Vishay announced a line of phototriacs that feature a trigger of 1.6 mA and a static dV/dt greater than 5 kV/µs. Encased in a 6-pin DIP package, the zero-crossing (ZC) and non-zero-crossing (NZC) phototriac optocouplers are designed for switching AC loads and driving larger SCRs or TRIACs in industrial applications.  The ZC VO4157 and VO4158 series phototriacs consist of a GaAs infrared LED that is optically coupled to a photosensitive ZC TRIAC detector chip. Devices in the VO4257 and VO4258 series of NZC phototriacs, on the other hand, have the advantage of being able to trigger any time during the ac phase cycle and turn off at the next zero crossing.

Both families have a trigger currents of 1.6 mA, making it possible to directly interface with microcontrollers and digital circuits. Trigger currents of 2.0 mA and 3.0 mA are also available. All three versions are offered in 700-V and 800-V blocking voltages and can provide isolation for low-voltage logic for 120-V, 240-V, and 380-V AC lines to control resistive, inductive, or capacitive loads.

Samples of the VO4157/8 and VO4257/8 phototriacs are available now. Production quantities have a lead-time of six to eight weeks.