STMicroelectronics T1635H-8T

Overview

T1635H-8T from STMicroelectronics is a 16 A, 800 V RMS-rated snubberless triac in TO-220AB package, designed for high-noise-immunity AC load switching at up to 150 °C junction temperature. It supports three-quadrant triggering, delivers 2000 V/µs static dV/dt immunity at Tj = 150 °C, and enables compact thermal design in heater and motor control applications.

For engineers reviewing the T1635H-8T datasheet, T1635H-8T pinout, T1635H-8T application, or T1635H-8T equivalent, key selection criteria include verified commutation robustness (dl/dt)c ≥ 16 A/ms at 150 °C, gate trigger current ≤ 35 mA across all quadrants, and thermal resistance Rth(j-c) ≤ 1.1 °C/W - critical for heatsink-limited industrial and appliance designs.

Technical Context

This triac implements ST's Snubberless high-temperature technology, enabling reliable turn-off under high inductive loads without external snubbers. Its three-quadrant triggering architecture reduces gate drive complexity while maintaining noise immunity via elevated dV/dt thresholds and low IGT dispersion over temperature.

Thermal performance is optimized for conduction at full 16 A RMS with case temperature up to 131 °C, supported by UL94-V0 halogen-free molding and lead-free plating. The device sustains repetitive 800 V blocking and non-repetitive 900 V peak voltage, making it suitable for universal motor control where voltage transients exceed standard line levels.

Key Specifications

Pinout & Package

TO-220AB package: insulated tab, vertical mounting, lead-free plating, UL94-V0 epoxy resin, recommended torque 0.4–0.6 N·m.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BTB16-800CW and TYN616, the T1635H-8T provides superior thermal headroom (150 °C vs. 125 °C), higher dV/dt immunity (2000 vs. 1000 V/µs), and guaranteed commutation robustness - making it the only option qualified for compact, sealed, high-reliability motor and heater control in harsh thermal environments.

Availability

T1635H-8T is available at Aetrix Electronics and suitable for home automation smart plugs, water heater load switching, and universal motor speed control requiring stable component supply across multi-year production cycles.

Supply support for T1635H-8T 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, digital, and mixed-signal ICs for automotive, industrial, and consumer markets.

The T1635H-8T belongs to ST's Snubberless Triac family, engineered specifically for high-temperature, high-noise industrial and appliance control - prioritizing thermal resilience, commutation reliability, and reduced system-level component count.

FAQ

What is the maximum allowable case temperature for continuous 16 A RMS operation?

The T1635H-8T supports continuous 16 A RMS conduction at case temperature (Tc) up to 131 °C, as specified in Absolute Maximum Ratings Table 1. Operation beyond this requires derating per Figure 2 in DS13214, and thermal design must maintain junction temperature ≤ 150 °C using Rth(j-c) ≤ 1.1 °C/W.

Can the T1635H-8T replace a standard 4-quadrant triac in existing designs?

Yes, but gate drive must be adapted: the T1635H-8T operates in Quadrants I, II, and III only - it cannot be triggered in Quadrant IV. Designs relying on Q4 triggering require circuit modification or alternative part selection; otherwise, compatibility is maintained for most phase-control and zero-crossing applications.

Is a heatsink mandatory for 16 A operation in free air?

Yes. With Rth(j-a) = 60 °C/W, free-air operation at 16 A RMS would exceed 150 °C junction temperature even at room ambient. A heatsink with Rth(c-a) ≤ 15 °C/W is required per Figure 6; typical implementation uses a 15–20 cm² aluminum finned heatsink mounted to the insulated TO-220AB tab.

Does the T1635H-8T require a snubber network for inductive loads?

No. Its Snubberless design guarantees (dl/dt)c ≥ 16 A/ms at 150 °C, enabling reliable commutation in universal motor and transformer loads without external RC snubbers. This is validated per test conditions in Table 2 and confirmed in application note AN4375 for ST's high-temperature triac family.