Analog Devices Inc. LTC4380CDD-4#TRPBF

Overview

LTC4380CDD-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. It is used in 12V/24V automotive power rails requiring robust transient protection.

For engineers reviewing the LTC4380CDD-4#TRPBF datasheet, LTC4380CDD-4#TRPBF pinout, LTC4380CDD-4#TRPBF application, or LTC4380CDD-4#TRPBF equivalent, key selection criteria include its auto-retry latch-reset behavior, absence of internal gate-to-GND clamp (requiring external V_CC clamping), 10-pin DFN (3mm × 3mm) package, AEC-Q100 qualification, and precise 1.215V TMR fault threshold.

Technical Context

The LTC4380CDD-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 clamps to V_CC + 13.5V - no internal gate-to-GND clamp exists, distinguishing it from -1/-2 variants.

It supports reverse input protection to –60V, uses an ON pin comparator for undervoltage detection (1.05V threshold) and shutdown control, and enters cool-down mode upon fault with automatic restart after TMR discharges to 100mV - unlike latch-off versions (-1/-3). Fault timing is set by CTMR capacitance and modulated by real-time MOSFET power dissipation.

Key Specifications

Pinout & Package

Package: 10-lead (3mm × 3mm) plastic DFN with exposed pad (Pin 11 = GND, optional PCB connection).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC4380CDD-2#TRPBF, LTC4380CDD-4#TRPBF trades internal clamp simplicity for external clamping flexibility and precise MOSFET SOA control; versus TPS26631RGER, it offers higher voltage capability (72V vs 60V), lower I_Q (8µA vs 25µA), and adaptive fault timing - critical for high-reliability automotive and industrial systems.

Availability

LTC4380CDD-4#TRPBF is available at Aetrix Electronics and suitable for automotive load dump protection, industrial power rail hardening, and battery-backed always-on systems requiring stable component supply, AEC-Q100 compliance, and long-term lifecycle support.

Supply support for LTC4380CDD-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 family is designed as precision surge stoppers for automotive and industrial power systems, emphasizing ultra-low quiescent current, MOSFET SOA optimization, and robust fault management - with LTC4380CDD-4#TRPBF targeting applications requiring externally adjustable clamping and auto-retry behavior.

FAQ

What is the key functional difference between LTC4380CDD-4#TRPBF and LTC4380CDD-2#TRPBF?

The LTC4380CDD-4#TRPBF has no internal gate-to-GND clamp and relies on external V_CC clamping (e.g., Zener diode) to set output voltage limits, whereas LTC4380CDD-2#TRPBF integrates selectable 31.5V/50V gate clamps. Both share auto-retry behavior, but LTC4380CDD-4#TRPBF offers greater clamping flexibility at the cost of one additional component. This makes LTC4380CDD-4#TRPBF ideal for custom clamp voltages outside the fixed 27V/45V range.

Does LTC4380CDD-4#TRPBF support reverse polarity protection, and how is it implemented?

Yes, LTC4380CDD-4#TRPBF supports reverse input protection to –60V on V_CC, ON, and SEL pins. It achieves this through internal clamping circuitry that safely shunts reverse current without requiring an external Schottky diode. When reverse voltage is applied, the device remains non-conductive and draws only leakage current (<2mA), protecting downstream circuitry while maintaining zero forward voltage drop in normal operation.

How does the fault timer in LTC4380CDD-4#TRPBF respond to varying MOSFET stress levels?

The LTC4380CDD-4#TRPBF's TMR pin current is generated by an internal multiplier proportional to both V_DS (sensed at DRN) and I_D (derived from ΔV_SNS). During high-stress faults - such as sustained overvoltage with heavy load - TMR current increases, causing CTMR to charge faster and reducing fault timeout. This adaptive timing ensures the MOSFET stays within its safe operating area, unlike fixed-timer solutions. The cool-down period after fault also scales with thermal recovery needs.

What is the recommended minimum capacitance for the TMR pin in LTC4380CDD-4#TRPBF, and why?

A minimum 1nF ceramic capacitor is recommended for the TMR pin in LTC4380CDD-4#TRPBF, though typical designs use 1µF–10µF for practical fault timing (e.g., 8.2µF yields ~100ms nominal timeout). The capacitor must be X7R dielectric with ≥10V rating to minimize voltage and temperature coefficient effects. Smaller values increase sensitivity to noise and reduce timing accuracy; larger values extend fault duration unnecessarily and slow auto-retry recovery.

Can LTC4380CDD-4#TRPBF drive back-to-back N-MOSFETs for bidirectional blocking, and what design considerations apply?

Yes, LTC4380CDD-4#TRPBF can drive back-to-back N-MOSFETs for reverse input and output protection by connecting GATE to the common gate node and configuring the MOSFETs source-to-source. Critical considerations include ensuring both MOSFETs share identical characteristics, using matched sense resistors for SNS/OUT, and verifying that V_GS remains within ±20V during transients. The 17V internal GATE-to-OUT clamp protects against gate oxide breakdown during fast edges.