Analog Devices Inc. LTC4366HDDB-2#TRMPBF

Overview

LTC4366HDDB-2#TRMPBF from Analog Devices is a high-voltage surge stopper IC that controls an external N-channel MOSFET to regulate output voltage during overvoltage transients up to >500V. It features auto-retry fault recovery, adjustable 1.23V FB reference, 9-second internal cool-down timer, and operates across –40°C to 125°C. Used in 28V vehicle systems to maintain uninterrupted load operation while clamping surges at 43V.

For engineers reviewing the LTC4366HDDB-2#TRMPBF datasheet, LTC4366HDDB-2#TRMPBF pinout, LTC4366HDDB-2#TRMPBF application, or LTC4366HDDB-2#TRMPBF equivalent, key selection criteria include its floating topology support, VSS-referenced TIMER pin timing (311 ms/µF), shutdown quiescent current <14 µA, and compatibility with high-voltage DC distribution architectures requiring robust transient immunity.

Technical Context

The LTC4366HDDB-2#TRMPBF implements a floating architecture where OUT powers internal circuitry-including the charge pump and overvoltage regulation amplifier-enabling operation with input voltages far exceeding its own pin ratings. Its regulation loop compares FB voltage to a 1.23V reference referenced to OUT, enabling precise clamp voltage setting via external resistor dividers.

It uses dual shunt regulators (12V on VDD, 5.7V on OUT) and a 9µA TIMER pin current source to implement adjustable overvoltage protection timing. The LTC4366-2 variant auto-retries after a 9-second cool-down period following fault latching, unlike the latch-off LTC4366-1 version.

Key Specifications

Pinout & Package

Package: 8-lead (3mm × 2mm) plastic DFN with exposed thermal pad (Pin 9), rated TJMAX = 150°C and θJA = 75°C/W when VSS is soldered to PCB.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC4366IDDB-2#TRMPBF and LTC4366HDDB-1#TRMPBF, the LTC4366HDDB-2#TRMPBF uniquely combines extended temperature operation (–40°C to 125°C) with autonomous recovery-making it the sole option for high-reliability, maintenance-free surge protection in harsh mobile environments.

Availability

LTC4366HDDB-2#TRMPBF is available at Aetrix Electronics and suitable for 28V vehicle systems, avionic DC distribution, and industrial high-voltage power supplies requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LTC4366HDDB-2#TRMPBF 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, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving precision instrumentation, industrial, automotive, and aerospace markets.

The LTC4366 family is designed specifically for high-voltage floating surge protection-enabling reliable operation in >500V transient environments using low-cost external N-MOSFETs and passive components.

FAQ

What is the maximum input voltage the LTC4366HDDB-2#TRMPBF can protect against?

The LTC4366HDDB-2#TRMPBF itself does not have a fixed maximum input voltage limit-the device floats with the supply via external resistors (RSS, RIN) and relies on the external N-MOSFET's breakdown rating. Application circuits have demonstrated reliable operation with >500V transients, constrained only by MOSFET VDS(max) and resistor voltage ratings. The LTC4366HDDB-2#TRMPBF's internal pins remain protected by its 12V (VDD) and 5.7V (OUT) shunt regulators.

How does the LTC4366HDDB-2#TRMPBF differ from the LTC4366HDDB-1#TRMPBF?

The LTC4366HDDB-2#TRMPBF implements auto-retry behavior: after an overvoltage fault, it enters a 9-second cool-down period and then automatically resumes normal operation. In contrast, the LTC4366HDDB-1#TRMPBF latches off permanently until the SD pin is actively toggled low-then-high. Both share identical pinout, temperature range (–40°C to 125°C), and package (DDB).

What is the purpose of the BASE pin on the LTC4366HDDB-2#TRMPBF?

The BASE pin on the LTC4366HDDB-2#TRMPBF drives the base of an external PNP transistor used to reduce power dissipation in the RSS resistor. By sourcing ~0.8 µA and enabling PNP current gain (β), it allows RSS values up to ~35× larger than in non-PNP configurations-reducing physical size and thermal stress in high-voltage floating topologies where RSS drops hundreds of volts.

Can the LTC4366HDDB-2#TRMPBF be used without an external MOSFET?

No-the LTC4366HDDB-2#TRMPBF is a controller IC and requires an external N-channel MOSFET to function. It provides gate drive (up to 12V above OUT), regulation feedback (via FB), and fault timing (via TIMER), but has no internal power switch. The MOSFET serves as the series pass element that absorbs overvoltage energy; selecting appropriate RDS(on), Qg, and SOA is essential for reliable operation.

What is the minimum supply voltage required to start up the LTC4366HDDB-2#TRMPBF?

The minimum startup supply voltage for the LTC4366HDDB-2#TRMPBF depends on external component values. Using typical design values (RIN = 324kΩ, RSS = 46.4kΩ, VTH ≈ 3V, Schottky drop ≈ 0.58V), the calculated minimum is ~22V. This ensures sufficient current to charge C1 to the 4.75V UVLO2 threshold before the charge pump engages. Lower VIN risks incomplete startup and MOSFET overheating during ramp-up.