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LM43603-Q1

ACTIVE

Automotive Qualified 3.5V to 36V, 3A Synchronous Step-Down Voltage Converter

A newer version of this product is available

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Product details

Vin (min) (V) 3.5 Vin (max) (V) 36 Vout (min) (V) 1 Vout (max) (V) 28 Iout (max) (A) 3 Iq (typ) (mA) 0.027 Switching frequency (min) (kHz) 200 Switching frequency (max) (kHz) 2200 Features Enable, Frequency synchronization, Light Load Efficiency, Over Current Protection, Power good, Pre-Bias Start-Up, Soft Start Adjustable, Synchronous Rectification, Tracking Operating temperature range (°C) -40 to 125 Rating Automotive Regulated outputs (#) 1 Control mode current mode Duty cycle (max) (%) 99 Type Converter
Vin (min) (V) 3.5 Vin (max) (V) 36 Vout (min) (V) 1 Vout (max) (V) 28 Iout (max) (A) 3 Iq (typ) (mA) 0.027 Switching frequency (min) (kHz) 200 Switching frequency (max) (kHz) 2200 Features Enable, Frequency synchronization, Light Load Efficiency, Over Current Protection, Power good, Pre-Bias Start-Up, Soft Start Adjustable, Synchronous Rectification, Tracking Operating temperature range (°C) -40 to 125 Rating Automotive Regulated outputs (#) 1 Control mode current mode Duty cycle (max) (%) 99 Type Converter
HTSSOP (PWP) 16 32 mm² 5 x 6.4
  • Qualified for Automotive Applications
  • AEC-Q100 Qualified With the Following Results:
    • Device Temperature Grade 1: –40°C to +125°C Operating Junction Temperature
  • 27-µA Quiescent Current in Regulation
  • High Efficiency at Light Load (DCM and PFM)
  • Meets EN55022/CISPR 22 EMI Standards
  • Integrated Synchronous Rectification
  • Adjustable Frequency Range: 200 kHz to 2.2 MHz (500 kHz default)
  • Frequency Synchronization to External Clock
  • Internal Compensation
  • Stable With Almost any Combination of Ceramic, Polymer, Tantalum, and Aluminum Capacitors
  • Power-Good Flag
  • Soft Start into a Pre-Biased Load
  • Internal Soft Start: 4.1 ms
  • Extendable Soft-Start Time by External Capacitor
  • Output Voltage Tracking Capability
  • Precision Enable to a Program System UVLO
  • Output Short Circuit Protection with Hiccup Mode
  • Overtemperature Thermal Shutdown Protection
  • Create a Custom Design Using the LM43603-Q1 With the WEBENCH® Power Designer
  • Qualified for Automotive Applications
  • AEC-Q100 Qualified With the Following Results:
    • Device Temperature Grade 1: –40°C to +125°C Operating Junction Temperature
  • 27-µA Quiescent Current in Regulation
  • High Efficiency at Light Load (DCM and PFM)
  • Meets EN55022/CISPR 22 EMI Standards
  • Integrated Synchronous Rectification
  • Adjustable Frequency Range: 200 kHz to 2.2 MHz (500 kHz default)
  • Frequency Synchronization to External Clock
  • Internal Compensation
  • Stable With Almost any Combination of Ceramic, Polymer, Tantalum, and Aluminum Capacitors
  • Power-Good Flag
  • Soft Start into a Pre-Biased Load
  • Internal Soft Start: 4.1 ms
  • Extendable Soft-Start Time by External Capacitor
  • Output Voltage Tracking Capability
  • Precision Enable to a Program System UVLO
  • Output Short Circuit Protection with Hiccup Mode
  • Overtemperature Thermal Shutdown Protection
  • Create a Custom Design Using the LM43603-Q1 With the WEBENCH® Power Designer

The LM43603-Q1 regulator is an easy-to-use synchronous step-down DC-DC converter capable of driving up to 3 A of load current from an input voltage ranging from 3.5 V to 36 V (42 V absolute maximum). The LM43603-Q1 provides exceptional efficiency, output accuracy, and dropout voltage in a very small solution size. An extended family is available in 0.5-A, 1-A, and 2-A load current options in pin-to-pin compatible packages. Peak current mode control is employed to achieve simple control loop compensation and cycle-by-cycle current limiting. Optional features such as programmable switching frequency, synchronization, power-good flag, precision enable, internal soft-start, extendable soft start, and tracking provide a flexible and easy to use platform for a wide range of applications. Discontinuous conduction and automatic frequency modulation at light loads improve light load efficiency. The family requires few external components and pin arrangement allows simple, optimum PCB layout. Protection features include thermal shutdown, VCC undervoltage lockout, cycle-by-cycle current limit, and output short circuit protection. The LM43603-Q1 device is available in the HTSSOP (PWP) 16-pin leaded package (6.6 mm × 5.1 mm × 1.2 mm). The LM43603A-Q1 version is optimized for PFM operation and recommended for new design. The device is pin-to-pin compatible with LM4360x and LM4600x family.

