LTC1871X - Wide Input Range, No RSENSE Current Mode Boost, Flyback and SEPIC Controller

Features

  • 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
  • ±2% Internal Voltage Reference
  • Micropower Shutdown: IQ = 10μA
  • Programmable Operating Frequency (65kHz to 900kHz) with One External Resistor
  • Synchronizable to an External Clock Up to 1.3 × fOSC
  • 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

Typical Application

LTC1871X Typical Application
LTC1871X Typical Application

Description

LTC®1871X is a wide input range, current mode, boost, flyback or SEPIC controller that drives an N-channel power MOSFET. LTC1871X is rated to 175°C junction temperature and is 100% tested at 175°C. 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 65kHz to 900kHz 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 LTC1871X 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 LTC1871X by connecting the SENSE pin to a resistor in the source of the power MOSFET. The LTC1871X 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

Packaging

For complete and up to date package information and drawings, please refer to our packaging page

Part Number Package Code Temp Package
Drawing
RoHS
LTC1871XMS#PBF MS-10 MS X 05-08-1661 Yes
LTC1871XMS#TRPBF MS-10 MS X 05-08-1661 Yes


LTC1871X Package Drawing

Order Info

  • Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
  • Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
  • Please refer to our general ordering information or the product datasheet for more details

Package Variations and Pricing

Part Number Package Temp Price
(1-99)
Price
(1k)*
RoHS
LTC1871XMS#PBF MS-10 X $178.57 $125.00 Yes
LTC1871XMS#TRPBF MS-10 X $178.63 $125.06 Yes
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* The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Linear Technology sales office or authorized distributor.

Demo Boards

Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.

Click here to view our complete list of demo boards

Applications

  • Telecom Power Supplies
  • Portable Electronic Equipment

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Design Tools

LTspice

LTspice® software is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. Click here to download LTspice

Models for the following parts are available in LTspice:
LTC1871
LTC1871-1
LTC1871-7

Technical Support