ACS108-5SA

Overview

The STMicroelectronics ACS108-5SA is a bidirectional triac (AC switch) in the ASD™ family, designed for AC line switching applications. It features a repetitive peak off-state voltage (VDRM/VRRM) of 500 V and an RMS on-state current (IT(RMS)) of 0.8 A at Tlead = 75 °C. The device incorporates an integrated overvoltage crowbar structure with a clamping voltage (VCL) of 600 V to absorb inductive turn-off energy. Gate triggering requires a negative current sourced from the gate pin, with a maximum gate trigger current (IGT) of 10 mA and a maximum gate trigger voltage (VGT) of 1 V. It operates within a junction temperature range of -30 °C to +125 °C and is housed in a TO-92 package.

Feature Summary

• Integrated overvoltage protection using crowbar technology to meet IEC 61000-4-5 surge standards without external components.
• High noise immunity against static dV/dt and burst requirements.
• Direct interface capability with microcontrollers via a dedicated gate level shifter driver.
• Common package tab connection supports parallel mounting on shared cooling pads.

Applications

• Static switching in household appliances such as washing machines, dishwashers, and refrigerators.
• Control of low-power high-inductive or resistive loads including solenoids, valves, relays, and dispensers.
• Drive systems for pumps, fans, micro-motors, and defrost heaters.

Procurement Notes

Verify component authenticity by checking markings against official datasheet specifications. Confirm package type matches the required form factor. Ensure compliance with RoHS directives if applicable to the target market. Review the manufacturer's discontinuation notices prior to finalizing procurement plans.

Selection Notes

Select this component for circuits requiring direct microcontroller interfacing without additional isolation. Verify that the load current does not exceed the rated IT(RMS) under expected thermal conditions. Ensure the application environment remains within the specified operating temperature limits. Consider the TO-92 package constraints for thermal management in dense layouts.

Part Context

The ACS108-5SA belongs to the ACS108 series of AC switches built around the ASD™ concept. This family integrates high-voltage clamping structures and gate drivers to simplify AC line control designs. The device eliminates the need for external snubbers or varistors, reducing overall component count and simplifying printed circuit board layout.

Replacement Considerations

The ACS108-5SN serves as a functional alternative offering identical electrical characteristics in a SOT-223 package. Designers must account for mechanical differences when substituting between TO-92 and SOT-223 form factors.