Features and Benefits
- Wide Input Range: 2.5V to 60V
- Integrated Buck-Boost Supply for 7.5V MOSFET Gate Drive
- Programmable Constant-Current Operation with Current Monitor Output
- Low IQ: 75μA, 12VIN to 3.3VOUT
- Selectable Low Output Ripple Burst Mode® Operation
- VOUT Up to 60V
- Adjustable and Synchronizable: 50kHz to 1MHz
- Internal OVLO Protects for Input Transients Up to 80V
- Accurate Input Overvoltage and Undervoltage Threshold
- Programmable Soft-Start with Voltage Tracking
- Power Good and Output OVP
- 28-Lead TSSOP and 38-Lead 4mm × 6mm QFN Packages
The LT3840 is a high voltage synchronous step-down switching regulator controller capable of operating from a 2.5V to 60V supply.
The LT3840’s low quiescent current, when configured for user selectable Burst Mode operation, helps extend run time in battery-powered systems by increasing efficiency at light loads. The LT3840 uses a constant frequency, current mode architecture. High current applications are possible with large N-channel gate drivers capable of driving multiple low RDS(ON) MOSFETs.
An integrated buck-boost switching regulator generates a 7.5V bias supply voltage for MOSFET gate drive and IC power allowing higher efficiency operation over the entire input voltage range and eliminating the need for an external bias voltage. An accurate current limit set point regulates the maximum output current. A current monitor reports the average output current.
- Automotive Supplies
- Industrial Systems
- Distributed DC 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 1909A is a 150kHz, 60V current mode DC/DC step-down converter with accurate current limit featuring the LT3840. The circuit operates from a VIN range of 4.5V to 60V, survives an 80V transient, and outputs 3.3V at 20A (66W). An integrated buck-boost switching regulator generates a 7.5V bias supply voltage for MOSFET gate drive and IC power to increase the overall efficiency by reducing the power loss. A soft-start feature controls the output voltage slew rate at start-up, reducing current surges and voltage overshoots. The modes of operation (Burst Mode®, discontinuous current mode and continuous current mode) are jumper selectable.
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:
LT3840 Companion Parts
Recommended Related Parts
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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.