September 5, 2018 — Littelfuse, Inc. introduced six series of sensitive, standard and alternistor TRIAC, designed for use as semiconductor switches in appliances and equipment powered by line AC voltages up to 220V RMS . This combination of packaging, temperature capabilities and choice of current ratings makes them suited for Internet of Things (IoT) applications that require compact design but don’t involve continuous high currents such as smart doorbells, thermostats, ceiling fans/lights, door locks, etc. The sensitive-type components guarantee low current gate control in Quadrants I and IV to interface directly with digital control circuitry. Standard-type components normally operate in Quadrants I and III and are triggered from the AC line.
Alternistor-type components only operate in Quadrants I, II, and III, are triggered from the AC line, and are used in circuits requiring high dv/dt capability. With a maximum junction temperature of 150 °C, these components help circuit designers facing thermal management issues due to limited or no heat sinking by providing a larger thermal design margin. Their surge capabilities enable handling cold in-rush currents in heater or motor control applications. Typical applications for TRIAC include:
- 24VAC control such as smart doorbells, thermostats, sprinkler timers, door locks, etc.
- 110VAC control such as smart ceiling lights/fans, LED flood lights, etc.
- AC solenoid/valve control
- AC heating control and AC motor control
