LTC1871-1

PRODUCTION

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

Part Models: 4
1ku List Price: Starting From $3.19

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Part Details

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
Ultra Low Pulse Skip Threshold for Wide Input Range Applications
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 LTC1871-1 is a wide input range, current mode, boost, flyback or SEPIC controller that drives an Nchannel power MOSFET and requires very few external components. It eliminates the need for a current sense resistor by utilizing the power MOSFET’s on-resistance, thereby maximizing efficiency. Higher output voltage applications are possible with the LTC1871-1 by connecting the SENSE pin to a resistor in the source of the power MOSFET.

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.

The LTC1871-1 differs from the LTC1871 by having a lower pulse skip threshold, making it ideal for applications requiring constant frequency operation at light loads. The lower pulse skip threshold also helps maintain constant frequency operation in applications with a wide input voltage range. For applications requiring primary-to-secondary side isolation, please refer to the LTC1871 datasheet.

The LTC1871-1 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: 4
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-1#PBF	10-Lead MSOP	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LTC1871EMS-1#TRPBF	10-Lead MSOP	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LTC1871IMS-1#PBF	10-Lead MSOP	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LTC1871IMS-1#TRPBF	10-Lead MSOP	Material Declaration Reliablity Data	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-1#PBF	PRODUCTION
LTC1871EMS-1#TRPBF	PRODUCTION
LTC1871IMS-1#PBF	PRODUCTION
LTC1871IMS-1#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-1#PBF	PRODUCTION
LTC1871EMS-1#TRPBF	PRODUCTION
LTC1871IMS-1#PBF	PRODUCTION
LTC1871IMS-1#TRPBF	PRODUCTION

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

Hardware Ecosystem

Parts	Product Life Cycle	Description
Silicon 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

LTC1871-1 Demo Circuit - High Efficiency SEPIC Converter (4.5-15V 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-1 Demo Board | SEPIC Controller; 5V to 20 VIN, 12 VOUT @ 3A

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Product Details

Demonstration circuit 1225 is high efficiency nonisolated SEPIC (Single Ended Primary Inductor Converter) converter featuring the LTC1871-1 switching controller. The DC1225 converts 5V to 20V input to 12V output and provides over 3A of output current. The converter operates at 300kHz with efficiency over 94%. With proper amount of airflow, the DC1225 converter can generate over 3A of output current. The DC1225 can be easily modified to generate output voltages in the range from 1.23V to 48V. Also, the DC1225 can be modified for other input voltages like 5V-36V, 9V-36V, 36V-72V, and so on. The wider input voltage range will decrease the converter efficiency.

Resources

DC1225A - Design File
765.00K

DC1225A - Demo Manual
647.00K

DC1225A - Schematic
32.00K

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