Analog Devices Inc. LTC4380CMS-3#PBF

Overview

LTC4380CMS-3#PBF from Analog Devices is a low-quiescent-current surge stopper IC that controls an external N-channel MOSFET to protect downstream loads from automotive load dump, reverse input, overvoltage (up to 72V input), and overcurrent events. It features adjustable gate clamp voltage (externally set via VCC Zener), 8µA operating current, latchoff fault behavior, and operates from 4V to 72V input. Used in 12V/24V automotive power rails requiring robust transient protection.

For engineers reviewing the LTC4380CMS-3#PBF datasheet, LTC4380CMS-3#PBF pinout, LTC4380CMS-3#PBF application, or LTC4380CMS-3#PBF equivalent, key selection criteria include its latchoff fault response, absence of internal gate-to-GND clamp, reliance on external VCC clamping for output voltage limiting, and compatibility with high-voltage N-channel MOSFETs in hot-swap and battery-powered systems.

Technical Context

The LTC4380CMS-3#PBF implements MOSFET stress-aware fault timing using a multiplier circuit that generates TMR pin current proportional to both V_DS (via DRN pin) and I_D (via SNS–OUT differential voltage), enabling dynamic SOA protection. Its GATE driver delivers regulated 11.5V above OUT with no internal gate-to-GND clamp - unlike -1/-2 variants - requiring external Zener clamping at VCC to define output voltage limit.

It uses an ON pin comparator with 1.05V threshold and 45mV hysteresis for undervoltage detection and shutdown control, reducing quiescent current to 6µA in shutdown. The FLT pin provides open-drain fault indication, and the SEL pin is internally tied to GND for fixed configuration in the -3 variant.

Key Specifications

Pinout & Package

Package: 10-Lead Plastic MSOP (3mm × 3mm footprint, 0.5mm pitch, exposed pad). Thermal resistance θ_JA = 160°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC4380IMS-3#PBF and LTC4380HMS-3#PBF, the LTC4380CMS-3#PBF offers identical surge protection functionality and adjustable gate clamp architecture but is optimized for cost-sensitive commercial-temperature applications where ambient stays below 70°C - making it ideal for dashboard displays, body control modules, and non-under-hood electronics.

Availability

LTC4380CMS-3#PBF is available at Aetrix Electronics and suitable for automotive load dump protection, hot-swap power insertion, reverse battery protection, and industrial 24V power distribution requiring stable component supply across production lifecycles.

Supply support for LTC4380CMS-3#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 industrial, automotive, communications, and healthcare markets.

The LTC4380 product line delivers robust, low-quiescent-current surge protection ICs designed specifically for automotive and industrial power rails where reliability under voltage transients and reverse polarity is mission-critical.

FAQ

What is the key functional difference between LTC4380CMS-3#PBF and LTC4380CMS-1#PBF?

The LTC4380CMS-3#PBF lacks internal gate-to-GND clamp circuitry and relies on external Zener clamping at the VCC pin to define output voltage limit, whereas LTC4380CMS-1#PBF integrates selectable 31.5V/50V internal clamps. This makes the -3 variant more flexible for custom clamp voltages but requires careful Zener selection and layout. Both share identical pinout, latchoff behavior, and MSOP package.

Does LTC4380CMS-3#PBF support auto-retry after a fault?

No. The LTC4380CMS-3#PBF implements latchoff fault behavior: once tripped by overvoltage or overcurrent, the MOSFET remains off until the ON pin is pulled low for at least 100µs or power is cycled. Auto-retry is exclusive to -2 and -4 variants. This design prevents uncontrolled restart attempts during persistent faults - a requirement for many automotive safety domains.

What external components are mandatory for basic operation of LTC4380CMS-3#PBF?

Four components are mandatory: (1) An external N-channel MOSFET (e.g., FDB33N25), (2) a current sense resistor (RSNS) connecting SNS to OUT, (3) a timing capacitor (CTMR) from TMR to GND, and (4) a Zener diode from VCC to GND to set the output clamp voltage. Additionally, ≥22µF ceramic capacitor at OUT and ≥47nF + 33Ω RC network at GATE are required for stability.

Can LTC4380CMS-3#PBF be used in reverse-battery configurations?

Yes. The LTC4380CMS-3#PBF supports –60V on the VCC pin with no damage, enabling direct connection to reverse-connected batteries. When paired with back-to-back N-MOSFETs (driven via GATE and reverse-biased configuration), it achieves true reverse-polarity protection with near-zero forward voltage drop - eliminating Schottky diode losses and thermal issues in battery-powered systems.

How does the fault timer in LTC4380CMS-3#PBF respond to varying MOSFET stress levels?

The LTC4380CMS-3#PBF's fault timer uses a multiplier circuit that sources TMR pin current proportional to both V_DS (measured at DRN) and I_D (derived from ΔV_SNS). During light overvoltage, TMR charges slowly; during heavy overcurrent or high V_DS, current increases significantly - shortening the timeout period. This ensures faster shutdown under high-power-dissipation conditions, keeping the MOSFET within its safe operating area.