PGOOD

VIN

PGND

SW

VOUT

RT

AGND

FB

EN/SYNC

PGOOD

Logic

+

+

VREF

Comp

Power

Stage

and

Control

Logic

Thermal

Shutdown

Shutdown

Logic

OCP

VIN

UVLO

Oscillator

Soft

Start

Sync

Detect

Precision

Enable

Copyright © 2017, Texas Instruments Incorporated

10

LMZM33602

SNVSAO4 – DECEMBER 2017

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Copyright © 2017, Texas Instruments Incorporated

7 Detailed Description

7.1 Overview

The LMZM33602 is a full-featured, 36-V input, 2-A, synchronous step-down converter with PWM, MOSFETs,

shielded inductor, and control circuitry integrated into a low-profile, overmolded package. The device integration

enables small designs, while providing the ability to adjust key parameters to meet specific design requirements.

The LMZM33602 provides an output voltage range of 1 V to 18 V. An external resistor divider is used to adjust

the output voltage to the desired value. The switching frequency can also be adjusted, by either an external

resistor or a sync signal, which allows the LMZM33602 to accommodate a variety of input and output voltage

conditions as well as optimize efficiency. The device provides accurate voltage regulation over a wide load range

by using a precision internal voltage reference. Input undervoltage lockout is internally set at 3.6 V (typical), but

can be adjusted upward using a resistor divider on the EN/SYNC pin of the device. The EN/SYNC pin can also

be pulled low to put the device into standby mode to reduce input quiescent current. A power-good signal is

provided to indicate when the output is within its nominal voltage range. Thermal shutdown and current limit

features protect the device during an overload condition. An 18-pin, QFN package that includes exposed bottom

pads provides a thermally enhanced solution for space-constrained applications.

7.2 Functional Block Diagram