+

-

+

-

CONTROL

LOGIC

DRIVER

HS CURRENT

SENSE

LS CURRENT

SENSE

OSCILLATOR

PWM

COMP.

ERROR

AMPLIFIER

MODE

LOGIC

RESET

CONTROL

SW

VIN

PGND

FB

EN

FPWM

INT. REG.

BIAS

BIAS

VCC

CBOOT

SYNC

AGND

*

*

* = Not used in -ADJ

RESET

1.0 V

Reference

ENABLE

LOGIC

Copyright © 2016, Texas Instruments Incorporated

10

LM53602, LM53603

SNVSAR0 – NOVEMBER 2016

www.ti.com

Product Folder Links: LM53602 LM53603

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Copyright © 2016, Texas Instruments Incorporated

8 Detailed Description

8.1 Overview

The LM5360x family of devices are synchronous current mode buck regulators designed specifically for the Wide

Input voltage Industrial and automotive market. The regulator automatically switches between PWM and PFM

depending on load. At heavy loads the device operates in PWM at a switching frequency of 2.1 MHz. The

regulator's oscillator can also be synchronized to an external system clock. At input voltages above about 20 V,

the switching frequency reduces to maintain regulation during conditions of abnormally high battery voltage. At

light loads the mode changes to PFM, with diode emulation allowing DCM. This reduces input supply current and

keeps the efficiency high. The user can also choose to lock the mode in PWM (FPWM) so that the switching

frequency remains constant regardless of load.

A RESET flag is provided to indicate when the output voltage is near its regulation point. This feature includes

filtering and a delay before asserting. This helps to prevent false flag operation during output voltage transients.

Note that, throughout this data sheet, references to the LM53603 apply equally to the LM53602. The difference

between the two devices is the maximum output current and specified MOSFET current limits.

8.2 Functional Block Diagram