Analog Devices Inc. LT4363HMS-1#PBF

Overview

LT4363HMS-1#PBF from Analog Devices is a high-voltage surge stopper IC that controls an external N-channel MOSFET to regulate output voltage during transients up to 150V, provides adjustable 27V overvoltage clamping, delivers ≤5 µs overcurrent response, and operates across –40°C to 125°C in a 12-lead MSOP package. It protects avionics and industrial power rails from surges while maintaining load operation.

For engineers reviewing the LT4363HMS-1#PBF datasheet, LT4363HMS-1#PBF pinout, LT4363HMS-1#PBF application, or LT4363HMS-1#PBF equivalent, key selection criteria include its 4V–80V input range, 50 mV current-sense threshold, latch-off fault behavior (LT4363-1), UV/OV comparator thresholds at 1.275 V, and 7 µA shutdown current - all critical for hot-swap and intrinsic safety designs.

Technical Context

The LT4363HMS-1#PBF implements dual-fault protection using independent voltage and current regulation loops: an internal amplifier maintains 1.275 V at FB during overvoltage, while a precision current-sense amplifier limits ΔVSNS to 50 mV (25 mV if OUT < 2 V). Its TMR pin uses adaptive charging current proportional to VCC–OUT to dynamically scale fault timing per MOSFET SOA constraints.

It features latch-off behavior (LT4363-1 variant): after fault timeout, GATE and FLT remain low until manual reset via SHDN pulse ≥100 µs. The device supports reverse input protection down to –60 V, includes back-to-back MOSFET control logic, and tolerates SHDN voltages from –60 V to 100 V without damage.

Key Specifications

Pinout & Package

LT4363HMS-1#PBF is housed in a 12-lead plastic MSOP package with exposed thermal pad (not electrically connected). Pin 1 is marked by dot; top view orientation matches standard MSOP conventions.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LT4363IMS-1#PBF and LT4363HDE-1#PBF, the LT4363HMS-1#PBF uniquely balances extended temperature capability with MSOP's ease of assembly and moderate thermal performance - ideal for space-constrained avionics modules requiring H-grade reliability without DFN rework complexity.

Availability

LT4363HMS-1#PBF is available at Aetrix Electronics and suitable for avionic power distribution, industrial hot-swap modules, intrinsic safety barriers, and battery-powered monitoring nodes requiring stable component supply across extended temperature ranges.

Supply support for LT4363HMS-1#PBF 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 instrumentation, industrial automation, and aerospace systems.

The LT4363 product line delivers high-voltage surge protection with adaptive fault timing and latch-off behavior, designed specifically for mission-critical power rails in avionics, transportation, and hazardous-location equipment.

FAQ

What is the key functional difference between LT4363HMS-1#PBF and LT4363HMS-2#PBF?

The LT4363HMS-1#PBF implements latch-off fault behavior: after overvoltage or overcurrent timeout, GATE and FLT remain low until manually reset via SHDN. In contrast, LT4363HMS-2#PBF automatically restarts after cool-down. This makes LT4363HMS-1#PBF preferred for safety-critical systems where uncontrolled retry could exacerbate faults. Both share identical pinout, specs, and H-grade temperature rating.

Can LT4363HMS-1#PBF drive a logic-level N-channel MOSFET directly?

Yes. The LT4363HMS-1#PBF's GATE pin uses an internal charge pump to deliver up to 13 V above the OUT pin, sufficient to fully enhance logic-level N-MOSFETs with VGS(th) ≤ 2.5 V. Its 14 V internal clamp protects against overdrive, and the pull-down current exceeds 50 mA - ensuring fast turn-off even with large gate capacitance.

How does the TMR capacitor value affect fault timing in LT4363HMS-1#PBF?

The TMR capacitor sets three timing intervals: early warning (FLT low), fault shutdown (GATE off), and cool-down (for LT4363-2 only). For LT4363HMS-1#PBF, a 6.8 µF capacitor yields ~97 ms total regulation time at VDS = 75 V. Timing scales linearly with capacitance but inversely with adaptive TMR current - which itself depends on VCC–OUT. Refer to Figure 1 in the datasheet for exact curves.

Is LT4363HMS-1#PBF compatible with reverse battery protection using back-to-back MOSFETs?

Yes. LT4363HMS-1#PBF supports reverse input protection: its SHDN, UV, OV, and VCC pins tolerate –60 V, and it can drive two N-MOSFETs in series with body diodes opposing each other. This replaces lossy Schottky diodes, reducing voltage drop and power dissipation - especially valuable in 12 V and 24 V battery systems where efficiency and thermal management are critical.

What is the minimum recommended TMR capacitor value for stable operation of LT4363HMS-1#PBF?

The datasheet specifies a minimum TMR capacitor of 10 nF to ensure loop stability and proper fault timing. Using smaller values risks erratic FLT assertion, insufficient warning time, or oscillation during regulation. For most applications, 100 nF to 10 µF is typical; 6.8 µF is commonly used to achieve ~100 ms fault window at high VDS. Always verify stability with actual MOSFET and load conditions.