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LM73605

ACTIVE

3.5V to 36V, 5A Synchronous Step-Down Voltage Converter

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Data sheet

A newer version of this product is available

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Same functionality with different pin-out to the compared device
LM61460 ACTIVE 3-V to 36-V, 6-A, Low-EMI synchronous step-down converter Smaller solution size, higher efficiency and lower EMI.
TPSM63608 ACTIVE High-density, 36-V input, 1-V to 20-V output, 6-A power module in 7.5-mm x 6.5-mm HotRod™ QFN Smaller design with an integrated-inductor power module.

LM73605

ACTIVE
Data sheet Order now

Product details

Rating Catalog Topology Buck Iout (max) (A) 5 Vin (max) (V) 36 Vin (min) (V) 3.5 Vout (max) (V) 34 Vout (min) (V) 1 Features Enable, Forced PWM, Frequency synchronization, Light Load Efficiency, Over Current Protection, Power good, Pre-Bias Start-Up, Soft Start Adjustable, Synchronous Rectification, Tracking, UVLO Fixed, Wettable flanks package Control mode current mode Operating temperature range (°C) -40 to 125 Iq (typ) (A) 0.000015 Duty cycle (max) (%) 96
Rating Catalog Topology Buck Iout (max) (A) 5 Vin (max) (V) 36 Vin (min) (V) 3.5 Vout (max) (V) 34 Vout (min) (V) 1 Features Enable, Forced PWM, Frequency synchronization, Light Load Efficiency, Over Current Protection, Power good, Pre-Bias Start-Up, Soft Start Adjustable, Synchronous Rectification, Tracking, UVLO Fixed, Wettable flanks package Control mode current mode Operating temperature range (°C) -40 to 125 Iq (typ) (A) 0.000015 Duty cycle (max) (%) 96
WQFN (RNP) 30 24 mm² 6 x 4
  • New product available: LM61460 60-V, 6-A synchronous converter
  • Synchronous rectification
  • Wettable flanks QFN package (WQFN)
  • Low quiescent current
    • 0.8 µA in shutdown (typical)
    • 15 µA in active mode with no load (typical)
  • Wide voltage conversion range:
    • tON-MIN = 60 ns (typical)
    • tOFF-MIN = 70 ns (typical)
  • Low MOSFET ON-resistance:
    • RDS_ON_HS = 53 mΩ (typical)
    • RDS_ON_LS = 31 mΩ (typical)
  • External bias input to improve efficiency
  • Pin-selectable auto mode or forced PWM operation
  • Adjustable frequency range: 350 kHz to 2.2 MHz
  • Synchronizable to external clock
  • Internal compensation
  • Power-good flag
  • Precision enable to program system UVLO
  • Flexible soft-start features:
    • Start-up into pre-biased load
    • Fixed or adjustable soft-start time
    • Output voltage tracking
  • Cycle-by-cycle current limiting
  • Short-circuit protection with hiccup mode
  • Create a custom design with the WEBENCH® power designer using LM73605 or LM73606
  • New product available: LM61460 60-V, 6-A synchronous converter
  • Synchronous rectification
  • Wettable flanks QFN package (WQFN)
  • Low quiescent current
    • 0.8 µA in shutdown (typical)
    • 15 µA in active mode with no load (typical)
  • Wide voltage conversion range:
    • tON-MIN = 60 ns (typical)
    • tOFF-MIN = 70 ns (typical)
  • Low MOSFET ON-resistance:
    • RDS_ON_HS = 53 mΩ (typical)
    • RDS_ON_LS = 31 mΩ (typical)
  • External bias input to improve efficiency
  • Pin-selectable auto mode or forced PWM operation
  • Adjustable frequency range: 350 kHz to 2.2 MHz
  • Synchronizable to external clock
  • Internal compensation
  • Power-good flag
  • Precision enable to program system UVLO
  • Flexible soft-start features:
    • Start-up into pre-biased load
    • Fixed or adjustable soft-start time
    • Output voltage tracking
  • Cycle-by-cycle current limiting
  • Short-circuit protection with hiccup mode
  • Create a custom design with the WEBENCH® power designer using LM73605 or LM73606

The LM73605 and LM73606 family of devices are easy-to-use synchronous step-down DC/DC converters capable of driving up to 5 A or 6 A of load current from a supply voltage ranging from 3.5 V to 36 V. The LM73605 and LM73606 provide exceptional efficiency and output accuracy in a very small solution size. Peak current-mode control is employed. Additional features such as adjustable switching frequency, synchronization to an external clock, power-good flag, precision enable, adjustable soft start, and tracking provide both flexible and easy-to-use solutions for a wide range of applications. Automatic frequency foldback at light load improves efficiency over the entire load range. Protection features include thermal shutdown, cycle-by-cycle current limiting, and short-circuit protection. The devices are pin-to-pin compatible for easy current scaling. The new product, LM61460-Q1, offers higher efficiency, lower stand-by quiescent current, and improved EMI performance. See the device comparison table to compare specifications. Start a Webench design with LM61460-Q1. Use the LMZM33606 module for faster time to market.

