Features and Benefits
- Wide Operating VIN Range: 4.5V to 150V
- Wide VOUT Range: 0.8V to 60V
- 9μA IQ when Regulating 48VIN to 3.3VOUT
- 16μA IQ when Regulating 12VIN to 3.3VOUT
- Very Low Dropout Operation: 100% Duty Cycle
- Adjustable Input Overvoltage Lockout
- Programmable PGOOD Undervoltage Monitor
- RSENSE or Inductor DCR Current Sensing
- Selectable High Efficiency Burst Mode® Operation or Pulse-Skipping Mode at Light Loads
- Programmable Fixed Frequency: 50kHz to 850kHz
- Phase-Lockable Frequency: 75kHz to 800kHz
- Internal Fixed Soft-Start and External Programmable Soft-Start or Voltage Tracking
- Strong MOSFET Gate Driver with Selectable Undervoltage Lockout Thresholds
- Optional External NMOS for Gate Driver Bias in High Power Applications
The LTC3894 is a high voltage step-down DC/DC switching regulator controller. It drives a P-channel power MOSFET switch allowing 100% duty cycle operation. It enables a low part count, simple, and robust solution for high reliability, high voltage applications.
The LTC3894 operates over a wide input voltage range from 4.5V to 150V and can regulate output voltages from 0.8V to 60V. It offers excellent light load efficiency, drawing only 9μA quiescent current while regulating the output voltage with no load. Its peak current mode, constant frequency architecture provides for good control of switching frequency and output current limit. The switching frequency can be programmed from 50kHz to 850kHz with an external resistor and can be synchronized to an external clock from 75kHz to 800kHz.
The LTC3894 offers programmable output voltage soft-start or tracking. Safety features include overvoltage, overcurrent and overtemperature protection with a power good output monitor with adjustable threshold.
The LTC3894 is available in a thermally enhanced 20-Pin TSSOP package with leads removed to accommodate high voltage creepage and clearance requirements.
- Automotive and Industrial Power Systems
- Telecommunication Power Systems
- Distributed Power Systems
Product Lifecycle Recommended for New Designs
This product has been released to the market. The data sheet contains all final specifications and operating conditions. For new designs, ADI recommends utilization of these products.
Evaluation Kits (1)
Demonstration circuit 2506A is a high voltage, currentmode DC/DC step-down converter featuring the LTC3894.
The board operates from an input range of 6V to 150V, and provides a 5V, 3A output. The PMOSFET architecture allows it to operate seamlessly up to 100% duty cycle, and function as a saturated switch below the regulation threshold. This application has undervoltage lockout programmed for a 6V minimum input to assure adequate gate drive for the MOSFET. It operates at 150kHz and may be synchronized to an external clock. A soft-start feature controls output voltage slew rate at start-up, reducing current surge and voltage overshoot. Burst Mode operation that improves efficiency at light loads can be enabled with a jumper. A power good output signal is provided.
This board is suitable for a wide range of automotive, telecom, industrial, and other applications. The LTC3894 is available in a thermally enhanced 20-pin TSSOP package with skipped leads to accommodate high voltage creepage and clearance requirements. For other output requirements, see the LTC3894 data sheet or contact the LTC factory.
Documentation & Resources
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.
Models for the following parts are available in LTspice:
LTpowerCAD® is a power supply design program which selects power stage components, provides detailed power efficiency, shows quick loop Bode plot stability and load transient analysis, and can export to LTspice for simulation.
To open the project file for this circuit:
Step 1: Download and install LTpowerCAD on your computer.
Step 2: Click on the link(s) in the section below to download part-specific project files.
Step 3: If the project file doesn't run, right-click the link and select "Save Target As." Then start the LTpowerCAD tool and open the project file by selecing "Open Project" from the "File" menu.
LTpowerCAD Project Files
Design tools for the following parts are available in LTpowerCAD:
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
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Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.