Analog Devices Inc. LT4363IS-2#TRPBF

Overview

LT4363IS-2#TRPBF 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 auto-retry fault recovery (LT4363-2 variant) with adjustable timer. It operates from 4V to 80V input, supports –60V reverse input protection, and is used in avionic power systems requiring robust hot-swap and intrinsic safety compliance.

For engineers reviewing the LT4363IS-2#TRPBF datasheet, LT4363IS-2#TRPBF pinout, LT4363IS-2#TRPBF application, or LT4363IS-2#TRPBF equivalent, key selection considerations include its 16-pin SO package, –40°C to +85°C industrial temperature grade, 1.275V FB reference, 125°C max junction temperature, and distinct LT4363-2 auto-restart behavior versus LT4363-1 latch-off operation.

Technical Context

The LT4363IS-2#TRPBF implements dual-loop protection: a voltage amplifier regulates GATE to hold FB at 1.275V during overvoltage, while a current amplifier maintains ΔVSNS = 50mV (or 25mV if OUT < 2V) during overcurrent. Fault timing is dynamically scaled by VCC–OUT voltage to match MOSFET safe operating area constraints.

Its LT4363-2 variant uses a 3-stage TMR pin state machine-warning (1.275V), shutdown (1.375V), and cool-down (4.3V → 0.5V)-to enable automatic restart after thermal recovery, with OV comparator inhibition preventing retry under sustained overvoltage. The 16-pin SO package includes dedicated UV, OV, SHDN, FLT, ENOUT, and TMR pins for full system-level control.

Key Specifications

Pinout & Package

LT4363IS-2#TRPBF is housed in a 16-lead plastic SO package (S package), with exposed thermal pad not present. Pin 1 is bottom-left corner (standard SO orientation). All pins are electrically defined per Analog Devices' LT4363 Rev. C datasheet.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC4365HDD-2#TRPBF and TPS26631PWPR, LT4363IS-2#TRPBF uniquely combines external MOSFET control, adjustable 27V+ clamp, SOA-adaptive timing, and –60V reverse tolerance - making it the only option for certified avionic and intrinsic safety designs requiring field-serviceable FETs and precise energy limiting.

Availability

LT4363IS-2#TRPBF is available at Aetrix Electronics and suitable for avionic power distribution, industrial hot-swap modules, intrinsic safety barriers, and battery-powered medical equipment requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LT4363IS-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. (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving aerospace, industrial, communications, and healthcare markets since 1965.

The LT4363IS-2#TRPBF belongs to ADI's Surge Stopper® family, engineered specifically for high-reliability power systems needing adaptive overvoltage/overcurrent protection with MOSFET gate control - targeting avionics, rail, and hazardous-area instrumentation.

FAQ

What is the key functional difference between LT4363IS-2#TRPBF and LT4363IS-1#TRPBF?

The LT4363IS-2#TRPBF implements auto-retry fault recovery: after overvoltage or overcurrent shutdown, it automatically restarts once the TMR pin discharges to 0.5V and the OV pin falls below 1.275V. In contrast, LT4363IS-1#TRPBF latches off permanently and requires active SHDN pin reset. This makes LT4363IS-2#TRPBF ideal for unattended systems like remote sensors, whereas LT4363IS-1#TRPBF suits safety-critical applications requiring manual intervention.

Can LT4363IS-2#TRPBF be used with P-channel MOSFETs?

No, LT4363IS-2#TRPBF is designed exclusively for N-channel MOSFETs. Its GATE driver is a charge-pump-based high-side driver referenced to the OUT pin, optimized to pull the gate 13V above the MOSFET source. Driving a P-channel device would require inverted logic, negative gate drive, and different timing - none of which are supported. Use LT4363IS-2#TRPBF only with external N-channel MOSFETs such as FDB33N25 or SiR626DP.

How does the TMR capacitor value affect fault timing in LT4363IS-2#TRPBF?

The TMR capacitor directly sets three timing intervals: early warning duration (16.67ms/µF), total regulation time before shutdown (96.9ms/µF for VDS=75V), and cool-down period (determined by 2µA pull-up/pull-down currents). For example, a 6.8µF capacitor yields ~113ms warning and ~659ms total regulation time at 75V VDS. Smaller capacitors reduce ride-through capability but improve response to fast transients - select based on expected surge profile per IEC 61000-4-5.

What is the maximum allowable voltage difference between SNS and OUT pins on LT4363IS-2#TRPBF?

The absolute maximum rating for SNS-to-OUT voltage is ±30V. Exceeding this risks permanent damage to the internal current-sense amplifier. During normal operation, ΔVSNS is regulated to 50mV (or 25mV under severe short), so the 30V limit primarily applies during fault conditions or layout-induced transients. Always place the sense resistor close to the MOSFET source and use Kelvin connections to minimize parasitic inductance and avoid overshoot.

Does LT4363IS-2#TRPBF support reverse polarity protection without additional components?

LT4363IS-2#TRPBF itself does not provide reverse polarity protection, but its SHDN, UV, OV, and VCC pins tolerate –60V, enabling implementation of back-to-back N-channel MOSFETs (instead of a Schottky diode) for efficient reverse-input protection. This configuration requires two matched N-MOSFETs and adds minimal voltage drop (<50mV at 5A) versus >0.3V for Schottky solutions - confirmed in the datasheet's "Reverse Input Protection" section.