This document describes the application rules of thyristors and bidirectional thyristors, including trigger conditions, conduction states, and temperature effects.
This application note from Philips Semiconductors explains the principles of thyristors (SCRs) and bidirectional triacs, describing their triggering methods, characteristic curves, and temperature effects. It provides ten "golden rules" for reliable design, including gate drive requirements, temperature limits, and protection against dV/dt and dI/dt overstress.
The document also details mechanical mounting techniques such as clip clamping, bolt fixing, and solder‑and‑pin (solder‑and‑pin) methods, and gives thermal‑resistance calculations for various package types (SOT54, SOT78, SOT223, SOT82). Practical circuit solutions like RC snubbers, series inductors, and MOV filters are recommended to improve robustness. This manual is written in Chinese.
| Minimum current rating | 0.8 A |
|---|---|
| Maximum current rating | 25 A |
| Triac package range | 1 A – 25 A (SOT223 to SOT78) |
| Typical thermal resistance (SOT78) | 6 K/W |
| Typical thermal resistance (SOT54) | 100 K/W |
Clip clamping is the recommended method because it provides the smallest thermal resistance.
Add an RC snubber circuit between MT1 and MT2 to limit the voltage rise rate.
A series inductor limits the current rise rate (dI/dt) and protects the triac from damage.
The SOT78 (TO220AB) package supports up to 25 A.