LT3991IMSE-5#PBF

Overview

The LT3991IMSE-5#PBF is a high-efficiency step-down switching regulator from Analog Devices, operating with a fixed 5V output and delivering up to 1.2A of continuous current. It supports an input voltage range from 4V to 55V, utilizing a 2MHz fixed switching frequency for compact passive design. The device features ultra-low quiescent current of 2.8µA and operates in shutdown mode with 1.7µA supply current. It is housed in a 10-pin MSOP package and functions within a temperature range of -40°C to +125°C.

Feature Summary

• Integrated synchronous buck topology for high efficiency across wide load ranges
• Fixed 2MHz switching frequency enables use of small external inductors and capacitors
• Ultra-low quiescent current minimizes power consumption in battery-operated systems
• Thermal regulation and cycle-by-cycle current limit protect against overload conditions

Applications

• Portable instrumentation powered by single-cell lithium batteries
• Industrial control systems requiring isolated or non-isolated DC-DC conversion
• Automotive electronics operating within standard vehicle electrical architectures
• Communication infrastructure equipment needing stable low-noise power rails

Procurement Notes

Verify the specific suffix #PBF indicates lead-free RoHS compliance before ordering. Confirm the IMSE variant matches the required MSOP-10 package dimensions for PCB layout compatibility. Check official Analog Devices documentation for any recent pinout revisions or thermal pad requirements to ensure proper soldering and heat dissipation during assembly.

Selection Notes

Select this component when a fixed 5V output is required from inputs up to 55V. The 1.2A current rating suits moderate load applications without excessive heat sinking. Consider the 2MHz frequency for size constraints versus lower frequency alternatives. Ensure input voltage remains above 4V for proper regulation start-up and operation under all expected load conditions.

Part Context

This part belongs to the LT3991 family of high-voltage synchronous buck regulators. It shares architectural similarities with the LT3990 but offers higher current capability in a smaller package. The series is designed for applications demanding high efficiency and low standby power from high-voltage sources.

Replacement Considerations

LT3991EMSE-5#PBF serves as a verified alternative within the same product line, offering identical electrical specifications and functionality.