No RSENSE™ Constant Frequency Current Mode Boost/Flyback/SEPIC DC/DC Controller
Features and Benefits
- 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
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.
- Telecom Power Supplies
- 42V and 12V Automotive Power Supplies
- Portable Electronic Equipment
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (1)
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.
Tools & Simulations
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.
To launch ready-to-run LTspice demonstration circuits for this part:
Step 1: Download and install LTspice on your computer.
Step 2: Click on the link in the section below to download a demonstration circuit.
Step 3: If LTspice does not automatically open after clicking the link below, you can instead run the simulation by right clicking on the link and selecting “Save Target As.” After saving the file to your computer, start LTspice and open the demonstration circuit by selecting ‘Open’ from the ‘File’ menu.
Models for the following parts are available in LTspice:
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.
Sample & Buy
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 Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.