LTC3859AIUHF#PBF

DC DC Switching Controllers Overview

The LTC3859AIUHF#PBF is a high-performance triple output synchronous DC/DC switching regulator controller manufactured by Analog Devices. It drives all N-channel power MOSFET stages for buck, buck/boost, and SEPIC topologies. The device operates from a wide input supply range of 4.5V to 38V, with an operating supply voltage of the same range. Output voltages are adjustable from 800mV to 24V for buck configurations and up to 60V for boost applications. The switching frequency is programmable between 75kHz and 850kHz. It features a constant frequency current mode architecture with phase-lock capability. The component is housed in a 38-lead QFN package (5x7mm) with an exposed pad, rated for industrial temperatures from -40°C to +125°C.

DC DC Switching Controllers Feature Summary

• Supports multiple output topologies including buck, buck/boost, and SEPIC configurations within a single controller.
• Features a constant frequency current mode architecture allowing for phase-lockable switching frequencies up to 850kHz.
• Includes independent TRACK/SS pins for each controller to manage start-up sequencing and tracking.
• Operates from a wide input voltage range of 4.5V to 38V, enabling bias from auxiliary supplies as low as 2.5V after startup.

DC DC Switching Controllers Applications

• Triple output power systems requiring buck and boost conversion
• SEPIC converter designs for non-inverting step-up/down regulation
• Distributed DC power systems with wide input voltage ranges
• Automotive always-on systems requiring robust voltage regulation

DC DC Switching Controllers Procurement Notes

Verify the specific suffix against the manufacturer's official datasheet to confirm temperature grade and packaging type. The #PBF suffix indicates lead-free RoHS compliance. Confirm availability status directly with authorized distributors as stock levels fluctuate. Ensure the ordering information matches the required package style and thermal performance specifications for your application.

DC DC Switching Controllers Selection Notes

Select this controller when designing multi-rail power architectures that require synchronized or tracked outputs. It is suitable for applications needing flexible topology combinations such as buck and boost simultaneously. Consider the 38-QFN package for thermal management requirements. Verify that the external MOSFET selection supports the maximum current and voltage ratings defined by the controller's drive capabilities.

DC DC Switching Controllers Part Context

The LTC3859A belongs to the LTC3859 family of triple output synchronous controllers. This series is designed for high-efficiency power management in complex electronic systems. The AIUHF variant specifically denotes the industrial temperature grade and the QFN package configuration. It serves as a core component for generating multiple regulated rails from a single input source.

DC DC Switching Controllers FAQ

Can the LTC3859AIUHF#PBF operate with an input voltage lower than 4.5V?

Yes, if the device is biased from the output of a boost converter or another auxiliary supply, it can operate from an input supply as low as 2.5V after startup.

What is the maximum switching frequency supported by this controller?

The LTC3859 supports a phase-lockable switching frequency of up to 850kHz.

Does the controller support output voltage tracking?

Yes, it features independent TRACK/SS pins for each controller to ramp output voltages during start-up and enable tracking functions.