STMicroelectronics ACST830-8T

Overview

ACST830-8T from STMicroelectronics is an 8 A, 800 V overvoltage-protected AC switch (Triac-based ASD device) designed for direct control of inductive AC loads without external snubbers. It features integrated overvoltage clamping (V_CL ≥ 850 V), static dV/dt immunity > 2000 V/µs at 125 °C, and TO-220AB insulated package with 2000 V_RMS insulation rating - enabling IEC 61000-4-5 compliance in washing machine motor drives and refrigerator compressors.

For engineers reviewing the ACST830-8T datasheet, ACST830-8T pinout, ACST830-8T application, or ACST830-8T equivalent, this device serves as a self-protected, high-noise-immunity AC mains switching solution for medium-power home appliance motor control where snubberless operation, thermal robustness up to 125 °C junction temperature, and line transient ruggedness are critical selection criteria.

Technical Context

The ACST830-8T implements an application-specific discrete (ASD) Triac structure with monolithically integrated overvoltage crowbar protection. Its clamping action triggers safe conduction during transients (e.g., IEC 61000-4-5 2 kV surges), limiting voltage across the load to ≤ V_CL while dissipating energy through the load path for <10 ms.

It operates in all four quadrants with gate trigger current ≤30 mA and exhibits planar-junction reliability, achieving dI/dt capability ≥100 A/µs and (dI/dt)_c ≥8 A/ms without snubber. Thermal resistance R_th(j-c) is 2 °C/W in TO-220AB, supporting 8 A RMS conduction at T_c = 105 °C.

Key Specifications

Pinout & Package

ACST830-8T uses the TO-220AB package: insulated plastic case with three leads (G, COM, OUT), UL-certified (E81734), 260 °C soldering tolerance, and mechanical dimensions per DS2106 Table 5 (e.g., D = 15.25–15.75 mm, E = 10.00–10.40 mm).

Key Features

Applications

Equivalent & Alternatives

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

Compared with ACST830-8FP and ACST830-8GTR, the ACST830-8T offers lowest-cost through-hole assembly with proven thermal interface to bolt-on heatsinks - ideal for cost-sensitive, medium-volume appliance production where TO-220AB mechanical robustness and serviceability are prioritized.

Availability

ACST830-8T is available at Aetrix Electronics and suitable for washing machine motor control, refrigerator compressor switching, and HVAC blower drive applications requiring stable component supply, long-lifecycle support, and consistent parametric performance across production batches.

Supply support for ACST830-8T 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, specializing in power management, analog, MEMS, and microcontroller technologies for industrial, automotive, and consumer markets.

The ACST8 series belongs to ST's Application-Specific Discrete (ASD) power switch family, engineered specifically for snubberless, high-reliability AC mains control in home appliances - addressing thermal stress, line transients, and long-term reliability challenges in motor-driven systems.

FAQ

What is the maximum continuous load current the ACST830-8T can switch in a washing machine motor application?

The ACST830-8T supports 8 A RMS continuous conduction at case temperature T_c = 105 °C in TO-220AB package, validated for universal drum motors with typical 5–7 A RMS operating current and 80 A inrush surges. Derating is required above 105 °C case temperature per Figure 2 in DS2106.

Does the ACST830-8T require an external snubber network when driving a compressor motor?

No. The device integrates overvoltage clamping (V_CL ≥ 850 V) and achieves (dI/dt)_c ≥ 8 A/ms without snubber, enabling direct connection to inductive loads like fridge compressors. This eliminates external RC networks while maintaining IEC 61000-4-5 surge immunity up to 2 kV.

How does the ACST830-8T protect against line transients per IEC 61000-4-5?

During a 2 kV surge (1.2/50 µs voltage, 8/20 µs current), the ACST830-8T enters controlled on-state foldback below V_CL, diverting surge energy through the load for <10 ms. It recovers full blocking capability after the next zero-crossing, with no latch-up or parameter shift - verified for ≥10 polarity-switched tests.

Can the ACST830-8T be used with standard microcontroller GPIO pins for gate triggering?

Yes. With I_GT ≤ 30 mA and V_GT ≤ 1.0 V, the gate can be driven directly by most 3.3 V or 5 V MCU GPIOs using a series resistor (e.g., 150 Ω for 3.3 V). For enhanced noise immunity in industrial settings, optocoupler isolation (e.g., MOC3021) is recommended but not mandatory.