Analog Devices Inc. LTC4380IMS-4#PBF

Overview

LTC4380IMS-4#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, 8µA operating current, 50mV current limit threshold, and auto-retry fault behavior. Used in 12V/24V automotive power rails requiring robust transient protection.

For engineers reviewing the LTC4380IMS-4#PBF datasheet, LTC4380IMS-4#PBF pinout, LTC4380IMS-4#PBF application, or LTC4380IMS-4#PBF equivalent, key selection criteria include its –40°C to 85°C industrial temperature grade, MSOP-10 package, auto-retry latchoff timing, adjustable V_GATE clamping via external Zener, and reverse input protection to –60V.

Technical Context

The LTC4380IMS-4#PBF implements a multiplier-based fault timer where TMR pin current scales with both MOSFET V_DS (sensed at DRN) and I_D (via ΔV_SNS), enabling dynamic SOA protection proportional to instantaneous power dissipation. Its GATE driver delivers regulated 11.5V above OUT and supports back-to-back MOSFET configurations for reverse polarity blocking.

This variant (–4) lacks internal gate-to-GND clamp circuitry - gate voltage is limited only by V_CC + 13.5V compliance and externally clamped V_CC, enabling programmable output clamping from ~18V to 86V. Fault response defaults to auto-retry with cool-down cycle governed by CTMR, not latching.

Key Specifications

Pinout & Package

Package: 10-Lead Plastic MSOP (MS package), exposed pad optional for thermal relief. Pin pitch: 0.5mm. Dimensions: 3mm × 3mm × 1.1mm.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC4380IMS-2#PBF and TPS26631RGER, the LTC4380IMS-4#PBF uniquely enables programmable output clamping via external Zener while retaining dynamic MOSFET SOA protection - critical for systems requiring custom voltage limits and high reliability under sustained transients.

Availability

LTC4380IMS-4#PBF is available at Aetrix Electronics and suitable for automotive load dump protection, industrial 24V power rails, battery-powered telematics units, and reverse-battery protected sensor nodes requiring stable component supply and long-term lifecycle support.

Supply support for LTC4380IMS-4#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 LTC4380 product line delivers ultra-low-quiescent-current surge protection ICs designed specifically for automotive and industrial power rails where reliability under extreme transients and battery longevity are critical.

FAQ

What is the function of the SEL pin on the LTC4380IMS-4#PBF?

The SEL pin is unused in the LTC4380IMS-4#PBF. As a -4 variant, this device has no internal gate-to-GND clamp, so SEL is internally tied to GND and plays no functional role. Gate clamping is implemented exclusively via external Zener diode on the VCC pin, enabling fully adjustable output voltage limiting. This differs from LTC4380IMS-1#PBF or LTC4380IMS-2#PBF, where SEL selects between 31.5V and 50V internal clamp voltages.

How does the LTC4380IMS-4#PBF achieve adjustable overvoltage clamping?

The LTC4380IMS-4#PBF achieves adjustable overvoltage clamping by removing the internal gate-to-GND clamp and relying solely on external Zener diode regulation at the VCC pin. Since the GATE pin is limited to VCC + 13.5V, clamping VCC at a chosen voltage (e.g., 40V) directly sets the maximum GATE voltage (53.5V), thereby defining the output clamp point (≈ V_GATE – V_TH). This allows precise, application-specific output limits from ~18V to 86V without modifying the IC.

What is the recommended minimum capacitance for the OUT pin on the LTC4380IMS-4#PBF?

The recommended minimum capacitance for the OUT pin on the LTC4380IMS-4#PBF is 22µF, placed as close as possible to the pin. This bulk capacitor stabilizes the output during fast load transients and ensures proper operation of the current sense amplifier. Ceramic or low-ESR tantalum types are preferred; placement proximity minimizes inductive ringing and improves fault response fidelity during overcurrent events.

Does the LTC4380IMS-4#PBF support reverse input protection, and how is it implemented?

Yes, the LTC4380IMS-4#PBF supports reverse input protection to –60V on the VCC pin. It implements this by integrating robust internal ESD structures and rail-to-rail input stage design - no external components are required. When VCC is pulled below GND, internal circuitry remains functional and non-damaging, allowing safe operation during reverse battery connection in automotive applications without added diodes or FETs.

What fault behavior does the LTC4380IMS-4#PBF exhibit during overvoltage or overcurrent events?

The LTC4380IMS-4#PBF exhibits auto-retry fault behavior: upon reaching the 1.215V TMR threshold, it turns off the external MOSFET and pulls FLT low, then enters a cool-down phase where TMR discharges and recharges cyclically. After 15 cycles, when TMR falls below 100mV, the device automatically restarts. This eliminates latching and enables autonomous recovery - ideal for remote or inaccessible systems where manual reset is impractical.