Analog Devices Inc. LT4363CDE-2#PBF

Overview

LT4363CDE-2#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 100V, limits current via 50mV SNS–OUT sense threshold, and implements adjustable fault timing with automatic retry (LT4363-2 variant). It operates from 4V to 80V input, supports reverse input protection to –60V, and targets industrial power rail protection.

For engineers reviewing the LT4363CDE-2#PBF datasheet, LT4363CDE-2#PBF pinout, LT4363CDE-2#PBF application, or LT4363CDE-2#PBF equivalent, key selection criteria include its 12-lead DFN (4mm × 3mm) package, 0°C to 70°C temperature grade, 1.275V FB reference, 5µs overcurrent turn-off propagation, and distinct LT4363-2 auto-restart behavior versus LT4363-1 latch-off.

Technical Context

The LT4363CDE-2#PBF integrates dual precision comparators for UV/OV monitoring (1.275V thresholds), a charge-pump-based GATE driver capable of +13V above OUT, and a fault timer whose charging current scales with V_CC–V_OUT to optimize MOSFET safe operating area (SOA) utilization during overvoltage or overcurrent events.

Unlike the LT4363-1, the LT4363-2 variant features automatic restart after cool-down: upon TMR falling to 0.5V, GATE pulls high without external reset, while OV comparator input (present only in -2 versions) inhibits retry if input remains overvoltage - preventing motorboating under sustained surges.

Key Specifications

Pinout & Package

LT4363CDE-2#PBF is housed in a 12-lead plastic DFN package (4mm × 3mm) with exposed thermal pad (Pin 13, connected to GND). The package supports high-power dissipation (θ_JA = 43°C/W) and is RoHS-compliant with lead-free finish (#PBF).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC4365 and TPS26631, the LT4363CDE-2#PBF delivers wider input range (4V–80V), precise adjustable output clamping, V_DS-adaptive fault timing, and true high-side N-MOSFET control - making it uniquely suitable for demanding avionics, heavy-industry, and intrinsic safety designs.

Availability

LT4363CDE-2#PBF is available at Aetrix Electronics and suitable for avionic power bus protection, industrial PLC I/O modules, hot-swap board insertion, and intrinsic safety barrier supply requiring stable component supply across extended production lifecycles.

Supply support for LT4363CDE-2#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 precision instrumentation, industrial automation, aerospace, and communications markets.

The LT4363 product line was designed specifically for high-reliability power rail protection in harsh environments - delivering robust surge suppression, adaptive fault management, and seamless integration with discrete N-MOSFETs for scalable current handling.

FAQ

What is the key functional difference between LT4363CDE-2#PBF and LT4363CDE-1#PBF?

The LT4363CDE-2#PBF implements automatic restart after fault cool-down: once the TMR pin voltage falls to 0.5V, the GATE pin pulls high without external intervention. In contrast, the LT4363CDE-1#PBF latches off permanently and requires a SHDN pin pulse (≥100µs low) to reset. This makes the LT4363CDE-2#PBF ideal for unattended systems needing autonomous recovery from transient overvoltage or overcurrent events.

How does the LT4363CDE-2#PBF achieve V_DS-adaptive fault timing?

The LT4363CDE-2#PBF measures the voltage difference between VCC and OUT pins to infer V_DS across the external MOSFET. Its internal current source charges the TMR capacitor at a rate proportional to this difference - e.g., ~4µA at V_DS ≤ 0.5V rising to ~50µA at V_DS = 75V. This ensures shorter fault durations under high-stress conditions, keeping the MOSFET within its safe operating area without requiring complex external compensation.

Can the LT4363CDE-2#PBF be used with P-channel MOSFETs?

No - the LT4363CDE-2#PBF is explicitly designed to drive N-channel MOSFETs in high-side configuration. Its GATE driver provides a voltage referenced to the OUT (source) node and can swing up to +13V above OUT. Driving a P-channel device would require source-referenced negative gate drive or level-shifting circuitry not supported by the LT4363CDE-2#PBF architecture.

What is the minimum TMR capacitor value required for stable operation of LT4363CDE-2#PBF?

A minimum 10nF capacitor is required on the TMR pin to ensure loop stability and proper fault timing behavior. Smaller values may cause oscillation or erratic FLT assertion. For typical 100ms overvoltage ride-through, a 6.8µF capacitor is commonly used - yielding ~1.275V warning threshold in ~86ms and 1.375V shutdown at ~97ms under V_DS = 20V conditions.

Does the LT4363CDE-2#PBF provide reverse polarity protection natively?

The LT4363CDE-2#PBF itself does not block reverse current, but it enables robust reverse input protection by supporting back-to-back N-channel MOSFET configurations. When paired with a second N-MOSFET oriented opposite the main pass device, the combination replaces a Schottky diode - eliminating its 0.3–0.5V forward drop and associated power loss, while withstanding –60V reverse input without damage to the LT4363CDE-2#PBF.