STMicroelectronics T405-600T

Overview

T405-600T from STMicroelectronics is a 4 A, 600 V three-quadrant logic-level triac in TO-220AB package, designed for AC phase-control switching of inductive loads. It features 5 mA maximum gate trigger current (IGT), 1.56 V max on-state voltage (VTM) at 5.5 A, and 50 A/µs critical dI/dt rating - enabling reliable commutation in universal motor and electrovalve circuits without snubber networks.

For engineers reviewing the T405-600T datasheet, T405-600T pinout, T405-600T application, or T405-600T equivalent, this device is selected for low-power AC load control where gate drive simplicity, high commutation robustness, and thermal stability up to 125 °C junction temperature are required.

Technical Context

The T405-600T uses ST's Snubberless logic-level triac architecture, supporting triggering in all three quadrants (I, II, III) with symmetrical gate sensitivity. Its 5 mA IGT max enables direct drive from microcontrollers or optocouplers without amplification.

It delivers 30 A non-repetitive surge current (50 Hz, 20 ms), 2.6 °C/W junction-to-case thermal resistance, and 20 V/µs minimum dV/dt immunity at 125 °C - ensuring stable turn-off under fast-rising AC transients in motor and appliance applications.

Key Specifications

Pinout & Package

TO-220AB package: insulated or non-insulated variant; tab is MT2 (Main Terminal 2); requires mechanical torque of 0.4–0.6 N·m for mounting.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar triac-based AC switching applications.

Compared with BT136-600D, T405-600T offers superior commutation and snubberless operation; versus T410-600T, it enables lower-power gate drivers while maintaining identical thermal and voltage specs - making it optimal for space-constrained, low-noise appliance PCBs.

Availability

T405-600T is available at Aetrix Electronics and suitable for universal motor control, electrovalve actuation, and kitchen appliance heating requiring stable component supply across industrial production cycles.

Supply support for T405-600T 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, designing and manufacturing analog, power, and microcontroller solutions for industrial, automotive, and consumer markets.

The T4 series triacs are part of ST's power discrete portfolio, engineered specifically for snubberless AC phase-control in cost-sensitive, thermally constrained appliances and motor-driven equipment.

FAQ

Is T405-600T compatible with zero-crossing optocouplers like MOC3041?

No - T405-600T is a logic-level triac optimized for phase-angle control, not zero-crossing switching. MOC3041 triggers only at voltage zero-crossing and lacks the gate timing precision needed for dimming or soft-start. Use MOC3021 or MOC3052 for phase-controlled gate drive instead.

What is the maximum ambient temperature for continuous 4 A operation in TO-220AB package?

At 4 A IT(rms), the T405-600T reaches thermal equilibrium at 110 °C case temperature. With Rth(j-a) = 60 °C/W for TO-220AB on FR4, maximum safe ambient is ~75 °C - assuming no forced airflow and minimal copper area. Derate linearly above that.

Does T405-600T require a heat sink in a 230 VAC, 300 W fan motor application?

Yes - at 300 W (≈1.3 A RMS), power dissipation is ~2 W. While TO-220AB alone achieves ~75 °C/W, a small 5 cm² aluminum heatsink (Rth ≈ 25 °C/W) keeps junction temperature below 100 °C. Mounting torque must be 0.4–0.6 N·m to ensure thermal contact.

Can T405-600T replace BT137-600E in an existing design?

Only with validation - BT137-600E has 10 mA IGT and different dI/dt (25 A/µs). T405-600T's 5 mA IGT may cause marginal triggering if gate drive impedance exceeds 1.2 kΩ, and its higher dI/dt could expose layout parasitics. Recalculate gate resistor and verify commutation margin.