Analog Devices Inc. LT4363CDE-1#PBF

Overview

LT4363CDE-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, and features latch-off fault behavior with 1.275V FLT warning threshold and 4V–80V operating input range. It is used in avionic power rails requiring sustained operation under 80V surges.

For engineers reviewing the LT4363CDE-1#PBF datasheet, LT4363CDE-1#PBF pinout, LT4363CDE-1#PBF application, or LT4363CDE-1#PBF equivalent, key selection criteria include its 12-lead DFN (4mm × 3mm) package, -1 latch-off reset behavior, 0°C to 70°C temperature grade, adjustable UV/OV thresholds, and reverse input protection down to –60V.

Technical Context

The LT4363CDE-1#PBF implements dual-fault protection: overvoltage regulation via FB-servo loop holding 1.275V at feedback pin, and overcurrent limiting via 50mV (reduced to 25mV when OUT < 2V) SNS–OUT differential sensing. Fault timing is dynamically scaled by V_CC–V_OUT to match MOSFET SOA constraints.

It integrates precision UV (1.275V threshold, 12mV hysteresis) and OV comparators (OV only on -2 variant), a 14V GATE clamp, 7µA shutdown current, and TMR-based timer with three phases: warning (1.275V), turn-off (1.375V), and cool-down (4.3V → 0.5V). The -1 version latches off until SHDN reset; no auto-retry.

Key Specifications

Pinout & Package

LT4363CDE-1#PBF uses a 12-lead plastic DFN package (4mm × 3mm) with exposed thermal pad connected to GND. Pin numbering follows standard top-view DE package layout.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LT4363CDE-2#PBF, the LT4363CDE-1#PBF provides deterministic latch-off behavior essential for safety-critical systems, while TPS26631PWPR trades configurability for integration-making it suitable only where fixed clamping and faster OCP suffice.

Availability

LT4363CDE-1#PBF is available at Aetrix Electronics and suitable for avionic power distribution, industrial hot-swap modules, and intrinsic safety barriers requiring stable component supply across extended temperature and surge conditions.

Supply support for LT4363CDE-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 industrial, automotive, communications, and aerospace markets.

The LT4363 product line delivers robust front-end protection for high-reliability power systems, designed specifically for environments with severe voltage transients, reverse polarity, and demanding safety certification requirements.

FAQ

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

The LT4363CDE-1#PBF implements latch-off fault behavior: once the TMR pin reaches 1.375V and the MOSFET turns off, it remains off until the SHDN pin is actively pulsed low for ≥100µs. In contrast, the LT4363CDE-2#PBF automatically restarts after TMR discharges to 0.5V during cool-down, provided the OV pin voltage falls below 1.275V. This makes the LT4363CDE-1#PBF appropriate for safety-critical applications where uncontrolled retry is prohibited.

How does the LT4363CDE-1#PBF protect against reverse battery connection?

The LT4363CDE-1#PBF withstands –60V on the VCC pin without damage, enabling direct connection to reversed battery terminals. During reverse polarity, internal protection circuitry blocks conduction path through the external N-channel MOSFET, preventing current flow into the load. No external Schottky diode is required-reducing forward voltage drop, power loss, and board space versus conventional solutions.

What is the minimum TMR capacitor value required for stable operation of LT4363CDE-1#PBF?

The LT4363CDE-1#PBF requires a minimum 10nF capacitor on the TMR pin to ensure loop stability and accurate fault timing. Smaller values may cause oscillation in the gate drive control loop or inconsistent warning/turn-off delays. For typical 100ms surge ride-through, a 6.8µF capacitor is used-as validated in the datasheet's Figure TA01b-and must be low-ESR ceramic or tantalum with ≥10V rating.

Can the LT4363CDE-1#PBF regulate output voltage to a precise value such as 12.0V?

Yes. The LT4363CDE-1#PBF regulates output voltage via the FB pin, which holds 1.275V referenced to GND. Using a resistive divider (e.g., 1kΩ from OUT to FB, 9.53kΩ from FB to GND), the output is set to 12.0V with ±1% accuracy over temperature. The FB input bias current is ±1µA, so divider current should exceed 10µA to minimize error-ensuring stable, accurate regulation without trimming.

Does the LT4363CDE-1#PBF support reverse input protection without additional components?

Yes. The LT4363CDE-1#PBF supports reverse input protection natively: its VCC pin tolerates –60V, and the internal architecture blocks current flow when input polarity is inverted. When paired with back-to-back N-channel MOSFETs (as shown in the datasheet's Figure TA01), it replaces Schottky diodes entirely-eliminating 0.4V forward drop and associated heat, while maintaining full 4V–80V forward operation and –60V reverse survivability.