Analog Devices Inc. LT4363IDE-1#PBF

Overview

LT4363IDE-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, limits current via 50mV SNS–OUT sense threshold, and latches off after fault timeout. It operates from 4V to 80V input, supports –60V reverse input protection, and targets industrial power systems requiring robust overvoltage/overcurrent fault management.

For engineers reviewing the LT4363IDE-1#PBF datasheet, LT4363IDE-1#PBF pinout, LT4363IDE-1#PBF application, or LT4363IDE-1#PBF equivalent, key selection criteria include latch-off behavior (LT4363-1), adjustable 1.275V UV/OV thresholds, 7µA shutdown current, TMR-based adaptive fault timing, and DFN-12 (4mm × 3mm) package compatibility with thermal pads.

Technical Context

The LT4363IDE-1#PBF implements dual-loop protection: a voltage amplifier regulates GATE to hold FB at 1.275V during overvoltage, while a current amplifier limits ΔVSNS to 50mV (25mV if OUT < 2V) during overcurrent. Fault detection triggers a TMR capacitor charging sequence with voltage-dependent current scaling-rising from ~4µA at VDS ≤ 0.5V to 50µA at VDS = 75V for overvoltage, and up to 260µA for overcurrent.

It features precision comparators for UV (1.275V threshold, 12mV hysteresis) and OV (1.275V threshold, 7.5mV hysteresis), a 14V GATE clamp, and SHDN pin tolerance from –60V to 100V. The LT4363-1 variant latches GATE low after fault timeout and requires active reset via SHDN pulse ≥100µs, distinguishing it from auto-retry LT4363-2 versions.

Key Specifications

Pinout & Package

LT4363IDE-1#PBF uses a 12-lead (4mm × 3mm) plastic DFN package with exposed thermal pad (Pin 13) connected to GND. The package supports high-power dissipation (θJA = 43°C/W) and is rated for industrial temperature range.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC4365IMS-2#PBF and TPS26631RGER, LT4363IDE-1#PBF offers unique latch-off behavior for fail-safe systems, user-adjustable clamp voltage via FB, and –60V reverse input capability-making it irreplaceable in avionics and intrinsic safety applications demanding deterministic fault handling.

Availability

LT4363IDE-1#PBF is available at Aetrix Electronics and suitable for avionic power protection, industrial hot-swap systems, intrinsic safety barriers, and battery-powered telematics requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LT4363IDE-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 for precision engineering applications.

The LT4363 family was designed specifically for high-reliability industrial and aerospace power systems requiring robust, adaptive overvoltage and overcurrent protection with latch-off safety behavior.

FAQ

What is the function of the TMR pin on the LT4363IDE-1#PBF?

The TMR pin on the LT4363IDE-1#PBF connects to an external capacitor that sets three timing intervals: early fault warning (at 1.275V), MOSFET turn-off (at 1.375V), and cool-down period (to 0.5V). Its charging current scales with VDS (VCC–OUT), enabling adaptive fault timing that optimizes MOSFET safe operating area. For LT4363IDE-1#PBF (LT4363-1 variant), the GATE remains latched off after reaching 1.375V until SHDN is pulsed.

How does the LT4363IDE-1#PBF differ from the LT4363-2 variants?

The LT4363IDE-1#PBF implements LT4363-1 behavior: it latches GATE and FLT low after fault timeout and requires an active SHDN reset pulse (≤0.4V for ≥100µs). In contrast, LT4363-2 variants automatically restart once TMR discharges to 0.5V. This makes LT4363IDE-1#PBF suitable for safety-critical systems where uncontrolled retries are prohibited.

Can the LT4363IDE-1#PBF protect against reverse battery connections?

Yes - the LT4363IDE-1#PBF tolerates –60V on VCC, SHDN, UV, and OV pins without damage. When used with back-to-back N-channel MOSFETs, it enables efficient reverse-input protection with near-zero forward voltage drop, eliminating the power loss and thermal issues associated with Schottky diodes.

What is the purpose of the ENOUT pin on the LT4363IDE-1#PBF?

The ENOUT pin on the LT4363IDE-1#PBF is an open-collector enable output that goes high-impedance when the external MOSFET is fully enhanced (VOUT within 0.5V of VCC and >3V above GND). It provides system-level status feedback to microcontrollers or supervisors, indicating healthy pass transistor conduction without requiring additional sensing circuitry.

Does the LT4363IDE-1#PBF require external components to set overvoltage clamp voltage?

Yes - the LT4363IDE-1#PBF uses the FB pin to regulate output voltage during overvoltage events. A resistor divider between OUT and GND sets the clamp point based on the internal 1.275V reference. For example, a 27V clamp requires R1/R2 = 20.1, enabling precise, application-specific protection without trimming or calibration.