LTC3126

RECOMMENDED FOR NEW DESIGNS

42V, 2.5A Synchronous Step-Down Regulator with No-Loss Input PowerPath

Part Models: 12
1ku List Price: Starting From $4.65

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Overview

Seamless, Automatic Transition Between Two Input Power Sources
Wide Input Voltage Range: 2.4V to 42V
Wide Output Voltage Range: 0.818V to V_IN
Up to 2.5A Continuous Output Current
Pin Selectable Priority and Ideal Diode-OR Modes
Burst Mode^® Operation, I_Q = 2μA
95% Efficiency at 1A, V_IN = 12V, V_OUT = 5V
1μA Current in Shutdown
Programmable Input UVLO Thresholds
Input Valid, Priority Channel and PGOOD Indicators
200kHz to 2.2MHz Fixed Frequency PWM
Synchronizable to an External Clock
Current Mode Control with 60ns Minimum On-Time
Minimal External Components
Thermally Enhanced 28-Lead 4mm × 5mm QFN and 28-Lead TSSOP Packages

The LTC3126 is a high efficiency synchronous buck converter with an internal no-loss PowerPath^™ supporting seamless operation from two separate input power sources. Pin selectable ideal diode-OR and priority input modes with user programmable undervoltage lockout thresholds provide full control over the transition between the input power sources. The fast, automatic switchover provided by the internal PowerPath eliminates the need for hold-up capacitors and minimizes disturbances on the output rail. An active input channel indicator and independent input and output power good signals provide complete feedback of the power system status.

A wide 2.4V to 42V input voltage range, 2.5A output current capability and 2μA Burst Mode operation quiescent current facilitate use of the LTC3126 with a wide variety of power sources including supercapacitors, automotive batteries, unregulated wall adapters and single to multicell stacks of most battery chemistries. Additional features include 1μA current in shutdown, internal soft-start and thermal protection. The LTC3126 is available in thermally enhanced 28-lead 4mm × 5mm QFN and 28-lead TSSOP packages.

Applications

Portable Industrial/Communications Test Equipment
Battery and Supercapacitor Backup Power
Automotive Power with Battery Backup
Uninterruptible Power Supplies

Part Models: 12
1ku List Price: Starting From $4.65

Documentation

ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal. View our quality and reliability program and certifications for more information.

Part Model	Pin/Package Drawing	Documentation	CAD Symbols, Footprints, and 3D Models
LTC3126EFE#PBF	28-Lead TSSOP w/ EP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC3126EFE#TRPBF	28-Lead TSSOP w/ EP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC3126EUFD#PBF	28-Lead QFN (4mm x 5mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC3126EUFD#TRPBF	28-Lead QFN (4mm x 5mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC3126HFE#PBF	28-Lead TSSOP w/ EP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC3126HFE#TRPBF	28-Lead TSSOP w/ EP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC3126IFE#PBF	28-Lead TSSOP w/ EP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC3126IFE#TRPBF	28-Lead TSSOP w/ EP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC3126IUFD#PBF	28-Lead QFN (4mm x 5mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC3126IUFD#TRPBF	28-Lead QFN (4mm x 5mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC3126MPFE#PBF	28-Lead TSSOP w/ EP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC3126MPFE#TRPBF	28-Lead TSSOP w/ EP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys

Part Models	Product Lifecycle	PCN

Apr 6, 2022 - 22_0068 Laser Top Mark for ETSSOP and TSSOP Packages Assembled in ADPG [PNG] and UTL
		PCN22_0068_Form Material_Report Delta Qualification Matrix
LTC3126EFE#PBF	PRODUCTION
LTC3126EFE#TRPBF	PRODUCTION
LTC3126HFE#PBF	PRODUCTION
LTC3126HFE#TRPBF	PRODUCTION
LTC3126IFE#PBF	PRODUCTION
LTC3126IFE#TRPBF	PRODUCTION
LTC3126MPFE#PBF	PRODUCTION
LTC3126MPFE#TRPBF	PRODUCTION
Apr 11, 2019 - 19_0067 Notification of Wafer Fab Location Change for 0.35 BCD Process
		PCN19_0067_Form Material_Report Delta Qualification Matrix Qualification Results Summary Detailed Parts List Other
LTC3126EFE#PBF	PRODUCTION
LTC3126EFE#TRPBF	PRODUCTION
LTC3126EUFD#PBF	PRODUCTION
LTC3126EUFD#TRPBF	PRODUCTION
LTC3126HFE#PBF	PRODUCTION
LTC3126HFE#TRPBF	PRODUCTION
LTC3126IFE#PBF	PRODUCTION
LTC3126IFE#TRPBF	PRODUCTION
LTC3126IUFD#PBF	PRODUCTION
LTC3126IUFD#TRPBF	PRODUCTION
Feb 20, 2022 - 21_0269 Addition of Alternate Assembly Site ASE Taiwan for Select LFCSP Products
		PCN21_0269_Form Material_Report Detailed Change Description Qualification Results Summary
LTC3126EUFD#PBF	PRODUCTION
LTC3126EUFD#TRPBF	PRODUCTION
LTC3126IUFD#PBF	PRODUCTION
LTC3126IUFD#TRPBF	PRODUCTION

This is the most up-to-date revision of the Data Sheet.

Software Resources

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Hardware Ecosystem

Parts	Product Life Cycle	Description
Protection Switches & Controllers 2
LTC4417	RECOMMENDED FOR NEW DESIGNS	Prioritized PowerPath^™ Controller
LTC4419	RECOMMENDED FOR NEW DESIGNS	18V Dual Input Micropower PowerPath Prioritizer

Parts	Product Life Cycle	Description
LTC3118	RECOMMENDED FOR NEW DESIGNS	18V, 2A Buck-Boost DC/DC Converter with Low-Loss Dual Input PowerPath

Tools & Simulations

LTspice

Models for the following parts are available in LTspice:

LTC3126

LTpowerCAD

Design tools for the following parts are available in LTpowerCAD:

LTC3126

LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.

Evaluation Kits

LTC3126EUFD Demo Board | Dual Input Sync Buck, 4.3V ≤ VIN1 ≤ 42V, 6V ≤ VIN2 ≤ 8.4V (Operational to 42V), VOUT = 3.3V @ 2.5A

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Product Details

Demonstration Circuit 2215A, features the LTC3126, a synchronous buck converter with an integrated lossless input PowerPath™. Pin selectable (JP2) ideal diode-OR and priority input modes, with programmable undervoltage lockout thresholds provide control over the transition between input sources. The unique all N-channel architecture provides efficient operation from either of two input sources to a programmable output voltage. In this application the valid input voltage range is set to be from 4.3V to 42V on V_IN1 and from 6V to 8.4V on V_IN2 providing flexibility and voltage margin for a variety of applications and power sources. V_IN2 can operate to 42V. Other input voltage ranges are possible by adjusting the V_SET1/2 threshold values (set by resistors R9 thru R12) accordingly.