Analog Devices Inc. LTC4366CDDB-2#TRMPBF

Overview

LTC4366CDDB-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 from 9V to >500V input with 0°C to 70°C temperature range. It is used in 28V vehicle systems to maintain uninterrupted load operation during 250V surges.

For engineers reviewing the LTC4366CDDB-2#TRMPBF datasheet, LTC4366CDDB-2#TRMPBF pinout, LTC4366CDDB-2#TRMPBF application, or LTC4366CDDB-2#TRMPBF equivalent, key selection criteria include its auto-retry behavior (vs latch-off), floating topology support, 12V gate drive above OUT, 1.23V regulation threshold accuracy, and DFN-8 (3mm × 2mm) thermal performance with θJA = 75°C/W when VSS is soldered.

Technical Context

The LTC4366CDDB-2#TRMPBF implements a floating architecture where regulation circuitry is powered from the MOSFET source (OUT pin), enabling operation with input voltages far exceeding its own absolute maximum ratings. Its overvoltage protection relies on a precision 1.23V feedback reference referenced to OUT, driving an external N-channel MOSFET gate via a charge pump delivering up to 12V above OUT.

It integrates dual shunt regulators (12V on VDD, 5.7V on OUT), a 9µA TIMER pin current source for adjustable overvoltage timing, and a 9-second internal cool-down timer after fault. The -2 variant auto-retries after cool-down, unlike the -1 latch-off version, and supports shutdown with <14µA quiescent current.

Key Specifications

Pinout & Package

Package: 8-lead (3mm × 2mm) plastic DFN with exposed pad (pin 9), RoHS-compliant, lead-free finish. VSS must be soldered to PCB for specified θJA = 75°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC4366CDDB-1#TRMPBF, the LTC4366CDDB-2#TRMPBF eliminates manual reset requirements but trades off deterministic fault isolation. Versus TPS26631RGER, it enables much higher voltage protection and thermal management flexibility at the cost of external component count.

Availability

LTC4366CDDB-2#TRMPBF is available at Aetrix Electronics and suitable for 28V vehicle systems, avionic DC bus protection, and industrial high-voltage DC distribution requiring stable component supply across automotive and aerospace production cycles.

Supply support for LTC4366CDDB-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 (now part of Analog Devices, Inc., a wholly owned subsidiary of Analog Devices, Inc.) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors.

The LTC4366 product line delivers high-voltage surge protection ICs designed specifically for floating, ultra-wide-input DC distribution systems in automotive, avionics, and industrial applications.

FAQ

What is the key functional difference between LTC4366CDDB-2#TRMPBF and LTC4366CDDB-1#TRMPBF?

The LTC4366CDDB-2#TRMPBF features auto-retry behavior: after an overvoltage fault, it enters a 9-second cool-down period and then automatically resumes operation. In contrast, the LTC4366CDDB-1#TRMPBF latches off permanently until the SD pin is actively toggled low then high to clear the fault. This makes the -2 variant ideal for unattended systems like vehicle ECUs where manual intervention is impractical.

How does LTC4366CDDB-2#TRMPBF achieve operation with input voltages exceeding 500V?

The LTC4366CDDB-2#TRMPBF uses a floating architecture: its regulation circuitry is powered from the external MOSFET's source (OUT pin), not ground. Input voltage appears across the MOSFET and external resistors (RSS, RIN), while internal pins (VDD, OUT, BASE) operate within safe voltage ranges via integrated shunt regulators (12V on VDD, 5.7V on OUT). This decouples internal circuitry from input voltage magnitude.

What is the role of the TIMER pin on LTC4366CDDB-2#TRMPBF, and how is it configured?

The TIMER pin on LTC4366CDDB-2#TRMPBF controls overvoltage regulation duration. It charges at 9µA during regulation; when voltage reaches 2.8V, an overvoltage fault is triggered. A capacitor (CT) from TIMER to VSS sets timing: CT = 3.2 nF/ms. For example, a 100nF capacitor yields ~31ms regulation before fault. Leaving TIMER open defaults to 1µs regulation - effectively disabling sustained regulation.

Can LTC4366CDDB-2#TRMPBF be used with P-channel MOSFETs?

No, the LTC4366CDDB-2#TRMPBF is designed exclusively for N-channel MOSFETs. Its GATE driver outputs up to 12V above OUT, which is required to fully enhance high-side N-MOSFETs in floating configurations. Driving a P-channel device would require gate voltage below source - incompatible with the LTC4366CDDB-2#TRMPBF's architecture and pin functions (e.g., BASE is intended for external PNP, not PMOS gate control).

What thermal considerations apply to the DFN package of LTC4366CDDB-2#TRMPBF?

The LTC4366CDDB-2#TRMPBF in the 3mm × 2mm DFN package achieves θJA = 75°C/W only when the exposed pad (pin 9) is soldered to a PCB ground plane. If unsoldered, θJA degrades to 135°C/W. Designers must ensure adequate copper area and thermal vias under the pad to manage power dissipation during sustained overvoltage regulation, especially given the 9-second cool-down timer's thermal duty cycle constraints.