Analog Devices Inc. LTC4366IDDB-2#TRMPBF

Overview

LTC4366IDDB-2#TRMPBF from Analog Devices is a high-voltage surge stopper IC that protects downstream loads by regulating output voltage during overvoltage transients using an external N-channel MOSFET. It features auto-retry fault recovery, adjustable 1.23V FB reference, 9-second internal cool-down timer, and operates across –40°C to +85°C in an 8-lead 3mm × 2mm DFN package. It is used in 28V vehicle systems requiring uninterrupted operation during 250V input surges.

For engineers reviewing the LTC4366IDDB-2#TRMPBF datasheet, LTC4366IDDB-2#TRMPBF pinout, LTC4366IDDB-2#TRMPBF application, or LTC4366IDDB-2#TRMPBF equivalent, key selection criteria include its floating topology support, adjustable overvoltage clamp via FB divider, GATE drive capability up to 12V above OUT, shutdown quiescent current <14µA, and auto-retry behavior distinguishing it from latch-off LTC4366-1 variants.

Technical Context

The LTC4366IDDB-2#TRMPBF implements a floating architecture where regulation circuitry is powered from the MOSFET source (OUT pin), enabling operation with input voltages exceeding 500V. Its overvoltage regulation amplifier compares FB to a 1.23V reference below OUT and drives GATE to maintain clamping.

It integrates dual shunt regulators (11.7V on VDD, 5.5V on OUT), a 9µA TIMER pin current source, and a 200mA fast pull-down on GATE during overvoltage events. The -2 version auto-restarts after a fixed 9-second cool-down period following overvoltage fault latching.

Key Specifications

Pinout & Package

Package: 8-lead (3mm × 2mm) plastic DFN with optional exposed pad connected to VSS.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar overvoltage protection applications.

Compared with LTC4366IDDB-1#TRMPBF, the LTC4366IDDB-2#TRMPBF provides autonomous recovery ideal for remote or inaccessible systems, while TPS26631RTJT offers integrated current limiting but lacks the high-voltage floating capability and precision adjustable clamp essential for 28V+ vehicle and avionic applications.

Availability

LTC4366IDDB-2#TRMPBF is available at Aetrix Electronics and suitable for 28V vehicle systems, avionic power distribution, and industrial high-voltage DC networks requiring stable component supply with guaranteed long-term availability.

Supply support for LTC4366IDDB-2#TRMPBF includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Analog Devices, Inc. is a global semiconductor company specializing in high-performance analog, mixed-signal, and digital signal processing technologies.

The LTC4366 product line delivers high-voltage surge protection ICs designed specifically for rugged floating-topology applications in automotive, avionic, and industrial power systems where input transients exceed 250V.

FAQ

What is the key functional difference between LTC4366IDDB-2#TRMPBF and LTC4366IDDB-1#TRMPBF?

The LTC4366IDDB-2#TRMPBF implements auto-retry fault recovery: after an overvoltage event triggers the 9-second cool-down timer, it automatically clears the fault and resumes normal operation. In contrast, the LTC4366IDDB-1#TRMPBF latches off permanently and requires an external toggle of the SD pin to reset. This makes the LTC4366IDDB-2#TRMPBF ideal for unattended or remote systems where manual intervention is impractical.

How does the LTC4366IDDB-2#TRMPBF achieve operation with input voltages exceeding 500V?

The LTC4366IDDB-2#TRMPBF achieves ultra-high input voltage tolerance through its floating architecture: regulation circuitry-including the overvoltage amplifier, charge pump, and FB reference-is powered from the OUT pin (MOSFET source), not the input supply. This isolates internal circuitry from input transients, making the maximum survivable voltage dependent solely on the external N-channel MOSFET's breakdown rating-not the LTC4366IDDB-2#TRMPBF's own pin ratings.

What is the role of the BASE pin on the LTC4366IDDB-2#TRMPBF, and when should it be used?

The BASE pin on the LTC4366IDDB-2#TRMPBF drives the anode of an external PNP transistor configured as a shunt regulator, enabling reduction of power dissipation in the RSS resistor. It is used when physical size or thermal constraints prevent using a high-wattage RSS resistor in high-input-voltage applications. Connecting an external PNP allows RSS values up to 35× larger than in standard configurations, significantly shrinking board footprint and improving reliability in space-constrained designs.

Can the overvoltage clamp voltage of the LTC4366IDDB-2#TRMPBF be adjusted, and how is it set?

Yes, the overvoltage clamp voltage of the LTC4366IDDB-2#TRMPBF is fully adjustable via an external resistive divider from OUT to ground connected to the FB pin. The internal regulation amplifier maintains 1.23V across R_FB1, so the clamp voltage equals V_OUT = 1.23V × (1 + R_FB2/R_FB1). For example, using R_FB1 = 12.4kΩ and R_FB2 = 422kΩ sets a 43V clamp-commonly used in 28V vehicle systems to handle ISO 7637-2 Pulse 5a transients.

What thermal considerations apply to the LTC4366IDDB-2#TRMPBF's DFN package in high-power surge scenarios?

The LTC4366IDDB-2#TRMPBF's 3mm × 2mm DFN package has θ_JA = 75°C/W when the exposed pad is soldered to a PCB ground plane, rising to 135°C/W if unsoldered. During sustained overvoltage regulation, power dissipation occurs primarily in the external MOSFET-not the LTC4366IDDB-2#TRMPBF-so the IC itself remains cool. However, proper thermal relief for the VSS pad and adequate copper area are essential to sustain 9-second cool-down cycles repeatedly without junction temperature exceeding 125°C.