MP3435 – 19A, 600kHz, 22V SYNCHRONOUS BOOST WITH INPUT DISCONNECT

MP3435 Rev. 1.0

MonolithicPower.com

3

11/30/2021

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PIN FUNCTIONS

Pin #

Name

Description

1, 2

OUT

Power output. Connect OUT to the high-side MOSFET (HS-FET)

’s drain.

3

TM

Internal test pin. Only use in product test mode. Float TM in application.

4

BST

Bootstrap. BST powers the HS-FET driver.

5

SOUT

Samples the output voltage and charges the BST capacitor. VDD is powered from

SOUT when VSOUT exceeds VIN.

6

EN

Regulator on/off control input. Pull this pin high to turn on the internal regulator circuit;

pull it low to turn off the regulator circuit. An input above the EN turn-on threshold

enables the IC to start switching. When the EN pin is not used, connect EN to the input

source (through a 100kΩ pull-up resistor if VIN > 5.5V) for automatic start-up. This pin can

also configure VIN UVLO. Do not leave EN floating.

7

GATE

Driver for the input disconnect MOSFET. If this pin is floating or connected to the input

MOSFET gate, an external current-sense resistor is required. Connect GATE to ground

to use the internal current-sense circuit. Do not pull GATE down to ground through a

resistor.

8

SENSE

Voltage sense. The voltage sensed between SENSE and IN determines the external

current-sense signal. Connect SENSE to IN if the internal current-sense function is

selected.

9, 20

SW

Power switch. Connect SW to the internal low-side MOSFET (LS-FET)

’s drain and the

internal, synchronous HS-FET source. Connect the power inductor to SW.

10, 17,

18, 19

PGND

Power ground.

11

IN

Input supply. IN must be locally bypassed.

12

VDD

Internal bias supply. Decouple the VDD pin

with a 2.2μF ceramic capacitor, placed as

close to VDD as possible.

13

COMP

Compensation. Connect a capacitor and resistor in series to the analog ground for loop

stability.

14

FB

Feedback input. The reference voltage (VREF) is 1.225V. Connect a resistor divider from

output to FB.

15

SS

Soft-start control. Connect a soft-start capacitor (CSS) to SS. CSS is charged with a

constant current. Leave SS disconnected if soft start is not used.

16

AGND

Analog ground.