+

-

+

-

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

1.0V

Reference

ENABLE

LOGIC

10

LM53602-Q1, LM53603-Q1

SNVSA42B – JUNE 2015 – REVISED MAY 2016

www.ti.com

Product Folder Links: LM53602-Q1 LM53603-Q1

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Copyright © 2015–2016, Texas Instruments Incorporated

8 Detailed Description

8.1 Overview

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

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.

Please note that, throughout this data sheet, references to the LM53603-Q1 apply equally to the LM53602-Q1.

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

8.2 Functional Block Diagram