LTC3873 - No RSENSE Constant Frequency Current Mode Boost/Flyback/SEPIC DC/DC Controller

The LTC3873 is a constant frequency, current mode, boost, flyback or SEPIC DC/DC controller that drives an N-channel power MOSFET in high input and output voltage converter applications. Soft-start can be programmed using an external capacitor.

The LTC3873 provides ±1.5% output voltage accuracy and consumes only 300μA quiescent current during normal operation and only 55μA during micropower start-up. Using a 9.3V internal shunt regulator, the LTC3873 can be powered from a high input voltage through a resistor or it can be powered directly from a low impedance DC voltage of 9V or less.

The LTC3873 is available in 8-lead ThinSOT and 2mm x 3mm DFN packages.

Features
  • VIN and VOUT Limited Only by External Components
  • Internal or Programmable External Soft-Start
  • Constant Frequency 200kHz Operation
  • Adjustable Current Limit
  • Current Sense Resistor Optional
  • Maximum 60V on SW Node with RDS(ON) Sensing
  • ±1.5% Voltage Reference Accuracy
  • Current Mode Operation for Excellent Line and Load Transient Response
  • Low Quiescent Current: 300µA
  • Low Profile (1mm) ThinSOT and (0.75mm) 2mm × 3mm DFN Package
Typical Application

Applications
  • Telecom Power Supplies
  • 42V and 12V Automotive Power Supplies
  • Portable Electronic Equipment
Packaging

Order Information
Part NumberPackageTempPrice(1-99)Price (1k)*
LTC3873EDDB#PBF3x2 DFN-8E$1.79
LTC3873EDDB#TRMPBF3x2 DFN-8E$1.79$1.30
LTC3873EDDB#TRPBF3x2 DFN-8E$1.79$1.25
LTC3873ETS8#PBFSOT-23E$1.79
LTC3873ETS8#TRMPBFSOT-23E$1.79$1.30
LTC3873ETS8#TRPBFSOT-23E$1.79$1.25
Demo Boards
Part NumberDescriptionPrice
DC1154ALTC3873ETS8 Isolated/Non-Isolated Demo Board | 36 ≤ Vin ≤ 72V, Vout: 3.3V/3A$75.00
Datasheet
Reliability Data
LT Journal
Press Release
LTspice
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