MPM3620 – SYNCHRONOUS STEP-DOWN MODULE WITH INTEGRATED INDUCTOR

MPM3620 Rev. 1.1

www.MonolithicPower.com

11

2/12/2015

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© 2015 MPS. All Rights Reserved.

PIN FUNCTIONS

Package

Pin #

Name

Description

1

FB

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

AGND to set the output voltage. To prevent current-limit runaway during a short-circuit

fault, the frequency foldback comparator lowers the oscillator frequency when the FB

voltage is below 400mV. Place the resistor divider as close as possible to FB. Avoid

placing vias on the FB traces.

2

VCC

Internal 5V LDO Output. The module integrates a LDO output capacitor, so there is no

need to add an external capacitor.

3

AGND

Analog Ground. Reference ground of logic circuit. AGND is connected internally to

PGND, so there is no need to add any external connections to PGND.

4, 5, 6

SW

Switch Output. A large copper plane is recommended on pins 4, 5, and 6 to improve

thermal performance.

7, 8, 9

OUT

Power Output. Connect load to OUT. An output capacitor is needed.

10, 15,

19, 20

NC

No Connection. DO NOT CONNECT. NC must be left floating.

11

BST

Bootstrap. A bootstrap capacitor is integrated internally, so an external connection is

not needed.

12, 13, 14

PGND

Power Ground. Reference ground of the power device. PCB layout requires extra care

(please see recommended “PCB Layout Guidelines” on page 19). For best results,

connect to PGND with copper and vias.

16

IN

Supply Voltage. IN supplies power for the internal MOSFET and regulator. The

MPM3620 operates from a +4.5V to +24V input rail. It requires a low ESR and low-

inductance capacitor to decouple the input rail. Place the input capacitor very close to

IN and connect it with wide PCB traces and multiple vias.

17

EN

Enable. EN=high to enable the module. Leave EN floating or connect it to GND to

disable the module.

18

AAM

Advanced Asynchronous Modulation. AAM sources a 6.2μA current from an internal

5V supply. Float AAM or drive AAM high (>2.5V) to force the MPM3620 to operate in

continuous conduction mode (CCM). If AAM mode is required under light load, connect

a resistor to ground to program AAM voltage in the range of 0V to1V.