Analog Devices Inc. LT4356IDE-3#TRPBF

Overview

LT4356IDE-3#TRPBF from Analog Devices is a surge protection controller that regulates output voltage during automotive load dump (up to 80V) by driving an external N-channel MOSFET, provides overcurrent protection via 50mV current sense threshold, features adjustable latchoff fault timer with early warning (FLT pin), and operates across –40°C to +85°C in a 12-lead 4mm × 3mm DFN package for high-side battery protection in automotive power systems.

For engineers reviewing the LT4356IDE-3#TRPBF datasheet, LT4356IDE-3#TRPBF pinout, LT4356IDE-3#TRPBF application, or LT4356IDE-3#TRPBF equivalent, key selection considerations include its 4V–80V operating range, –60V reverse input tolerance, 7µA shutdown current, 1.25V FB reference, and fault timer current scaling with V_DS for SOA-optimized MOSFET protection.

Technical Context

The LT4356IDE-3#TRPBF implements dual-loop protection: a voltage amplifier servoing the FB pin to 1.25V during overvoltage events (e.g., 80V transients), and a current amplifier limiting ΔV_SNS = V_CC – V_SNS to 50mV during overcurrent. Its TMR pin charges with a V_DS-dependent current-2µA at 0.5V up to 50µA at 75V (OV) or 260µA at 80V (OC)-enabling adaptive fault timing aligned with MOSFET safe operating area.

It integrates a charge pump delivering 10–16V gate drive above OUT (≥4.5V at V_CC = 4V), supports back-to-back FET reverse polarity protection, and latches GATE off after fault timeout until SHDN is pulsed low (≥100µs) with >10V/ms slew rate. The auxiliary amplifier (AOUT/IN+) functions as a 1.25V-referenced comparator or linear regulator controller.

Key Specifications

Pinout & Package

LT4356IDE-3#TRPBF is housed in a 12-lead 4mm × 3mm plastic DFN package with exposed pad (Pin 13), rated for –40°C to +85°C operation. The exposed pad may be left unconnected or tied to GND for thermal enhancement.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LT4356HDE-3#TRPBF, the LT4356IDE-3#TRPBF offers cost-optimized industrial-temperature performance without automotive qualification overhead; versus LT4356IMS-3#TRPBF, it provides full feature set including auxiliary amplifier and DFN thermal advantage, at the cost of two extra pins.

Availability

LT4356IDE-3#TRPBF is available at Aetrix Electronics and suitable for automotive load dump protection, hot-swap power distribution, and battery-powered system protection requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for LT4356IDE-3#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 precision instrumentation, industrial automation, and automotive markets since 1965.

The LT4356 family is designed as high-voltage surge stoppers for automotive and industrial power systems, emphasizing robust fault handling, MOSFET SOA optimization, and seamless integration with N-channel pass devices.

FAQ

What is the maximum input voltage the LT4356IDE-3#TRPBF can withstand?

The LT4356IDE-3#TRPBF supports continuous operation from 4V to 80V on the VCC pin and can withstand reverse input voltages down to –60V without damage. This rating applies to VCC, SNS, and SHDN pins, making it suitable for harsh automotive environments with load dump and reverse battery conditions. Absolute maximum ratings confirm VCC tolerance up to 100V transiently, but sustained operation must remain within 4V–80V.

How does the LT4356IDE-3#TRPBF implement overcurrent protection?

The LT4356IDE-3#TRPBF monitors the voltage drop between VCC and SNS pins, using an internal amplifier to regulate ΔV_SNS = V_CC – V_SNS to a precise 50mV threshold. When this condition persists beyond the TMR-set timeout, the GATE pin is pulled low by a 10mA sink current. The fault timer current during overcurrent scales with V_DS, reaching up to 260µA at 80V to ensure rapid MOSFET turn-off under high-stress conditions.

Can the LT4356IDE-3#TRPBF drive standard-threshold N-channel MOSFETs?

Yes - the LT4356IDE-3#TRPBF's charge pump delivers a GATE drive voltage of 10V to 16V above the OUT pin when VCC ≥ 8V, which fully enhances standard-threshold N-channel MOSFETs (V_GS(th) ≈ 2–4V). For VCC < 8V (e.g., cold crank at 4V), gate drive drops to ≥4.5V, requiring logic-level MOSFETs with V_GS(th) ≤ 1.8V to ensure reliable turn-on.

What is the purpose of the TMR pin on the LT4356IDE-3#TRPBF?

The TMR pin on the LT4356IDE-3#TRPBF sets the fault timing via an external capacitor to ground. During overvoltage or overcurrent events, a V_DS-scaled current charges this capacitor: 2–50µA (OV) or 4–260µA (OC). At 1.25V, FLT asserts early warning; at 1.35V, GATE turns off. The 100mV window enables predictable warning intervals (e.g., 20ms/µF), allowing system-level backup actions before power loss.

Does the LT4356IDE-3#TRPBF include reverse polarity protection?

The LT4356IDE-3#TRPBF itself does not integrate reverse polarity protection circuitry, but it enables robust implementation using back-to-back N-channel MOSFETs instead of Schottky diodes. Its –60V rating on VCC, SNS, and SHDN pins allows direct connection to reversed battery inputs, and the gate drive architecture supports configuring two N-FETs to block reverse current with minimal voltage drop and no power loss.