Analog Devices Inc. LTC4366IDDB-2#TRPBF

Overview

LTC4366IDDB-2#TRPBF from Analog Devices is a high-voltage surge stopper IC that protects downstream loads by regulating output voltage during overvoltage transients up to >500V 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.

For engineers reviewing the LTC4366IDDB-2#TRPBF datasheet, LTC4366IDDB-2#TRPBF pinout, LTC4366IDDB-2#TRPBF application, or LTC4366IDDB-2#TRPBF equivalent, this device serves as a rugged, floating overvoltage protector for 28V vehicle systems, industrial DC distribution, and avionic power rails requiring precise clamp voltage setting and MOSFET gate control under transient stress.

Technical Context

The LTC4366IDDB-2#TRPBF implements a floating topology where its OUT and BASE pins derive bias from the MOSFET source, enabling operation with input voltages far exceeding its own pin ratings. Its overvoltage regulation amplifier compares FB to OUT–1.23V and drives GATE to maintain clamping, while the TIMER pin controls surge duration via external capacitor timing (311 ms/µF).

Unlike latch-off variants, the "-2" suffix denotes auto-retry behavior: after a 9-second cool-down period following overvoltage fault shutdown, it autonomously restarts without external SD pin intervention. Shutdown reduces total quiescent current to <20 µA, with VDD and OUT supply regulators internally clamped at 12V and 5.7V respectively.

Key Specifications

Pinout & Package

Package: 8-lead (3 mm × 2 mm) plastic DFN with exposed pad (pin 9), rated θJA = 75°C/W when VSS is soldered to PCB.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC4366IDDB-2#TRPBF, the -1 variant provides deterministic fault hold but adds system-level reset complexity, while TPS26631RGER simplifies layout at the cost of voltage range and adjustability-making LTC4366IDDB-2#TRPBF uniquely suited for field-deployed, high-voltage, auto-recovering protection.

Availability

LTC4366IDDB-2#TRPBF is available at Aetrix Electronics and suitable for 28V vehicle systems, industrial high-voltage DC distribution, and avionic power rail protection requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for LTC4366IDDB-2#TRPBF 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 leader specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision, power, and reliability-critical applications.

The LTC4366 product line delivers rugged, floating overvoltage protection ICs designed specifically for harsh-environment power systems-including aerospace, transportation, and industrial infrastructure-where sustained operation during multi-hundred-volt transients is mandatory.

FAQ

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

The LTC4366IDDB-2#TRPBF implements auto-retry behavior: after an overvoltage fault, it enters a 9-second cool-down period and then automatically resumes operation. In contrast, the LTC4366IDDB-1#TRPBF latches off permanently until the SD pin is actively toggled low-then-high to clear the fault. This makes the -2 version ideal for unattended or remote systems where manual intervention is impractical, while the -1 suits safety-critical designs requiring explicit operator acknowledgment.

How does LTC4366IDDB-2#TRPBF achieve >500V input tolerance despite its 12V-rated pins?

LTC4366IDDB-2#TRPBF achieves >500V input tolerance through a floating architecture: its critical circuitry-including the charge pump and overvoltage amplifier-is powered from the OUT pin, which connects to the source of the external N-MOSFET. Since the MOSFET isolates the IC from the full input voltage, only the gate drive (GATE–OUT ≤12V) and bias resistors (RSS, RIN) experience high potential. The IC itself sees only local voltage differences-enabling protection far beyond its absolute maximum pin ratings.

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

The BASE pin on LTC4366IDDB-2#TRPBF drives the base of an external PNP transistor configured as a shunt regulator, allowing reduction of current through the main RSS resistor. It is used when high input voltages demand large RSS values that would otherwise require oversized, high-wattage resistors. By diverting base current through RSS, the PNP solution enables up to 35× higher RSS resistance-cutting power dissipation and PCB footprint-while maintaining regulation integrity in >400V applications.

Can LTC4366IDDB-2#TRPBF protect against both overvoltage and undervoltage conditions?

LTC4366IDDB-2#TRPBF provides overvoltage protection only. It includes two undervoltage lockout (UVLO) thresholds on the OUT pin-2.6V (UVLO1) and 4.75V (UVLO2)-but these serve solely to enable internal circuitry (regulation amplifier at UVLO1, charge pump at UVLO2) during startup and normal operation. They do not trigger protective action or shut down the MOSFET during low-input conditions. For coordinated overvoltage *and* undervoltage protection, LTC4366IDDB-2#TRPBF must be paired with a separate UVLO monitor or supervisor IC.

What is the minimum recommended bypass capacitance on the OUT pin of LTC4366IDDB-2#TRPBF, and why is it critical?

The minimum recommended bypass capacitance on the OUT pin of LTC4366IDDB-2#TRPBF is 0.22 µF, connected directly to VSS. This capacitor stabilizes the 5.7V internal shunt-regulated supply for the charge pump and overvoltage amplifier. Insufficient capacitance causes voltage droop during gate charging or regulation events, leading to erratic GATE drive, premature fault triggering, or failure to reach full 12V gate enhancement-especially under high load current. Ceramic X7R types are preferred for low ESR and stable performance across temperature.