ST's ACS Triacs, or ACST, act as a Triacs, but with an enhanced voltage-transient clamping and absorbing capability.

Both transients generated by load commutation and those coming from the mains line, such as those described in IEC 61000-4-5, are successfully absorbed by the device and the system. The clamping and crowbar function of the ACST ensure safe transient behavior for the system and the ACST. The circuit can thus be simplified, with no need for MOV or snubber circuits.

These devices have 800 V blocking capability, with standard and logic level gate choices.
They are available in Fullpack, IPAK, DPAK, D²PAK or I²PAK packages.

Increase immunity and reduce BOM with new 800 V AC switch

Drive loads subjected to high AC line spikes and transients with ST’s new logic-level ACST310; a 3 A, 800 V overvoltage-protected AC switch. Its high-voltage robustness and surge voltage capabilities prove its reliability in low-power appliance systems, and saves PCB space as any MOV protection or RC network can be removed. Available in two package versions, the ACST310-8B in DPAK and the ACST310-8FP in a 2kV UL1557-certified TO-220FPAB, it allows any standard microcontroller to drive resistive or inductive loads up to 250 W.