STMicroelectronics ACS108-5SA-TR

Overview

ACS108-5SA-TR from STMicroelectronics is an AC line switch (solid-state relay replacement) designed for full-cycle ON/OFF control of low-power inductive/resistive loads in appliance systems. It features 500 V blocking voltage (VDRM/VRRM), 0.8 A RMS on-state current (IT(RMS)), 600 V clamping voltage (VCL), gate trigger current <10 mA, and integrated gate driver with COM-referenced SOT-223 tab - used in washing machine door locks, solenoid valves, and micro-motor controls.

For engineers reviewing the ACS108-5SA-TR datasheet, ACS108-5SA-TR pinout, ACS108-5SA-TR application, or ACS108-5SA-TR equivalent, this page delivers verified electrical specs, thermal resistance values, IEC61000-4-5 surge compliance details, gate drive interface requirements, and validated alternatives for appliance-grade AC switching design.

Technical Context

The ACS108-5SA-TR implements ST's ASD™ architecture: a monolithic high-voltage silicon switch integrating avalanche clamping (VCL = 600 V) to absorb inductive turn-off energy and a level-shifted gate driver that isolates the microcontroller from mains-referenced switching. It operates with negative gate current sourced from the controller.

Triggering requires a resistor-limited negative current flowing out of the G pin, referenced to COM; no external snubber or overvoltage protection is needed. The TO-92 package provides 150 °C/W junction-to-ambient thermal resistance at Tlead = 75 °C, supporting 0.3 A RMS in ambient-limited conditions.

Key Specifications

Pinout & Package

ACS108-5SA-TR uses a TO-92 plastic package (3-pin, through-hole) with lead material compliant to RoHS. The tab is non-thermal and electrically isolated; thermal path relies on lead conduction (Rth(j-l) = 60 °C/W). Pin 1 = G (Gate), Pin 2 = COM (Common reference), Pin 3 = OUT (Switch output).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar AC line switching applications.

Compared with ACS108-5SN, the -5SA-TR offers simpler through-hole assembly but lower thermal headroom; versus BT134-600D, it eliminates snubber design effort and guarantees 2 kV surge survival - critical for modern appliance certification.

Availability

ACS108-5SA-TR is available at Aetrix Electronics and suitable for washing machine control modules, dishwasher actuator drivers, refrigerator defrost systems, and other white-goods applications requiring stable component supply and long lifecycle support.

Supply support for ACS108-5SA-TR includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, power, MCU, and sensor solutions for industrial, automotive, and consumer markets.

The ACS™ AC Switch family was developed specifically for solid-state replacement of electromechanical relays in home appliances - emphasizing surge robustness, gate simplicity, and thermal reliability in cost-sensitive, high-volume environments.

FAQ

What is the maximum ambient temperature for continuous 0.3 A operation?

At 0.3 A RMS, the ACS108-5SA-TR operates within safe limits up to 60 °C ambient temperature when mounted per standard TO-92 footprint on FR4 PCB with 35 µm copper. Derating begins above this point due to Rth(j-a) = 150 °C/W; junction temperature must remain ≤125 °C.

Can the ACS108-5SA-TR drive a 230 V AC relay coil rated at 0.25 A?

Yes - the device supports 0.25 A inductive loads without turn-off aid circuits, as confirmed in Table 1 for "relay" grouping (dI/dt)c ≥ 0.15 A/ms and turn-off delay <20 ms. Its 600 V clamping voltage safely absorbs coil flyback energy, eliminating need for external diodes or RC snubbers.

Is a series gate resistor required, and how is its value calculated?

Yes - a series resistor limits gate current to <10 mA. For a 5 V MCU GPIO, use R = (5 V − VGT)/IGT ≈ (5 − 1 V)/10 mA = 400 Ω (standard 390 Ω). Resistor power rating must exceed I²R × duty cycle; 0.125 W suffices for intermittent switching.

Does the COM pin carry load current, and what is its voltage rating?

No - COM is the gate drive reference and load return node, not a current-carrying power rail. It connects to AC neutral and must be routed with same creepage/clearance as other mains-referenced traces. Voltage rating matches VDRM: 500 V peak between COM and OUT under blocking conditions.