Analog Devices Inc. LT4363CS-1#PBF

Overview

LT4363CS-1#PBF from Analog Devices is a high-voltage surge stopper IC that protects downstream loads by regulating output voltage during transients and limiting current via external N-channel MOSFET control. It features 4V–80V input range, 50mV adjustable current sense threshold, 1.275V FB reference, 12-pin SO package, and latch-off fault behavior (LT4363-1 variant). Used in avionic power rails where sustained overvoltage must trigger irreversible shutdown.

For engineers reviewing the LT4363CS-1#PBF datasheet, LT4363CS-1#PBF pinout, LT4363CS-1#PBF application, or LT4363CS-1#PBF equivalent, key selection criteria include latch-off vs auto-retry behavior, SO-16 thermal performance (θJA = 80°C/W), UV/OV comparator thresholds (1.275V ±12mV), TMR timer configuration for SOA-aware fault timing, and reverse input protection to –60V.

Technical Context

The LT4363CS-1#PBF implements dual-fault protection: overvoltage regulation via FB-servo loop holding OUT at VOUT = 1.275V × (1 + R1/R2), and overcurrent limiting via SNS–OUT differential sensing with 50mV nominal clamp. Fault detection triggers a voltage-dependent TMR capacitor charging current-scaling from ~4µA to 50µA in overvoltage or ~8µA to 260µA in overcurrent-enabling MOSFET safe operating area (SOA) optimization.

As the -1 variant, LT4363CS-1#PBF latches GATE low after TMR reaches 1.375V and remains off until SHDN is pulsed low ≥100µs; it lacks OV pin functionality (pin 15 NC), unlike LT4363-2. Its SO-16 package provides 80°C/W junction-to-ambient thermal resistance and supports operation from 0°C to 70°C ambient.

Key Specifications

Pinout & Package

LT4363CS-1#PBF uses a 16-lead plastic SO package (S package) with 0°C to 70°C operating temperature range. Exposed pad is not present in SO variant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LT4363CS-1#PBF, LT4363HS-1#PBF offers identical electrical behavior with enhanced thermal and reliability specs, while LT4363CS-2#PBF changes fundamental fault-handling semantics-requiring redesign of reset logic and UV/OV monitoring strategy.

Availability

LT4363CS-1#PBF is available at Aetrix Electronics and suitable for avionic power distribution, industrial hot-swap modules, intrinsic safety barriers, and battery-powered medical equipment requiring stable component supply with guaranteed long-term availability.

Supply support for LT4363CS-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 healthcare markets.

The LT4363CS-1#PBF belongs to Analog Devices' surge protection and high-voltage controller product line, designed specifically for ruggedized power system protection in safety-critical and high-reliability applications where latch-off behavior and reverse-input tolerance are mandatory.

FAQ

What is the key functional difference between LT4363CS-1#PBF and LT4363CS-2#PBF?

The LT4363CS-1#PBF implements latch-off fault behavior: once the TMR pin reaches 1.375V, GATE and FLT remain low until SHDN is pulsed low for ≥100µs. In contrast, LT4363CS-2#PBF automatically retries after TMR discharges to 0.5V, and includes a functional OV pin (pin 15) to inhibit retry during sustained overvoltage. These differences make LT4363CS-1#PBF suitable for safety-critical systems requiring manual intervention after fault.

How does the TMR capacitor value affect fault timing in LT4363CS-1#PBF?

In LT4363CS-1#PBF, the TMR capacitor (connected between pin 10 and GND) sets three critical intervals: early warning duration (TMR = 1.275V), total fault time before GATE turn-off (TMR = 1.375V), and required cool-down before reset. For example, a 6.8µF capacitor yields ~96.9ms total regulation time under 75V VDS. The current charging TMR scales with VCC–VOUT, ensuring shorter fault windows at higher stress-directly protecting MOSFET SOA.

Can LT4363CS-1#PBF be used with P-channel MOSFETs?

No. LT4363CS-1#PBF is designed exclusively for N-channel MOSFETs configured as high-side switches, with GATE drive referenced to OUT and capable of delivering ~13V above OUT. Its internal charge pump and gate control architecture do not support P-channel configurations. Using a P-MOSFET would require external level-shifting circuitry and invalidate all timing, current limit, and regulation functions specified for LT4363CS-1#PBF.

What is the maximum reverse voltage LT4363CS-1#PBF can withstand on the VCC pin?

The LT4363CS-1#PBF absolute maximum rating for VCC is –60V, meaning it can safely withstand up to 60V reverse polarity on the input supply without damage. This capability enables use in automotive and battery-powered systems where accidental battery reversal or inductive kickback could occur. The SHDN, UV, and OV pins also tolerate –60V, but note that OV is NC in the -1 variant.

Does LT4363CS-1#PBF provide reverse current blocking when the MOSFET is off?

LT4363CS-1#PBF itself does not block reverse current; it relies on the external N-channel MOSFET's body diode. However, back-to-back N-MOSFET configurations can be implemented using a second LT4363CS-1#PBF or discrete control to achieve active reverse blocking-eliminating the 0.3V–0.7V drop of a Schottky diode. The datasheet explicitly recommends this topology for reducing voltage loss and power dissipation in reverse-protection applications.