Analog Devices Inc. LT4363HDE-1#TRPBF

Overview

LT4363HDE-1#TRPBF 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 100V, limits current via 50mV SNS–OUT sense threshold, and latches off after fault timeout. It operates from 4V to 80V input, supports –40°C to 125°C ambient, and delivers precise overvoltage clamping (e.g., 27V) in avionics and industrial power systems.

For engineers reviewing the LT4363HDE-1#TRPBF datasheet, LT4363HDE-1#TRPBF pinout, LT4363HDE-1#TRPBF application, or LT4363HDE-1#TRPBF equivalent, this page provides verified functional specifications, DFN-12 package layout, thermal-rated operation details, fault timing behavior, and real-world substitution guidance for high-reliability surge protection designs.

Technical Context

The LT4363HDE-1#TRPBF implements dual-fault protection with independent overvoltage (regulated clamp at FB = 1.275V) and overcurrent (50mV SNS–OUT limit) detection. Its adaptive fault timer charges TMR based on V_CC–V_OUT, scaling current from ~4µA (low V_DS) to 50µA (75V V_DS) during overvoltage, enabling SOA-aware shutdown.

It features latch-off behavior (LT4363-1 variant): FLT pulls low at TMR = 1.275V, GATE turns off at TMR = 1.375V, and remains latched until SHDN is pulsed low ≥100µs. UV/SHDN inputs support undervoltage blocking and <7µA shutdown quiescent current, while GATE drive delivers 13V above OUT with 14V clamp.

Key Specifications

Pinout & Package

LT4363HDE-1#TRPBF uses a 12-lead (4mm × 3mm) plastic DFN package with exposed pad (Pin 13) connected to GND. Thermal resistance θ_JA = 43°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LT4363HDE-2#TRPBF, the LT4363HDE-1#TRPBF provides deterministic fail-safe shutdown essential for avionics and safety-critical PLCs, while TPS26631RHFR trades configurability for integration - making LT4363HDE-1#TRPBF optimal when adjustable clamping, precise current limiting, and guaranteed latch-off are mandatory.

Availability

LT4363HDE-1#TRPBF is available at Aetrix Electronics and suitable for avionic power distribution, industrial PLC backplane protection, and intrinsic safety barrier designs requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for LT4363HDE-1#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 instrumentation, industrial automation, and aerospace systems.

The LT4363 product line delivers robust, high-voltage surge protection for mission-critical power systems - designed specifically for applications demanding latch-off reliability, wide temperature operation, and adaptive MOSFET stress management.

FAQ

What is the key functional difference between LT4363HDE-1#TRPBF and LT4363HDE-2#TRPBF?

The LT4363HDE-1#TRPBF implements latch-off behavior: after fault timeout, GATE and FLT remain low until SHDN is actively pulsed. In contrast, LT4363HDE-2#TRPBF automatically restarts once the TMR capacitor discharges to 0.5V. This makes LT4363HDE-1#TRPBF mandatory for fail-safe systems where unattended recovery is prohibited - such as flight control units or safety PLCs. Both share identical pinout, specs, and package.

How does the LT4363HDE-1#TRPBF achieve adaptive fault timing based on MOSFET stress?

The LT4363HDE-1#TRPBF measures V_CC–V_OUT to infer V_DS across the external MOSFET and scales the TMR charging current accordingly - from ~4µA at low V_DS to 50µA at 75V V_DS. This ensures shorter fault timeouts under high-stress conditions, keeping the MOSFET within its Safe Operating Area. The relationship is documented in Figure 1 of the LT4363 datasheet and validated across –40°C to +125°C.

Can the LT4363HDE-1#TRPBF be used with back-to-back N-MOSFETs for reverse polarity protection?

Yes - the LT4363HDE-1#TRPBF supports reverse input protection to –60V on VCC, SHDN, UV, and OV pins. When paired with back-to-back N-MOSFETs (source-to-source), it eliminates the 0.3V–0.5V forward drop of Schottky diodes, improving efficiency and available output voltage. The SHDN pin's –60V tolerance and UV comparator enable robust control of the series FETs during reverse-battery events.

What is the minimum TMR capacitor value required for stable operation of LT4363HDE-1#TRPBF?

A minimum 10nF capacitor is required on the TMR pin to compensate the control loop and ensure stability during regulation. Smaller values risk oscillation or erratic fault timing. For typical 100ms surge ride-through, a 1µF capacitor is commonly used - yielding ~97ms regulation time plus 16.7ms warning period per the datasheet's t_REG and t_WARNING equations. All values are validated over the full –40°C to +125°C range.

Does the LT4363HDE-1#TRPBF support adjustable overvoltage and undervoltage thresholds?

Yes - the UV and OV pins accept externally set thresholds via resistor dividers from VCC. UV threshold is 1.275V ±12mV; OV threshold (on LT4363-2 variants only) is also 1.275V ±7.5mV. For LT4363HDE-1#TRPBF (a -1 variant), the OV pin is not present - only UV is active. Therefore, adjustable undervoltage lockout is supported, but overvoltage threshold adjustment requires using the FB pin and resistive divider to set the regulated clamp voltage.