STMicroelectronics ACST6-7SFP

Overview

ACST6-7SFP from STMicroelectronics is a 6 A, 800 V RMS overvoltage-protected AC switch (Triac with integrated crowbar clamping), designed for direct mains-connected static switching of inductive AC loads such as universal motors and compressors in home appliances. It features low gate trigger current (<10 mA), 1500 V_rms insulation, and self-protection against IEC 61000-4-5 line surges up to 2 kV.

For engineers reviewing the ACST6-7SFP datasheet, ACST6-7SFP pinout, ACST6-7SFP application, or ACST6-7SFP equivalent, this device serves as a robust, snubberless replacement for standard Triacs in appliance motor control where transient immunity, thermal reliability, and MCU-direct drive capability are critical.

Technical Context

The ACST6-7SFP integrates a planar Triac structure with an on-die high-voltage clamping device enabling automatic crowbar-mode turn-on during overvoltage events - not just voltage limiting. Its dV/dt immunity exceeds 500 V/µs at 125 °C with gate open, and it sustains repetitive 6 A RMS conduction at T_c = 92 °C in TO-220FPAB package.

It operates across all four quadrants (I, II, III) with guaranteed I_GT ≤ 10 mA and V_GT ≤ 1.0 V at 25 °C, and maintains stable latching/holding behavior (I_L ≤ 40 mA, I_H ≤ 25 mA) over –40 °C to +125 °C junction temperature range.

Key Specifications

Pinout & Package

ACST6-7SFP uses the TO-220FPAB insulated package: epoxy-isolated tab, 1500 V_rms insulation, screw-mountable with 0.4–0.6 N·m torque, and thermally optimized for conduction cooling. The plastic body provides UL94 V0 flammability rating.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ACS108-7SN and BTB16-600CW, ACST6-7SFP uniquely delivers 6 A snubberless inductive switching with reinforced insulation and self-protecting clamping - reducing system-level validation time and component count while enabling compact, certified appliance designs.

Availability

ACST6-7SFP is available at Aetrix Electronics and suitable for washing machine motor control, refrigerator compressor drive, induction cooktop thermal management, and industrial AC solenoid actuation requiring stable component supply, long-lifecycle support, and IEC-compliant transient resilience.

Supply support for ACST6-7SFP 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 ACST™ family was developed specifically for robust, snubberless AC load control in white goods and industrial equipment - prioritizing transient immunity, thermal ruggedness, and simplified MCU interface over generic Triac performance.

FAQ

Is ACST6-7SFP pin-compatible with standard TO-220 Triacs like BT136 or TYN612?

No. While ACST6-7SFP shares the same TO-220FPAB outline and 3-pin configuration (G, OUT, COM), its internal crowbar protection and insulated tab require updated PCB layout and thermal mounting. Gate drive remains compatible, but the insulated tab eliminates need for insulating washers used with standard TO-220AB devices.

Can ACST6-7SFP replace a mechanical relay in a 230 V AC, 5 A resistive load application?

Yes - with qualification. It supports 6 A RMS resistive loads at T_c ≤ 92 °C and offers faster switching, silent operation, and longer lifetime than relays. However, verify zero-crossing timing compatibility and ensure gate drive meets I_GT ≤ 10 mA spec; no snubber is needed for resistive loads.

What is the maximum allowable gate resistor value when driving ACST6-7SFP from a 3.3 V MCU GPIO?

For reliable triggering at 25 °C, R_G must limit gate current to ≥10 mA. With 3.3 V drive and V_GT ≤ 1.0 V, R_G ≤ (3.3 − 1.0) V / 0.01 A = 230 Ω. At elevated temperature, derate to ≤180 Ω to maintain margin across –40 °C to +125 °C operation.

Does ACST6-7SFP require a heatsink in a sealed washing machine control module?

Yes - for continuous 6 A operation. At T_c = 92 °C, R_th(j-c) = 4.25 °C/W implies ~25.5 W dissipation (I²R_d ≈ 6² × 0.08 = 2.88 W + switching losses). Even with low conduction loss, ambient >50 °C in sealed enclosures demands a minimum 10 cm² metal chassis area or small finned heatsink to maintain T_j ≤ 125 °C.