STMicroelectronics T1235H-8G-TR

Overview

T1235H-8G-TR from STMicroelectronics is a 12 A, 800 V snubberless triac in D²PAK package, designed for high-noise-immunity AC load switching at up to 150 °C junction temperature. It supports three-quadrant triggering and delivers robust dynamic commutation (dl/dt)_c ≥12 A/ms and static dV/dt ≥2000 V/µs at T_j = 150 °C, enabling reliable control of universal motors, heaters, and inductive loads in compact SMD home appliance designs.

For engineers reviewing the T1235H-8G-TR datasheet, T1235H-8G-TR pinout, T1235H-8G-TR application, or T1235H-8G-TR equivalent, key selection criteria include verified 150 °C thermal rating, D²PAK thermal resistance R_th(j-c) ≤1.1 °C/W, gate trigger current I_GT ≤35 mA, and snubberless operation without external RC networks.

Technical Context

This triac implements ST's high-temperature Snubberless technology, enabling stable conduction and turn-off under harsh thermal and electrical stress. Its three-quadrant triggering (Quadrants I, II, III) reduces gate drive complexity while maintaining immunity to false triggering from fast transients.

Designed for direct mounting on insulated metal substrate (IMS) or FR4 PCBs with ≥2 cm² copper pad, it leverages D²PAK's low R_th(j-c) (≤1.1 °C/W) and UL94-V0 molding compound to sustain 12 A RMS at T_c = 135 °C without forced cooling.

Key Specifications

Pinout & Package

D²PAK (TO-263) package: surface-mount, single-tab outline with 3 leads; thermally optimized for PCB copper pad conduction (SCU = 2 cm² typical); UL94-V0 halogen-free epoxy; ECOPACK2 compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BTB12-800CW and Z0109MN, the T1235H-8G-TR provides superior thermal capability (150 °C T_j, R_th(j-c) ≤1.1 °C/W), verified snubberless operation, and higher noise immunity-making it the only choice for compact, high-reliability SMD designs in demanding home appliance applications.

Availability

T1235H-8G-TR is available at Aetrix Electronics and suitable for home appliance motor control, smart AC plug development, and industrial heater management requiring stable component supply and long-term lifecycle support.

Supply support for T1235H-8G-TR 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, specializing in power, analog, MEMS, and microcontroller technologies for industrial, automotive, and consumer markets.

The T1235H-8G-TR belongs to ST's STPOWER Triac family, engineered specifically for high-temperature, snubberless AC switching in space-constrained, thermally demanding applications such as smart home appliances and industrial controls.

FAQ

What is the maximum recommended case temperature for continuous operation?

The T1235H-8G-TR supports continuous operation at T_c = 135 °C, as validated by its IT(RMS) = 12 A rating under that condition. Exceeding this temperature requires derating per Figure 2 in DS13429; sustained T_c >135 °C risks thermal runaway due to reduced (dl/dt)_c margin and increased leakage current.

Does this triac require a heatsink in a 2-layer FR4 PCB design?

A heatsink is not required if the PCB uses ≥2 cm² of 35 µm copper under the tab (per Figure 7), ambient temperature stays ≤70 °C, and load duty cycle is ≤60%. For 100% duty cycle at 12 A, a low-thermal-resistance heatsink or IMS board is mandatory to maintain T_j ≤150 °C.

Can the T1235H-8G-TR replace a standard 12 A TO-220 triac in an existing design?

No direct drop-in replacement is possible due to different footprint, thermal path, and soldering requirements. The D²PAK package demands re-layout for thermal copper pads and stencil-defined solder paste volume. Electrical behavior is compatible, but thermal validation and gate drive timing must be re-verified for SMD assembly.

Is the gate trigger threshold guaranteed across the full temperature range?

Yes-IGT is specified from -40 °C to +150 °C: min 5 mA and max 35 mA (Table 2). V_GT remains ≤1.3 V across the same range, ensuring compatibility with standard optocoupler drivers even at maximum junction temperature.