The LM73605 and LM73606 family of devices are easy-to-use synchronous step-down DC/DC converters capable of driving up to 5 A or 6 A of load current from a supply voltage ranging from 3.5 V to 36 V. The LM73605 and LM73606 provide exceptional efficiency and output accuracy in a very small solution size. Peak current-mode control is employed. Additional features such as adjustable switching frequency, synchronization to an external clock, power-good flag, precision enable, adjustable soft start, and tracking provide both flexible and easy-to-use solutions for a wide range of applications. Automatic frequency foldback at light load improves efficiency over the entire load range. Protection features include thermal shutdown, cycle-by-cycle current limiting, and short-circuit protection. The devices are pin-to-pin compatible for easy current scaling. The new product, LM61460-Q1, offers higher efficiency, lower stand-by quiescent current, and improved EMI performance. See the device comparison table to compare specifications. Start a Webench design with LM61460-Q1. Use the LMZM33606 module for faster time to market.
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Technical documentation

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Type Title Date
* Data sheet LM73605/LM73606 3.5-V to 36-V, 5-A or 6-A Synchronous Step-Down Voltage Converter datasheet (Rev. A) PDF | HTML 21 Jul 2017
Functional safety information LM73605 Functional Safety, FIT Rate, Failure Mode Distribution and Pin FMA PDF | HTML 12 Jul 2022
Application note Step-Dwn (Buck) Convrtr Pwer Solutions for Programmable Logic Controller Systems (Rev. A) PDF | HTML 26 Jul 2021
Selection guide Buck Converter Quick Reference Guide (Rev. B) 08 Apr 2021
Technical article How to add hysteresis to a DC/DC converter PDF | HTML 12 Nov 2018
Technical article Effects of IC package on EMI performance PDF | HTML 22 May 2018
Technical article Vary the output voltage in an inverting buck-boost topology PDF | HTML 12 Oct 2017
Application note Designing High Performance, Low-EMI, Automotive Power Supplies 30 Sep 2017

Design & development

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

Evaluation board

LM73605EVM-5V-2MHZ — LM73605 Synchronous Step-Down Converter Evaluation Module

The LM73605EVM-5V-2MHZ evaluation module (EVM) is a fully assembled and tested circuit for evaluating the LM73605 synchronous step-down voltage converter. The EVM operates from 6V to 36V input and provides a 5V output voltage with 5A maximum load current.
User guide: PDF
Not available on TI.com
Evaluation board

LM73605EVM-5V-400K — LM73605 Synchronous Step-Down Converter Evaluation Module

The LM73605EVM-5V-400K evaluation module (EVM) is a fully assembled and tested circuit for evaluating the LM73605 synchronous step-down voltage converter. The EVM operates from 6V to 36V input and provides a 5V output voltage with 5A maximum load current.

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

LM73605 Inverting and non-inverting PSpice Transient Model

SNVMBD7.ZIP (955 KB) - PSpice Model
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Simulation model

LM73605 TINA-TI Transient Reference Design

SNVMBE0.TSC (2316 KB) - TINA-TI Reference Design
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Simulation model

LM73605 TINA-TI Transient Spice Model

SNVMBE1.ZIP (79 KB) - TINA-TI Spice Model
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Simulation model

LM73605 Unencrypted PSpice Transient Model

SNVJ003.ZIP (9 KB) - Spice Model
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Simulation model

TINA-TI Enable Hysteresis Schematic

SNVMBL7.ZIP (4 KB) - TINA-TI Reference Design
Download
Calculation tool

SNVR524 — LM73605 Quickstart Tool

Supported products & hardware

Supported products & hardware

Products
DC/DC converters
  • LM73605 — 3.5V to 36V, 5A Synchronous Step-Down Voltage Converter
  • LM73605-Q1 — Automotive qualified 3.5-V to 36-V, 5-A synchronous step-down voltage converter
  • LM73606 — 3.5V to 36V, 6A Synchronous Step-Down Voltage Converter
  • LM73606-Q1 — Automotive qualified 3.5-V to 36-V, 6-A synchronous step-down voltage converter
Download
Gerber file

DC/DC Converter Enable Hysteresis Calculator

SNVC227.ZIP (40 KB)
Download
Reference designs

TIDA-01458 — Low-Noise Fixed Drop-Out ±2.5 to ±12-VOUT 3A Power Supply Reference Design for Ultrasound CW Pulser

This reference design allows a digitally programmable power supply to power an ultrasound transmit circuit for continuous wave (CW) mode from a 24-V bus. There are two outputs adjustable from ±2.5 to ±12 V under user software control. These outputs can provide up to 2 A with very low (...)
Design guide: PDF
Schematic: PDF
Reference designs

TIDA-010011 — High efficiency power supply architecture reference design for protection relay processor module

This reference design showcases various power architectures for generating multiple voltage rails for an application processor module, requiring >1A load current and high efficiency . The required power supply is generated using 5-, 12- or 24-V DC input from the backplane. Power supplies are (...)
Design guide: PDF
Schematic: PDF
Package Pins CAD symbols, footprints & 3D models
WQFN (RNP) 30 Ultra Librarian
TI's Standard Terms and Conditions for Evaluation Items apply.

Ordering & quality

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  • Lead finish/Ball material
  • MSL rating/Peak reflow
  • MTBF/FIT estimates
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  • Qualification summary
  • Ongoing reliability monitoring
Information included:
  • Fab location
  • Assembly location

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