Since there is a diode inside between

the BIAS pin and the internal circuit, please float this pin or connected to GND if not

used.

18

PG

Power good indication. Please connect a resistor to a pull up power source if used.

19

SS

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

pin and GND to set soft-start time externally. Floating the pin will activate the internal

0.5ms soft-start setting.

20

ANGD Ground for internal logic and signal circuit.