STMicroelectronics T405T-6FP

Overview

T405T-6FP from STMicroelectronics is a 4 A, 600 V logic-level triac in TO-220FPAB package, designed for AC load switching in low-current inductive applications. It features 5 mA gate trigger current, 1.56 V max on-state voltage at 25 °C, and 2000 VRMS insulation rating per UL1557. Used in kitchen appliances, power tools, and induction motor control circuits.

For engineers reviewing the T405T-6FP datasheet, T405T-6FP pinout, T405T-6FP application, or T405T-6FP equivalent, key selection criteria include gate drive compatibility with microcontrollers, thermal resistance (Rth(j-c) = 4.3 °C/W), commutation robustness (dV/dt ≥ 20 V/µs at 125 °C), and UL certification for safety-critical AC mains interfacing.

Technical Context

This triac operates in all three triggering quadrants (I, II, III), enabling full-wave AC phase control without external polarity management. Its logic-level gate (IGT ≤ 5 mA, VGT ≤ 1.3 V) allows direct interface with 3.3 V or 5 V microcontrollers without buffer stages.

Designed for thermally constrained environments, it supports RMS on-state current up to 4 A at case temperature TC = 104 °C and withstands non-repetitive surge currents of 31 A (16.7 ms). The insulated TO-220FPAB package provides 2000 VRMS isolation and enables direct heat sink mounting.

Key Specifications

Pinout & Package

Package: TO-220FPAB - fully insulated, through-hole, heat sink mountable package with UL-rated 2000 VRMS isolation between tab and terminals. Tab is electrically connected to A2 (anode 2).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar logic-level triac applications.

Compared with BTA04-600BWRG and MAC4DCM, T405T-6FP uniquely combines logic-level gate drive, reinforced insulation, and optimized thermal resistance in a through-hole package-making it the preferred choice for safety-certified, thermally demanding, MCU-driven AC load control.

Availability

T405T-6FP is available at Aetrix Electronics and suitable for kitchen appliances, power tools, and induction motor control circuits requiring stable component supply, UL-compliant isolation, and direct microcontroller interface.

Supply support for T405T-6FP 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, delivering intelligent power, analog, MEMS, and microcontroller solutions across automotive, industrial, and consumer markets.

T405T-6FP belongs to ST's logic-level triac product line, engineered specifically for safe, efficient, and microcontroller-compatible AC switching in cost-sensitive, safety-regulated home and portable equipment.

FAQ

Is T405T-6FP compatible with 3.3 V microcontrollers?

Yes. With a maximum gate trigger current of 5 mA and gate trigger voltage of 1.3 V, T405T-6FP can be directly driven by 3.3 V GPIO pins without external amplification. Its three-quadrant operation ensures reliable turn-on regardless of AC polarity, eliminating the need for level-shifting or dual-gate circuitry in phase-control designs.

What is the significance of the "FP" in T405T-6FP?

The "FP" suffix denotes the TO-220FPAB package: a fully insulated, through-hole variant with a metal tab isolated from internal terminals and rated for 2000 VRMS. This differs from standard TO-220AB (non-insulated) and enables safe, direct mounting to grounded heat sinks without additional insulators or thermal pads.

Can T405T-6FP replace a random-phase triac in zero-crossing applications?

No. While T405T-6FP supports zero-crossing switching when gated synchronously, it is not a zero-crossing triac IC. It lacks internal zero-crossing detection circuitry. To implement zero-crossing control, an external zero-crossing detector (e.g., H11AA1) and MCU timing logic must be used to gate the triac precisely at voltage zero crossings.

Does T405T-6FP require a snubber circuit?

A snubber is recommended for inductive loads (e.g., motors, solenoids) to suppress voltage transients during turn-off and prevent false triggering. Although T405T-6FP has high dV/dt immunity (≥20 V/µs), real-world inductive kickback often exceeds this threshold-especially in unfiltered motor drives-so a standard RC snubber (e.g., 100 Ω + 100 nF) is advised per application note AN437.