STMicroelectronics BTA26-800BRG

Overview

BTA26-800BRG from STMicroelectronics is a 25 A, 800 V RMS insulated TRIAC in TOP3 package, designed for AC mains switching in phase-control and on/off applications. It supports standard (4-quadrant) and snubberless (3-quadrant) commutation, features 2500 VRMS insulation rating, 0.9 °C/W junction-to-case thermal resistance, and operates from –40 °C to +125 °C. Used in light dimmers, motor speed controllers, and static relays.

For engineers reviewing the BTA26-800BRG datasheet, BTA26-800BRG pinout, BTA26-800BRG application, or BTA26-800BRG equivalent, key selection criteria include peak surge current (250 A @ 50 Hz), dV/dt immunity (≥500 V/µs), gate trigger current (50 mA max for standard mode), and insulated tab compliance with UL 1557 (file 81734).

Technical Context

This TRIAC implements bidirectional AC conduction controlled by a single gate terminal, enabling full-cycle or phase-angle control of resistive and inductive loads. Its snubberless operation eliminates external RC networks for commutation in 3-quadrant mode, while 4-quadrant capability allows triggering with either polarity of gate signal relative to MT1.

Thermal performance is optimized via clip-bonding construction, delivering low R_th(j-c) (0.9 °C/W) and high I_TSM (250 A at 50 Hz). The insulated TOP3 package provides 2500 VRMS isolation between the MT2 terminal and heatsink mounting surface, meeting safety requirements for industrial and appliance designs.

Key Specifications

Pinout & Package

The BTA26-800BRG uses the TOP3 insulated package with three terminals: MT1 (Main Terminal 1), MT2 (Main Terminal 2), and G (Gate). The insulated tab (MT2) enables direct mounting to a heatsink without electrical isolation hardware.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar TRIAC switching applications.

Compared with BTB26-800BWRG, BTA26-800BRG simplifies heatsink integration via built-in insulation but trades 0.3 °C/W higher thermal resistance; versus BTA26-600BRG, it adds 200 V blocking headroom essential for global 230 VAC compatibility and transient protection.

Availability

BTA26-800BRG is available at Aetrix Electronics and suitable for static relays, heating regulation, and induction motor starting circuits requiring stable component supply and long-term industrial availability.

Supply support for BTA26-800BRG 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, MCU, and sensor solutions for industrial, automotive, and consumer markets.

The BTA/BTB26 series belongs to ST's high-power AC switching portfolio, engineered specifically for robust, thermally efficient TRIAC-based control in mains-powered appliances and industrial equipment.

FAQ

What is the maximum allowable case temperature for continuous 25 A operation?

The BTA26-800BRG sustains 25 A RMS current at Tc = 100 °C, as specified in Absolute Maximum Ratings. Exceeding this temperature requires current derating per Figure 2 in DS13701. At Tc = 110 °C, maximum IT(RMS) drops to approximately 21 A.

Does BTA26-800BRG require a heatsink in all applications?

Yes - continuous 25 A operation mandates a heatsink due to power dissipation (P ≈ IT² × R_D + IT × V_TM). Even at 10 A, thermal simulation shows junction temperature exceeding 125 °C without heatsinking. The insulated tab is designed for direct heatsink attachment, not passive cooling.

Can BTA26-800BRG be used in zero-crossing switched AC applications?

No - it is not optimized for zero-crossing switching. Its design emphasizes high dV/dt immunity and robust commutation for phase-control, not low-noise turn-on at voltage zero. For zero-crossing operation, ST's T-series or dedicated zero-crossing opto-TRIACs (e.g., MOC3063) are recommended.

What is the gate trigger voltage threshold (VGT) and how does it affect drive circuit design?

VGT is guaranteed ≤1.3 V at 25 °C (Table 2). This low threshold allows direct drive from 3.3 V or 5 V microcontrollers with appropriate current limiting (e.g., 100 Ω series resistor for 50 mA IGT). At elevated temperatures, VGT decreases slightly, improving noise immunity but requiring verification of minimum gate drive margin.