The LM43603-Q1 regulator is an easy-to-use synchronous step-down DC-DC converter capable of driving up to 3 A of load current from an input voltage ranging from 3.5 V to 36 V (42 V absolute maximum). The LM43603-Q1 provides exceptional efficiency, output accuracy, and dropout voltage in a very small solution size. An extended family is available in 0.5-A, 1-A, and 2-A load current options in pin-to-pin compatible packages. Peak current mode control is employed to achieve simple control loop compensation and cycle-by-cycle current limiting. Optional features such as programmable switching frequency, synchronization, power-good flag, precision enable, internal soft-start, extendable soft start, and tracking provide a flexible and easy to use platform for a wide range of applications. Discontinuous conduction and automatic frequency modulation at light loads improve light load efficiency. The family requires few external components and pin arrangement allows simple, optimum PCB layout. Protection features include thermal shutdown, VCC undervoltage lockout, cycle-by-cycle current limit, and output short circuit protection. The LM43603-Q1 device is available in the HTSSOP (PWP) 16-pin leaded package (6.6 mm × 5.1 mm × 1.2 mm). The LM43603A-Q1 version is optimized for PFM operation and recommended for new design. The device is pin-to-pin compatible with LM4360x and LM4600x family.

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Technical documentation

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Type Title Date
* Data sheet LM43603-Q1 3.5-V to 36-V, 3-A Synchronous Step-Down Voltage Converter datasheet (Rev. C) PDF | HTML 20 Oct 2017
Application note Differences Between LM4600x/LM4360x A and Non-A OPNs 27 Mar 2018
Technical article A complete low-voltage backup battery solution for eCall systems PDF | HTML 05 Mar 2016
Technical article Overcoming automotive cluster power supply design challenges PDF | HTML 13 Nov 2015
Application note Inverting Applications Made SIMPLE With LM4600x and LM4360x (Rev. B) 20 Feb 2015
Application note Thermal Design Made Simple With LM43603 and LM46002 15 Sep 2014
Application note Low EMI Layout Made SIMPLE With LM43600/1/2/3 and LM46000/1/2 (Rev. A) 12 Sep 2014
Application note Compensation Made SIMPLE With LM4360x, LM4600x 29 Jul 2014
Application note Automotive Line Transient Protection Circuit 01 Jul 2014
Application note AN-1197 Selecting Inductors for Buck Converters (Rev. B) 23 Apr 2013

Design & development

For additional terms or required resources, click any title below to view the detail page where available.

Evaluation board

LM43603PWPEVM — LM43603PWP Synchronous Step-Down Converter Evaluation Module

The LM43603PWPEVM evaluation module (EVM) is a fully assembled and tested circuit for evaluating the LM43603PWP synchronous step-down converter. The EVM operates from an 3.5V to 36V input and provides a 3.3V output at 3A.

User guide: PDF
Not available on TI.com
Simulation model

LM43603 Non-Inverting and Inverting PSpice Transient Model (Rev. A)

SNVM585A.ZIP (525 KB) - PSpice Model
Simulation model

LM43603 PSpice Average Model

SNVM572.ZIP (76 KB) - PSpice Model
Simulation model

LM43603 TINA-TI Transient Reference Design

SNVM609.TSC (88 KB) - TINA-TI Reference Design
Simulation model

LM43603 TINA-TI Transient Spice Model

SNVM605.ZIP (52 KB) - TINA-TI Spice Model
Simulation model

LM43603 Unencrypted PSpice Average Model

SNVM724.ZIP (1 KB) - PSpice Model
Simulation tool

PSPICE-FOR-TI — PSpice® for TI design and simulation tool

PSpice® for TI is a design and simulation environment that helps evaluate functionality of analog circuits. This full-featured, design and simulation suite uses an analog analysis engine from Cadence®. Available at no cost, PSpice for TI includes one of the largest model libraries in the (...)
Reference designs

PMP10735 — Wide Vin, 3A Buck 2-Layer Reference Design for Automotive Cluster with CISPR 25 Class 5 Compliance

The PMP10735 reference design is a 5V, 3A output power supply in a 2-layer board design for off-battery automotive instrument cluster applications. The reference board has an input EMI filter and optmized layout for improved EMI performance.
Test report: PDF
Schematic: PDF
Reference designs

PMP9769 — Automotive eCall Power Supply Reference Design with Low Intermediate Voltage

This reference design includes a complete power management solution for a standalone emergency call (eCall) system in an automotive environment. The circuit is supplied directly from the car battery rail. It also manages a backup battery to power the eCall system while the car battery rail is not (...)
Test report: PDF
Schematic: PDF
Reference designs

PMP9080 — Automotive Single-port USB Charging featuring LM43603 and TPS2543 Reference Design

Compact design for automotive single-port USB charging featuring the new synchronous 36V, 3A LM43603 SIMPLE SWITCHER and the TPS2543 USB Switch and Controller. LM2904 is used to provide cable droop compensation.
Test report: PDF
Schematic: PDF
Package Pins Download
HTSSOP (PWP) 16 View options

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