ST's ACS Triacs, or ACST, act as a Triac, 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 functions 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.
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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.
eDesignSuite
eDesignSuite is a comprehensive set of easy-to-use design-aid utilities ready to help you streamline the system development process with a wide range of ST products.
Power Management Design Center
Thermal-electrical Simulators for Components
Signal Conditioning Design Tool
NFC/RFID Calculators
Choose design tool: 
SMPS design, by topology, by type and by product PFC design with analog and digitial control Supports various PCB configurations 
Handles AC-DC and DC-DC design in common topologies Displays interactive and annotated schematic Provides current/voltage graphs, Bode plots, efficiency curves and power-loss data 
Provides a step-by-step optimized design of power section and control loop Generates the STM32Cube embedded software package for custom applications and allows firmware project generation, compatible with multiple STM32 IDEs 
Specify input/output power for each node in the tree Check for consistency Design each individual node
Power Supply Design Tool
SMPS design, by topology, by type and by product PFC design with analog and digitial control Supports various PCB configurations Choose type: DC/DC AC/DC Solar Battery Charger
LED Lighting Design Tool
Handles AC-DC and DC-DC design in common topologies Displays interactive and annotated schematic Provides current/voltage graphs, Bode plots, efficiency curves and power-loss data Choose type: DC/DC AC/DC
Digital Power Workbench
Provides a step-by-step optimized design of power section and control loop Generates the STM32Cube embedded software package for custom applications and allows firmware project generation, compatible with multiple STM32 IDEs Choose type: ZVS Totem Pole PFC FB LLC Vienna Rectifier 3-Level T-type Converter
Power Tree Designer
Specify input/output power for each node in the tree Check for consistency Design each individual node Choose design tool: 
Select ratings and application waveforms Get junction temperature and blocking voltage graphs Search and sort suitable devices 
Select ratings and application waveforms Estimate power losses Search and sort suitable devices 
Supports long mission profiles Provides power loss and temperature graphs Helps define heatsink thermal properties 
Help select the right ViPOWER Automotive power device Supports load-compatibility, wiring harness optimization, fault condition impact and diagnostic analysis Supports various PCB configurations 
Specify system ratings and surge waveform Search and sort suitable devices
AC Switches Simulator
Select ratings and application waveforms Get junction temperature and blocking voltage graphs Search and sort suitable devices Rectifier Diodes Simulator
Select ratings and application waveforms Estimate power losses Search and sort suitable devices STPOWER Studio
Supports long mission profiles Provides power loss and temperature graphs Helps define heatsink thermal properties Twister Sim
Help select the right ViPOWER Automotive power device Supports load-compatibility, wiring harness optimization, fault condition impact and diagnostic analysis Supports various PCB configurations TVS Simulator
Specify system ratings and surge waveform Search and sort suitable devices Choose design tool: 
Handles multi-stage-designs and common topologies Returns circuit component values Provides gain, phase and group delay graphs Low Pass, High Pass and Band Pass 
Handles most common configurations Returns circuit components values Provides I/O signal waveforms Inverting, Non Inverting, Window 
Returns circuit component values Provides current error graphs 
Provides current error graphs. Help to select the right High side current sensing and shunt devices.
Active Filters
Handles multi-stage-designs and common topologies Returns circuit component values Provides gain, phase and group delay graphs Low Pass, High Pass and Band Pass Comparators
Handles most common configurations Returns circuit components values Provides I/O signal waveforms Inverting, Non Inverting, Window Low side Current Sensing
Returns circuit component values Provides current error graphs High side Current Sensing
Provides current error graphs. Help to select the right High side current sensing and shunt devices. Choose design tool: 
Input geometry and substrate properties Get antenna impedance 
Enter forward and reverse link characteristics The tool returns link budget estimate 
Enter antenna parameter and matching target Select the topology of the matching network The tool returns component values for the desired design targets
NFC Inductance
Input geometry and substrate properties Get antenna impedance UHF Link Budget
Enter forward and reverse link characteristics The tool returns link budget estimate NFC Tuning Circuit
Enter antenna parameter and matching target Select the topology of the matching network The tool returns component values for the desired design targets