Analog Devices Inc. LT4363HDE-1#PBF

Overview

LT4363HDE-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, features adjustable UV/OV comparators (1.275V thresholds), and operates across –40°C to 125°C in a 12-lead 4mm × 3mm DFN package. It protects avionic and industrial power rails.

For engineers reviewing the LT4363HDE-1#PBF datasheet, LT4363HDE-1#PBF pinout, LT4363HDE-1#PBF application, or LT4363HDE-1#PBF equivalent, key selection considerations include its latch-off fault behavior (LT4363-1 variant), 4V–80V input range, 7µA shutdown current, reverse input protection to –60V, and thermal grade suitability for under-hood or aerospace environments.

Technical Context

The LT4363HDE-1#PBF implements dual-fault protection: overvoltage regulation via FB-servo loop holding 1.275V at feedback pin, and overcurrent limiting by controlling GATE to clamp ΔVSNS to 50mV (25mV if OUT < 2V). Fault timing is dynamically scaled by VCC–OUT voltage to optimize MOSFET safe operating area usage.

It integrates precision UV/OV comparators with 12mV/7.5mV hysteresis, a 14V GATE clamp, and a TMR pin with three-phase operation-warning (1.275V), shutdown (1.375V), and cool-down (4.3V → 0.5V retry)-but latches off permanently until SHDN reset per LT4363-1 specification.

Key Specifications

Pinout & Package

LT4363HDE-1#PBF uses a 12-lead (4mm × 3mm) plastic DFN package with exposed thermal pad (pin 13 = GND, optional PCB connection). Pinout matches LT4363-1 DE package configuration.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LT4363HDE-2#PBF, the LT4363HDE-1#PBF provides deterministic fault containment via latch-off behavior, while TPS26631RHFR trades configurability for integration-making LT4363HDE-1#PBF optimal for high-reliability, thermally demanding, or highly customized surge protection.

Availability

LT4363HDE-1#PBF is available at Aetrix Electronics and suitable for avionic power distribution, industrial PLC backplane protection, and automotive under-hood ECUs requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LT4363HDE-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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving precision instrumentation, industrial automation, communications, and aerospace markets.

The LT4363 product line delivers high-voltage surge protection with intelligent MOSFET gate control, designed specifically for mission-critical power systems requiring robust transient immunity, wide temperature operation, and configurable fault response.

FAQ

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

The LT4363HDE-1#PBF implements latch-off fault behavior: once the MOSFET shuts down due to overvoltage or overcurrent, it remains off until the SHDN pin is pulsed low for ≥100µs. In contrast, LT4363HDE-2#PBF automatically restarts after cool-down. Both share identical electrical specs, pinout, and package. The LT4363HDE-1#PBF is selected where guaranteed fault isolation is required.

How does the LT4363HDE-1#PBF achieve reverse input protection to –60V?

The LT4363HDE-1#PBF achieves –60V reverse input protection through ruggedized input structures on VCC and SHDN pins, rated per Absolute Maximum Ratings. When VCC is pulled below GND, internal protection diodes and circuitry prevent latch-up or damage. This eliminates need for external series diodes in battery-reversal-prone applications like automotive or portable equipment.

Can the LT4363HDE-1#PBF regulate output voltage to a specific value like 24V?

Yes. The LT4363HDE-1#PBF regulates output voltage using the FB pin servo loop, which maintains 1.275V at FB. A resistive divider from OUT to GND sets the clamp voltage: V_CLAMP = 1.275V × (1 + R1/R2). For 24V output, use R1 = 178kΩ and R2 = 10kΩ (standard 1% values). The LT4363HDE-1#PBF actively controls the external MOSFET gate to hold this voltage during transients.

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

The LT4363HDE-1#PBF requires a minimum 10nF capacitor on the TMR pin to ensure loop stability and proper fault timing. Smaller values risk oscillation or inaccurate timing; larger values extend warning and shutdown delays linearly. For example, a 6.8µF capacitor yields ~97ms total fault timer (t_FLT) and ~17ms warning period (t_WARNING) under typical conditions.

Does the LT4363HDE-1#PBF support back-to-back N-channel MOSFET configurations for reverse polarity protection?

Yes. The LT4363HDE-1#PBF supports back-to-back N-MOSFETs by driving both gates synchronously via GATE output, while UV and OV comparators enforce directional control. This replaces lossy Schottky diodes, reducing forward voltage drop from ~0.4V to <50mV and improving efficiency-especially critical in 12V/24V battery systems where every millivolt matters.