LTC1871

PRODUCTION

Wide Input Range, No R_SENSE^™ Current Mode Boost, Flyback and SEPIC Controller

Part Models: 7
1ku List Price: Starting From $3.19

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Overview

High Efficiency (No Sense Resistor Required)
Wide Input Voltage Range: 2.5V to 36V
Current Mode Control Provides Excellent Transient Response
High Maximum Duty Cycle (92% Typ)
±2% RUN Pin Threshold with 100mV Hysteresis
±1% Internal Voltage Reference
Micropower Shutdown: I_Q = 10μA
Programmable Operating Frequency (50kHz to 1MHz) with One External Resistor

Synchronizable to an External Clock Up to 1.3 × f_OSC
User-Controlled Pulse Skip or Burst Mode^® Operation
Internal 5.2V Low Dropout Voltage Regulator
Output Overvoltage Protection
Capable of Operating with a Sense Resistor for High Output Voltage Applications
Small 10-Lead MSOP Package

The LTC1871 is a wide input range, current mode, boost, flyback or SEPIC controller that drives an N-channel power MOSFET and requires very few external components. Intended for low to medium power applications, it eliminates the need for a current sense resistor by utilizing the power MOSFET’s on-resistance, thereby maximizing efficiency.

The IC’s operating frequency can be set with an external resistor over a 50kHz to 1MHz range, and can be synchronized to an external clock using the MODE/SYNC pin. Burst Mode operation at light loads, a low minimum operating supply voltage of 2.5V and a low shutdown quiescent current of 10μA make the LTC1871 ideally suited for battery-operated systems.

For applications requiring constant frequency operation, Burst Mode operation can be defeated using the MODE/ SYNC pin. Higher output voltage boost, SEPIC and flyback applications are possible with the LTC1871 by connecting the SENSE pin to a resistor in the source of the power MOSFET.

The LTC1871 is available in the 10-lead MSOP package.


	Vin Range	INTVcc	Features
LTC1871	2.5V to 36V	5.2V	-
LTC1871-1	2.5V to 36V	5.2V	Lower Burst Mode Threshold (0.195V vs. 0.3V)
LTC1871-7	6V to 36V	7V	Drives 6V Gate N-Channel MOSFETs
LTC1871X	2.5V to 36V	5.2V	175°C Junction Temp, 100% Tested at 175°C

Applications

Telecom Power Supplies
Portable Electronic Equipment

Part Models: 7
1ku List Price: Starting From $3.19

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
LTC1871EMS#PBF	10-Lead MSOP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC1871EMS#TR	10-Lead MSOP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC1871EMS#TRPBF	10-Lead MSOP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC1871HMS#PBF	10-Lead MSOP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC1871HMS#TRPBF	10-Lead MSOP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC1871IMS#PBF	10-Lead MSOP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC1871IMS#TRPBF	10-Lead MSOP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys

Part Models	Product Lifecycle	PCN

Jun 5, 2024 - 24_0004 Epoxy Change from Henkel 8290 to 8290A for MSOP (3)
		PCN24_0004_Form Material_Report Qualification Results Summary Delta Qualification Matrix
LTC1871EMS#PBF	PRODUCTION
LTC1871EMS#TRPBF	PRODUCTION
LTC1871IMS#PBF	PRODUCTION
LTC1871IMS#TRPBF	PRODUCTION
Feb 4, 2020 - 20_0130 Laser Top Mark Conversion for 10-Lead MSOP Packages Assembled in ADPG and UTAC
		PCN20_0130_Form Material_Report
LTC1871EMS#PBF	PRODUCTION
LTC1871EMS#TR	LAST TIME BUY
LTC1871EMS#TRPBF	PRODUCTION
LTC1871HMS#PBF	PRODUCTION
LTC1871HMS#TRPBF	PRODUCTION
LTC1871IMS#PBF	PRODUCTION
LTC1871IMS#TRPBF	PRODUCTION
Oct 11, 2022 - 22_0244 Epoxy Change from Henkel 8290 to 8290A for MSOP Package
		PCN22_0244_Form Material_Report Qualification Results Summary Delta Qualification Matrix
LTC1871EMS#TR	LAST TIME BUY
LTC1871HMS#PBF	PRODUCTION
LTC1871HMS#TRPBF	PRODUCTION
Jul 12, 2022 - 22_0157 UTAC Thai Limited (UTL) as Alternate Assembly Site for MSOP Packages [With Modification in BOM]
		PCN22_0157_Form Material_Report Qualification Results Summary Delta Qualification Matrix Detailed Parts List
LTC1871HMS#PBF	PRODUCTION
LTC1871HMS#TRPBF	PRODUCTION
Jun 21, 2022 - 22_0050 UTAC Thai Limited (UTL) as Alternate Assembly Site for MSOP Packages / Devices
		PCN22_0050_Form Material_Report Qualification Results Summary Delta Qualification Matrix
LTC1871HMS#PBF	PRODUCTION
LTC1871HMS#TRPBF	PRODUCTION
May 29, 2025 - 25_0024 Carsem SnPb Packaging End of Life
		PDN25_0024_Form Material_Report
LTC1871EMS#TR	LAST TIME BUY	PDN25_0024_Form Material_Report
Aug 16, 2021 - 20_0040 Discontinuation of Lead Finished Parts for MSOP Package.
		PDN20_0040_Form Material_Report
LTC1871EMS#TR	LAST TIME BUY	PDN20_0040_Form Material_Report

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
Oscillators 2
LTC6908		Resistor Set SOT-23 Oscillator with Spread Spectrum Modulation
LTC6909	PRODUCTION	1 to 8 Output, Multiphase Silicon Oscillator with Spread Spectrum Modulation

Tools & Simulations

LTspice 1

LTC1871 Demo Circuit - 2A Wide Input, SEPIC DC/DC Converter (5-15V to 12V @ 2A)

Models for the following parts are available in LTspice:

LTC1871
LTC1871-1
LTC1871-7

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

LTC1871EMS | Boost Controller, 3V ≤ VIN ≤ 5V, VOUT = 5V @ 7A

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Product Details

Demonstration circuit DC414 is a step-up (Boost) DC-DC converter featuring the LTC1871 controller. The circuit is capable of providing an output voltage of 5V at 7A (10A peak) from an input supply of 3.3V. External frequency synchronization is provided, as are two modes of operation at light load conditions: Burst mode™ operation to reduce switching losses and maintain high operating efficiency, and continuous mode to provide constant operating frequency with low quiescent current. The LTC1871 is a No R_SENSE^™ current mode step-up controller. It eliminates the need for a current sense resistor and maximizes the efficiency of the demo circuit —up to 95%. The LTC1871 can operate up to a frequency of 1MHz, allowing for the use of small inductors and capacitors. The low shutdown quiescent current of 10μA makes the LTC1871 ideally suited for battery-operated systems. Applications include telecom power supplies, cellular phones, PDAs and portable electronic equipment.

Resources

DC414B - Design Files
8/31/2015

DC414B - Demo Manual
8/31/2015

DC414B - Schematic
8/31/2015

LTC1871EMS | High Efficiency SEPIC Converter, 5V-15V Input, 12VOUT @ 2Amp

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Product Details

Demonstration circuit 415 is a SEPIC (step-up or step-down) DC/DC converter featuring the LTC1871 controller. The circuit is capable of providing an output voltage of 12V at 2A from an input voltage of 5V to 15V. External frequency synchronization is provided, as are two modes of operation at light load conditions: Burst Mode^® operation reduces switching losses and maintains high efficiency operation; and continuous mode which provides constant operating frequency with low quiescent current.