Analog Devices Inc. LTC4380CMS-4#TRPBF

Overview

LTC4380CMS-4#TRPBF 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 polarity, and overcurrent events. It features 8µA operating current, 4V–72V input range, adjustable gate clamp (via external Zener), auto-retry fault behavior, and integrated MOSFET stress acceleration via TMR pin current proportional to V_DS × I_D. Used in 12V/24V automotive power rails with up to 250V transient suppression.

For engineers reviewing the LTC4380CMS-4#TRPBF datasheet, LTC4380CMS-4#TRPBF pinout, LTC4380CMS-4#TRPBF application, or LTC4380CMS-4#TRPBF equivalent, key selection criteria include its auto-retry fault response, reverse input protection to –60V, 10-pin MSOP package, AEC-Q100 qualification for automotive use, and compatibility with externally adjustable gate clamping for flexible output voltage limiting.

Technical Context

The LTC4380CMS-4#TRPBF implements a multiplier-based fault timer where TMR pin current scales with both MOSFET V_DS (sensed at DRN) and load current (sensed as ΔV_SNS), enabling dynamic SOA protection. Its GATE driver delivers regulated 11.5V above OUT and supports back-to-back MOSFET configurations for reverse input protection without Schottky diode losses.

This variant (–4 suffix) provides externally adjustable gate clamp voltage - no internal 31.5V/50V clamp - relying instead on external Zener clamping at VCC to set GATE limit. It uses auto-retry fault recovery: after TMR reaches 1.215V and shuts off the MOSFET, it enters a cool-down phase with 2µA TMR pull-up/pull-down before automatic restart.

Key Specifications

Pinout & Package

Package: 10-Lead Plastic MSOP (3mm × 3mm footprint, 0.5mm pitch, exposed pad optional). Pinout validated per Analog Devices LTC4380 Rev. C datasheet (MS package top view).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC4380CMS-4#TRPBF, the IMS-4 and HMS-4 variants offer identical surge protection architecture and auto-retry behavior but extend operational reliability into higher ambient temperatures - critical for under-hood deployment where thermal derating of the C-grade part would compromise fault timing accuracy and MOSFET SOA margins.

Availability

LTC4380CMS-4#TRPBF is available at Aetrix Electronics and suitable for automotive load dump protection, reverse battery protection, and always-on telematics modules requiring stable component supply across production lifecycles.

Supply support for LTC4380CMS-4#TRPBF 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 LTC4380 series is designed specifically for robust, low-power surge protection in automotive and industrial power systems - emphasizing ultra-low IQ, AEC-Q100 compliance, and intelligent MOSFET stress management.

FAQ

What is the key functional difference between LTC4380CMS-4#TRPBF and LTC4380CMS-2#TRPBF?

The LTC4380CMS-4#TRPBF uses externally adjustable gate clamping (no internal 31.5V/50V clamp), requiring a Zener diode on VCC to set output voltage limit. In contrast, LTC4380CMS-2#TRPBF has fixed internal clamps selectable via SEL pin. Both share auto-retry fault behavior, but only the –4 version supports custom clamping voltages from ~18V to 86V.

Can LTC4380CMS-4#TRPBF be used without an external Zener diode?

No - LTC4380CMS-4#TRPBF lacks internal gate-to-ground clamping. Without an external Zener on VCC, the GATE pin is only limited to VCC + 13.5V, which may exceed MOSFET ratings during transients. A properly selected Zener (e.g., 27V for 12V systems) is mandatory to define safe output clamping and protect the external MOSFET.

What is the minimum recommended CTMR value for reliable auto-retry operation in LTC4380CMS-4#TRPBF?

Analog Devices specifies a minimum 100nF for CTMR, but 8.2µF is recommended for standard 12V/1A load dump applications. The capacitor must be X7R dielectric with ≥10V rating to ensure stable timing across temperature and voltage. Smaller values reduce fault timeout and cool-down duration, risking premature retry under sustained stress.

Does LTC4380CMS-4#TRPBF support reverse input protection without additional components?

Yes - LTC4380CMS-4#TRPBF supports reverse input protection to –60V with no external diodes required. When used with back-to-back N-MOSFETs, it blocks reverse current while maintaining low forward conduction loss. The ON pin's –60V tolerance and internal circuitry enable direct connection to reversed battery inputs.

How does the TMR pin current scale with MOSFET stress in LTC4380CMS-4#TRPBF?

In LTC4380CMS-4#TRPBF, TMR pin current is generated by an internal multiplier proportional to both V_DS (measured at DRN relative to OUT) and I_D (derived from ΔV_SNS). This results in current scaling with instantaneous MOSFET power dissipation (V_DS × I_D), causing faster TMR charging and shorter fault timeouts under high-stress conditions - preserving SOA.