Analog Devices Inc. LT4363IMS-1#PBF

Overview

LT4363IMS-1#PBF from Analog Devices is a high-voltage surge stopper IC that controls an external N-channel MOSFET to regulate output voltage during overvoltage transients up to 150V, limits current via 50mV SNS–OUT sense threshold, and features latch-off fault behavior (LT4363-1 variant) for industrial power systems requiring robust fault containment. It operates from 4V to 80V input, supports –60V reverse input protection, and delivers <5µs overcurrent response.

For engineers reviewing the LT4363IMS-1#PBF datasheet, LT4363IMS-1#PBF pinout, LT4363IMS-1#PBF application, or LT4363IMS-1#PBF equivalent, this page provides verified package mapping (12-lead MSOP), confirmed thermal specs (–40°C to 85°C), validated UV/OV comparator thresholds (1.275V ±12mV), real-world timer behavior (TMR thresholds at 1.275V/1.375V/0.5V), and precise gate drive characteristics (ΔVGATE = 13V typ above OUT).

Technical Context

The LT4363IMS-1#PBF implements dual independent protection loops: a voltage servo loop using FB feedback to clamp output at 1.275V × (1 + R1/R2), and a current servo loop regulating ΔVSNS to 50mV (or 25mV when OUT < 2V). Fault timing is dynamically scaled by VCC–OUT voltage to match MOSFET safe operating area constraints.

Its LT4363-1 variant latches GATE low after TMR reaches 1.375V and requires active SHDN reset (≥100µs low pulse); it lacks OV pin functionality (pin 12 is NC), unlike LT4363-2. The MSOP package provides θJA = 135°C/W and supports exposed-pad grounding only in DFN variants - not applicable here.

Key Specifications

Pinout & Package

LT4363IMS-1#PBF uses a 12-lead plastic MSOP package (4.0mm × 3.0mm × 1.1mm), rated for –40°C to +85°C operation, with θJA = 135°C/W. Pin 1 is FB; pin 12 is NC (no connection) - confirmed for LT4363-1 variant per datasheet pin configuration diagrams.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LT4363IMS-2#PBF, LT4363IMS-1#PBF provides deterministic fault containment without recovery attempts, while versus TPS26631PWPR it offers full design flexibility in MOSFET selection, timing adjustment, and output voltage setting - essential for high-reliability industrial and avionic systems.

Availability

LT4363IMS-1#PBF is available at Aetrix Electronics and suitable for avionic power distribution, industrial hot-swap modules, and intrinsic safety barriers requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for LT4363IMS-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 leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and aerospace markets since 1965.

The LT4363 product line was designed specifically for high-voltage surge protection in harsh environments, emphasizing latch-off reliability, reverse-input survivability, and MOSFET SOA-aware fault timing - targeting mission-critical power infrastructure.

FAQ

What is the function of the NC pin on LT4363IMS-1#PBF?

The NC (No Connect) pin on LT4363IMS-1#PBF is pin 12, explicitly designated as unconnected in the datasheet for the LT4363-1 variant. It must remain electrically floating - no routing, pull-up, or tie to GND/VCC. This distinguishes LT4363IMS-1#PBF from LT4363IMS-2#PBF, where pin 12 functions as the OV input. Confirming NC status avoids misinterpretation of pin 12 as functional in LT4363IMS-1#PBF layouts.

How does LT4363IMS-1#PBF differ from LT4363IMS-2#PBF in fault handling?

LT4363IMS-1#PBF implements latch-off behavior: once the TMR pin reaches 1.375V, GATE and FLT remain low until SHDN is actively pulsed low for ≥100µs. In contrast, LT4363IMS-2#PBF automatically restarts after TMR discharges to 0.5V during cool-down. This makes LT4363IMS-1#PBF suitable for safety-critical applications requiring guaranteed fault isolation, while LT4363IMS-2#PBF suits systems needing autonomous recovery.

Can LT4363IMS-1#PBF be used with P-channel MOSFETs?

No - LT4363IMS-1#PBF is designed exclusively for N-channel MOSFETs configured as high-side switches. Its GATE driver sources current relative to the OUT pin (not GND), enabling proper enhancement of N-MOSFETs with source tied to load. Driving a P-MOSFET would require inverted logic, incompatible gate-reference architecture, and lacks internal level-shifting support. Use dedicated P-MOSFET controllers like LTC4412 for such topologies.

What is the minimum TMR capacitor value required for stable operation of LT4363IMS-1#PBF?

The minimum TMR capacitor value for LT4363IMS-1#PBF is 10nF, as specified in the datasheet to ensure loop stability and reliable fault timing. Using less than 10nF risks oscillation in the regulation loop and inconsistent early-warning (1.275V) and shutdown (1.375V) timing. For typical 100ms surge ride-through, a 6.8µF capacitor is commonly applied - yielding ~97ms regulation time at VDS = 75V per the tREG formula.

Does LT4363IMS-1#PBF support reverse polarity protection without additional components?

Yes - LT4363IMS-1#PBF inherently supports reverse input protection down to –60V on the VCC pin without external diodes or MOSFETs, due to its absolute maximum rating and internal ESD structure. For full reverse-polarity blocking, however, a back-to-back N-MOSFET configuration (using LT4363IMS-1#PBF's GATE to drive both devices) is required - eliminating the 0.4V–0.7V forward drop of Schottky diodes and improving efficiency in bidirectional power paths.