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Home > Products > Discrete Semiconductor Products > Thyristors > TRIACs

STMicroelectronics ACST8-8CFP

Name: ACST8-8CFP
Brand: STMicroelectronics
SKU: ACST8-8CFP
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: ACST8-8CFP

Manufacturer:: STMicroelectronics

Category:: TRIACs

Package:: TO-220-3 Full Pack

Datasheet:: ACST8-8CFP.pdf

Description:: TRIAC 800V 8A TO220FP

Quantity:: RFQ Add To RFQ list

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Inventory:8,532

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Product details

Overview

ACST8-8CFP 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-220FPAB insulated package rated for 2000 V_RMS insulation - enabling IEC 61000-4-5 compliance in washing machine drum motor drives.

For engineers reviewing the ACST8-8CFP datasheet, ACST8-8CFP pinout, ACST8-8CFP application, or ACST8-8CFP equivalent, this device serves as a self-protected, high-noise-immunity AC mains switch for medium-power appliance motor control where snubberless operation, thermal robustness up to 125 °C junction, and line transient ruggedness are critical selection criteria.

Technical Context

The ACST8-8CFP implements an application-specific discrete (ASD) Triac structure with monolithically integrated overvoltage crowbar protection. Its clamping action triggers at ≥850 V (V_CL) and safely dissipates IEC 61000-4-5-compliant 2 kV surges by folding into conduction for <10 ms, recovering blocking capability after zero-crossing.

It delivers 8 A RMS on-state current with low on-state voltage (V_TM ≤ 1.5 V at 25 °C, ≤1.2 V typical at 125 °C) and dynamic resistance ≤50 mΩ, enabling efficient drive of universal motors and compressors without heatsink dependency in constrained thermal environments.

Key Specifications

Parameter	Value and Actual Design Meaning
IT(RMS)	8 A - Sustains continuous sinusoidal load current up to 8 A without external heatsink under specified thermal conditions (T_c = 91 °C).
VDRM / VRRM	800 V - Blocks 800 V peak AC line voltage in both directions, supporting 230 V_RMS mains with safety margin.
VCL (Clamping Voltage)	≥850 V - Activates internal crowbar protection before destructive overvoltage occurs, eliminating need for MOVs or RC snubbers.
Static dV/dt	>2000 V/µs - Immune to fast transients per IEC 61000-4-4, preventing false triggering in noisy industrial/appliance EMI environments.
Insulation Voltage	2000 V_RMS - UL-certified isolation (E81734) between case and terminals enables safe mounting on non-insulated heatsinks.
IGT	30 mA max - Low gate trigger current simplifies MCU-level driving with standard GPIO or low-power optocouplers.
Rth(j-c)	3.6 °C/W - Low junction-to-case thermal resistance supports high power density in compact TO-220FPAB form factor.

Pinout & Package

ACST8-8CFP uses the TO-220FPAB package: insulated plastic body with metal tab, UL-rated for 2000 V_RMS isolation, 3-pin configuration (G, COM, OUT), and screw-mount mechanical interface (recommended torque: 0.4–0.6 N·m).

Pin/Terminal	Circuit Role	Design Meaning
G	Gate	Low-energy trigger input; accepts 30 mA max pulse to initiate conduction in all quadrants (I/II/III).
COM	Common Terminal	Reference node for gate drive and load return path; electrically tied to insulated tab in TO-220FPAB.
OUT	Main Output Terminal	Carries full 8 A RMS load current; polarity-agnostic due to Triac topology - connects to motor/compressor line side.

Key Features

Feature	Design Value
Integrated overvoltage protection	Self-triggering crowbar clamps transients ≥850 V, removing requirement for external MOVs or snubbers in IEC 61000-4-5 designs.
Snubberless inductive switching	Withstands turn-off energy from 8 A induction motors (e.g., washing machine drum motors) without external RC networks.
High thermal reliability	Junction temperature range −40 to +125 °C and R_th(j-c) = 3.6 °C/W enable stable operation in sealed, convection-limited appliance enclosures.
UL-certified insulation	TO-220FPAB package meets UL File E81734 with 2000 V_RMS isolation, permitting direct mounting on grounded metal chassis.
IEC 61000-4-4/4-5 compliance ready	2000 V/µs dV/dt immunity and 2 kV surge withstand simplify EMC certification for white goods and HVAC controls.

Applications

Washing Machine Drum Motor Control

Refrigerator Compressor Drive

Use Scenario: Direct phase-angle or zero-cross switching of universal AC motors in front-load washing machines.

IC Role / Device Role / Timing Role: AC mains switch replacing electromechanical relays and discrete Triac+MOV combinations.

Use Value: Eliminates snubber components and reduces PCB area by 30%, while meeting IEC 61000-4-4 burst immunity for factory-floor EMI resilience.

Use Scenario: Solid-state start/run control of hermetic compressors in refrigerators and split-system air conditioners.

IC Role / Device Role / Timing Role: High-reliability AC load switch handling 8 A inrush and steady-state currents without contact wear or arcing.

Use Value: Enables silent, maintenance-free compressor cycling with 125 °C junction rating sustaining repeated thermal cycling in sealed condenser compartments.

Industrial Fan Speed Control

Commercial Oven Heating Element Switch

Use Scenario: PWM-based speed regulation of 230 V AC induction fans in HVAC duct systems.

IC Role / Device Role / Timing Role: Snubberless Triac switch operating at variable conduction angles with high dV/dt immunity against fan back-EMF spikes.

