LTC3873

PRODUCTION

No R_SENSE^™ Constant Frequency Current Mode Boost/Flyback/SEPIC DC/DC Controller

Data Sheet (Rev. C) Product Selection Table

Part Models: 4
1ku List Price: Starting From $1.53

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Part Details

V_IN and V_OUT 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 R_DS(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

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.


	LTC3873	LTC3873-5
V_CC UV⁺	8.4V	4.1V
V_CC UV^–	4V	2.9V

APPLICATIONS

Telecom Power Supplies
42V and 12V Automotive Power Supplies
Portable Electronic Equipment

Part Models: 4
1ku List Price: Starting From $1.53

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
LTC3873EDDB#TRMPBF	8-Lead DFN (3mm x 2mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LTC3873EDDB#TRPBF	8-Lead DFN (3mm x 2mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LTC3873ETS8#TRMPBF	8-Lead SOT-23	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LTC3873ETS8#TRPBF	8-Lead SOT-23	Material Declaration Reliablity Data	Ultra Librarian SamacSys

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

Hardware Ecosystem

Parts	Product Life Cycle	Description
Isolated µModule Converters 2
LTM8047	RECOMMENDED FOR NEW DESIGNS	3.1V_IN to 32V_IN Isolated μModule (Power Module) DC/DC Converter
LTM8048	RECOMMENDED FOR NEW DESIGNS	3.1V_IN to 32V_IN Isolated μModule (Power Module) DC/DC Converter with LDO Post Regulator

Parts	Product Life Cycle	Description
LTC3873-5	PRODUCTION	No R_SENSE^™ Constant Frequency Current Mode Boost/Flyback/SEPIC DC/DC Controller

Tools & Simulations

LTspice 2

Models for the following parts are available in LTspice:

LTC3873
LTC3873-5

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

LTC3873ETS8 Isolated/Non-Isolated Demo Board | 36 ≤ VIN ≤ 72V, VOUT: 3.3V/3A

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Product Details

Demonstration circuit DC1154 is a Telecom non isolated DC/DC converter featuring the LTC3873 constant frequency current mode flyback controller. The DC1154 converts 36V to 72V input voltage to an isolated 3A of output current at 3.3V. The 200kHz constant frequency operation is maintained down to very light load to reduce low frequency noise generated over a wide range of load current. The DC1154 also provides an isolated design by installing the optocoupler and LTC4430 related circuitry. The demonstration circuit can be easily modified to generate different output voltages up to 15V. As output voltage is increased, the maximum output current must be reduced to limit the output power to no more than 10W.

Resources

DC1154A - Schematic
29.00K

DC1154A - Demo Manual
313.00K

DC1154A - Design File
711.00K

Latest Discussions

2 Years Ago

Part Details

Documentation

Data Sheet 1

Reliability Data 1

User Guide 1

Technical Articles 1