Analog Devices Inc. LTC4380CMS-2#PBF

Overview

LTC4380CMS-2#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, input overvoltage (up to 250Vpk), and overcurrent events. It features fixed 31.5V/50V gate clamp selection via SEL pin, 8µA operating supply current, and auto-retry fault behavior. Used in 12V/24V automotive power rails where sustained surge immunity and battery-backed operation are required.

For engineers reviewing the LTC4380CMS-2#PBF datasheet, LTC4380CMS-2#PBF pinout, LTC4380CMS-2#PBF application, or LTC4380CMS-2#PBF equivalent, key selection criteria include gate clamp voltage configuration (SEL = GND → 31.5V), TMR capacitor-based fault timing, reverse input protection to –60V, latchoff vs. auto-retry behavior, and compatibility with high-voltage N-channel MOSFETs up to 72V input.

Technical Context

The LTC4380CMS-2#PBF implements a multiplier-based fault timer that generates TMR pin current proportional to both V_DS (via DRN pin) and I_D (via SNS–OUT differential voltage), enabling MOSFET stress–adaptive turn-off timing. Its internal 20µA charge pump regulates GATE to V_OUT + 11.5V during normal conduction, while clamping GATE to 31.5V (SEL = GND) or 50V (SEL = V_CC) during overvoltage.

Unlike latchoff variants (e.g., LTC4380CMS-1), the -2 version enters a cool-down phase after fault detection: TMR discharges to 100mV across 15 cycles before automatic restart, with retry duty cycle as low as 0.1% under heavy overvoltage. The ON pin serves dual function-undervoltage lockout (1.05V threshold) and shutdown control-reducing quiescent current to 6µA when pulled low.

Key Specifications

Pinout & Package

10-Lead Plastic MSOP package (MS grade), exposed pad optional for thermal relief. Pin 1 = GND (exposed pad tied to GND).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC4380IMS-2#PBF and LTC4380HMS-2#PBF, the LTC4380CMS-2#PBF offers identical surge stopper architecture and auto-retry behavior but targets cost-sensitive commercial-temperature applications-making it optimal for dashboard electronics, body control modules, and non-critical industrial interfaces where 0°C to 70°C operation is sufficient.

Availability

LTC4380CMS-2#PBF is available at Aetrix Electronics and suitable for automotive load dump protection, always-on battery-powered systems, and industrial 24V DC distribution requiring stable component supply and long-term manufacturing continuity.

Supply support for LTC4380CMS-2#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 designs precision analog, mixed-signal, and digital signal processing ICs for industrial, automotive, communications, and healthcare applications.

The LTC4380 product line delivers robust, low-quiescent-current surge protection for high-reliability power rails-specifically engineered to replace discrete crowbar circuits and simplify compliance with ISO 7637-2 and ISO 16750-2 automotive transient standards.

FAQ

What is the gate clamp voltage configuration for LTC4380CMS-2#PBF?

The LTC4380CMS-2#PBF supports two fixed gate clamp voltages: 31.5V when the SEL pin is grounded, and 50V when SEL is tied to V_CC. This directly determines the output overvoltage limit-approximately 27V or 45V respectively-based on the external MOSFET's threshold voltage. The LTC4380CMS-2#PBF does not support adjustable clamping; that capability is reserved for LTC4380-3/-4 variants.

How does LTC4380CMS-2#PBF differ from LTC4380CMS-1#PBF?

The LTC4380CMS-2#PBF implements auto-retry fault behavior: after overvoltage or overcurrent shutdown, it enters a cool-down phase and automatically restarts once the TMR pin discharges to 100mV. In contrast, the LTC4380CMS-1#PBF latches off permanently until power is cycled or the ON pin is pulsed low for ≥100µs. Both share identical gate clamp options and electrical specs.

Can LTC4380CMS-2#PBF drive back-to-back N-MOSFETs for reverse polarity protection?

Yes-the GATE pin of LTC4380CMS-2#PBF can drive stacked N-channel MOSFETs with sources tied together, enabling true reverse-input protection down to –60V without Schottky diode voltage drop or thermal loss. This configuration eliminates the 0.3–0.5V forward drop and associated heat generation of diode-based solutions, improving efficiency in battery-critical applications.

What is the minimum TMR capacitor value recommended for LTC4380CMS-2#PBF?

Analog Devices recommends a minimum 10V-rated X7R ceramic capacitor for the TMR pin of LTC4380CMS-2#PBF to ensure stable timing across temperature and voltage. While no absolute minimum capacitance is specified, typical designs use 100nF to 10µF; the 8.2µF value shown in the 12V/1A reference design provides ~100ms fault timeout and ~1.5s cool-down before retry. Smaller values reduce timing margin but improve response speed.

Does LTC4380CMS-2#PBF require external components for stability?

Yes-LTC4380CMS-2#PBF requires a 47nF capacitor and 33Ω series resistor at the GATE pin to compensate the current limit amplifier loop, as specified in the datasheet. Additionally, the OUT pin must be bypassed with ≥22µF low-ESR capacitance placed adjacent to the pin. Omitting these compromises stability, causing oscillation or delayed current limiting during fast transients.