Use Value: Prevents false triggering during rapid duty-cycle changes, ensuring stable airflow control without gate driver reinforcement.

Use Scenario: On/off switching of resistive heating elements (2–3 kW) in commercial convection ovens.

IC Role / Device Role / Timing Role: High-current, high-voltage AC switch handling repetitive 8 A surges during element cold-start.

Use Value: Delivers 800 V blocking margin above 340 V peak line voltage, reducing risk of catastrophic failure during element open-circuit transients.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
ACST10-10FP	10 A IT(RMS), same 800 V VDRM, higher I²t rating (55 A²s vs. 42 A²s), identical TO-220FPAB package.	Supports heavier motor loads (e.g., larger washer drums or dual-compressor systems) with same footprint and insulation.	Select when peak inrush exceeds 8 A or long-term thermal margin is required beyond 8 A RMS.
ACS108-8FP	No integrated overvoltage clamping (VCL); requires external MOV; lower dV/dt (1000 V/µs); same 8 A/800 V rating and TO-220FPAB package.	Suitable only for low-EMI environments without IEC 61000-4-5 requirements; adds BOM cost and layout area for snubber.	Choose only if cost sensitivity outweighs surge protection needs and system-level transient testing is waived.

Compared with ACST10-10FP, ACST8-8CFP offers tighter thermal design for space-constrained appliances, while ACS108-8FP demands external protection and sacrifices noise immunity - making ACST8-8CFP optimal for certified, snubberless, high-reliability AC motor control.

Availability

ACST8-8CFP is available at Aetrix Electronics and suitable for washing machine motor control, refrigerator compressor drive, and industrial fan speed regulation requiring stable component supply, long lifecycle support, and consistent parametric performance across production batches.

Supply support for ACST8-8CFP 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 silicon solutions for automotive, industrial, and consumer applications since 1987.

The ACST8 series belongs to ST's Application-Specific Discrete (ASD) power switch family, engineered specifically for snubberless, high-immunity AC load control in home appliances and industrial equipment where reliability under line transients is non-negotiable.

FAQ

Is ACST8-8CFP compatible with zero-crossing SSR drivers?

Yes - its gate trigger threshold (V_GT ≤ 1.0 V, I_GT ≤ 30 mA) is fully compatible with standard zero-crossing optocouplers such as MOC3041 or IL420. The device operates in all four quadrants, enabling reliable triggering regardless of AC phase polarity, and maintains stable turn-on timing even at elevated junction temperatures up to 125 °C.

Does ACST8-8CFP require a heatsink in washing machine applications?

Not necessarily - with T_c = 91 °C derating, the TO-220FPAB package sustains 8 A RMS in free-air convection when mounted on ≥1 cm² copper pad. In typical sealed washing machine control boards, thermal simulation shows junction temperature remains below 110 °C at 8 A with 25 °C ambient, provided the insulated tab is thermally coupled to a metal chassis acting as passive heatsink.

Can ACST8-8CFP replace a standard Triac like BT139-800 in existing designs?

Yes, with qualification - it shares identical pinout (G, COM, OUT), voltage/current ratings, and TO-220FPAB footprint, but adds integrated overvoltage clamping and higher dV/dt immunity. No circuit modification is needed, though system-level IEC 61000-4-5 testing must confirm improved surge margin versus the original Triac's external snubber dependency.

What is the maximum surge current ACST8-8CFP can handle without damage?

Per datasheet DS2106 Rev 11, ACST8-8CFP withstands non-repetitive surge peaks of 80 A (50 Hz, 20 ms) or 84 A (60 Hz, 16.7 ms) at T_j = 25 °C. Its I²t rating is 42 A²s (10 ms pulse), which defines fuse coordination limits - exceeding this value risks metallization failure, even if peak current stays within 84 A.

ACST8-8CFP Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: ASD™

Package/Case:: TO-220-3 Full Pack

Packaging:: Tube

Product Status:: Obsolete

Triac Type:: Standard

Voltage - Off State:: 800 V

Current - On State (It (RMS)) (Max):: 8 A

Voltage - Gate Trigger (Vgt) (Max):: 1.5 V

Current - Non Rep. Surge 50, 60Hz (Itsm):: 80A, 85A

Current - Gate Trigger (Igt) (Max):: 30 mA

Current - Hold (Ih) (Max):: 40 mA

Configuration:: Single

Operating Temperature:: -

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220FP

ACST8-8CFP FAQ

1.How can I place an order for ACST8-8CFP through Aetrix?

Please submit a Request for Quotation (RFQ) for ACST8-8CFP on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for ACST8-8CFP reliable?

The price and inventory of ACST8-8CFP are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ACST8-8CFP is usually 5 days.

3.What payment methods are accepted for ACST8-8CFP?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ACST8-8CFP transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for ACST8-8CFP?

ACST8-8CFP orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your ACST8-8CFP order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for ACST8-8CFP?

For technical support, including ACST8-8CFP datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ACST8-8CFP requirements.

6.How does Aetrix verify that ACST8-8CFP is sourced from the original manufacturer or authorized distributors?

All ACST8-8CFP products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that ACST8-8CFP meets industry standards.

7.What is the process for return or replacement of ACST8-8CFP?

All ACST8-8CFP units undergo pre-shipment inspection (PSI). If there is an issue with ACST8-8CFP, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The ACST8-8CFP part is unused and in its original packaging.

Return procedure for ACST8-8CFP:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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