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) (uA) 27 Switching frequency (Min) (kHz) 200 Switching frequency (Max) (kHz) 2200 Features Enable, Frequency Synchronization, Light Load Efficiency, Over Current Protection, Power Good, Synchronous Rectification, Tracking Rating Catalog Regulated outputs (#) 1 Control mode Current Mode Duty cycle (Max) (%) 99
Vin (Min) (V) 3.5 Vin (Max) (V) 36 Vout (Min) (V) 1 Vout (Max) (V) 28 Iout (Max) (A) 3 Iq (Typ) (uA) 27 Switching frequency (Min) (kHz) 200 Switching frequency (Max) (kHz) 2200 Features Enable, Frequency Synchronization, Light Load Efficiency, Over Current Protection, Power Good, Synchronous Rectification, Tracking Rating Catalog Regulated outputs (#) 1 Control mode Current Mode Duty cycle (Max) (%) 99
HTSSOP (PWP) 16 32 mm² 5 x 6.4 VSON (DSU) 16 20 mm² 5 x 4
  • 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 with the WEBENCH® Power Designer
  • 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 with the WEBENCH® Power Designer

The LM43603 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 abs max). The LM43603 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 device is available in the HTSSOP / PWP 16 leaded package (5.1 mm × 6.6 mm × 1.2 mm) and VSON-16 package with wettable flanks. HTSSOP package is pin-to-pin compatible with LM43600, LM43601, LM43602, LM46000, LM46001, LM46002. VSON-16 package is only pin-to-pin compatible with LM43602.

The LM43603 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 abs max). The LM43603 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 device is available in the HTSSOP / PWP 16 leaded package (5.1 mm × 6.6 mm × 1.2 mm) and VSON-16 package with wettable flanks. HTSSOP package is pin-to-pin compatible with LM43600, LM43601, LM43602, LM46000, LM46001, LM46002. VSON-16 package is only pin-to-pin compatible with LM43602.

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Technical documentation

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Type Title Date
* Data sheet LM43603 3.5-V to 36-V, 3A Synchronous Step-Down Voltage Converter datasheet (Rev. D) PDF | HTML 08 Aug 2017
Technical article Minimize the impact of the MLCC shortage on your power application 29 Mar 2019
Application note Understanding Inverting Buck-Boost Power Stages in Switch Mode Power Supplies (Rev. B) 12 Mar 2019
Application note Differences Between LM4600x/LM4360x A and Non-A OPNs 27 Mar 2018
White paper Synchronous Rectification in High-Performance Power Converter Design (Rev. A) 15 Sep 2016
Technical article Quantifying the value of wide VIN 15 Jun 2016
Technical article DC/DC converter datasheets – System losses demystified 25 Apr 2016
Application note Semiconductor and IC Package Thermal Metrics (Rev. C) PDF | HTML 19 Apr 2016
Technical article DC/DC converter datasheets - Quiescent current demystified: Part two 11 Apr 2016
EVM User's guide LM43603DSU EVM User Guide 16 Mar 2016
More literature SIMPLE SWITCHER Synchronous Regulator Series (Rev. B) 08 Feb 2016
Application note Know Your Limits 02 Jun 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
EVM User's guide LM43603EVM User’s Guide 18 Feb 2014
Application note AN-1533 Overvoltage Protection Circuit for Automotive Load Dump (Rev. B) 06 May 2013
Application note AN-1997 Error Amplifier Limitations in High-Performance Regulator Applications (Rev. A) 06 May 2013
Application note AN-2162 Simple Success With Conducted EMI From DC-DC Converters (Rev. C) 24 Apr 2013
Application note AN-1149 Layout Guidelines for Switching Power Supplies (Rev. C) 23 Apr 2013
Application note AN-1197 Selecting Inductors for Buck Converters (Rev. B) 23 Apr 2013
Application note AN-1229 SIMPLE SWITCHER PCB Layout Guidelines (Rev. C) 23 Apr 2013
Application note AN-1520 A Guide to Board Layout for Best Thermal Resistance for Exposed Packages (Rev. B) 23 Apr 2013
Application note AN-1566 Techniques for Thermal Analysis of Switching Power Supply Designs (Rev. A) 23 Apr 2013
Application note AN-1889 How to Measure the Loop Transfer Function of Power Supplies (Rev. A) 23 Apr 2013
Application note AN-2155 Layout Tips for EMI Reduction in DC/ DC Converters (Rev. A) 23 Apr 2013
Application note Understanding and Applying Current-Mode Control Theory 19 Aug 2007
Application note Input and Output Capacitor Selection 19 Sep 2005
More literature SEM1600 Topic 4: Constructing Your Power Supply – Layout Considerations 12 Jul 2005
Application note AN-643 EMI/RFI Board Design (Rev. B) 03 May 2004

Design & development

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

Evaluation board

LM43603DSUEVM — LM43603DSU Synchronous Step-Down Converter Evaluation Module

The LM43603DSUEVM evaluation module (EVM) is a fully assembled and tested circuit for evaluating the LM43603DSU synchronous step-down converter. The EVM operates from a 3.5V to 36V input and provides a 5V output at 3A.
User guide: PDF
Not available on TI.com
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 PSpice Average Model

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

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

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

LM43603 TINA-TI Transient Spice Model

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

LM43603 TINA-TI Transient Reference Design

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

PMP30046 — Enterprise SSD Backup Power Reference Design

The PMP30046 reference design shows a system solution for an enterprise SSD backup power supply. The input voltage of the hotswap controller can be either 5V or 12V. A buck stage converts this input voltage to 3.3V with a maximum load current of 2.5A. The 3.3V are boosted to 28V for charging a (...)
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.
Schematic: PDF
Reference designs

PMP9454 — Synchronous Upgrade to Plug In Power Module Reference Design

The PMP9454 reference design is footprint compatible to the  module PTN78060W.  The PMP9454 reference design is an easy to use synchronous regulator with LM43603 SIMPLE SWITCHER stepdown DC-DC converter.  PMP9454 is capable of driving up to 3A load current from a wide input voltage (...)
Schematic: PDF
Reference designs

PMP9462 — Wide Vin Low Noise Triple Output Step Down Converter Reference Design

The reference design PMP9462 is a single input step-down converter with three low-noise outputs. The module uses LM43603, a synchronous step-down DC-DC converter capable of driving up to 3A of load current from an input voltage ranging 7V to 36V. The 5V output from LM43603 enables the LM26420 which (...)
Schematic: PDF
Package Pins Download
HTSSOP (PWP) 16 View options
SON (DSU) 16 View options

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