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STMicroelectronics ACST2-8SFP

Name: ACST2-8SFP
Brand: STMicroelectronics
SKU: ACST2-8SFP
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: ACST2-8SFP

Manufacturer:: STMicroelectronics

Category:: TRIACs

Package:: TO-220-3 Full Pack

Datasheet:: ACST2-8SFP.pdf

Description:: TRIAC SENS GATE 800V 2A TO220FP

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Product details

Overview

ACST2-8SFP from STMicroelectronics is a 2 A, 800 V RMS overvoltage-protected AC switch (Triac with integrated crowbar clamping), designed for direct microcontroller-driven AC on/off control of inductive loads such as solenoids, fans, pumps, and micro-motors in home appliances and industrial systems. It features IGT ≤ 10 mA gate sensitivity, dV/dt > 500 V/µs at 125 °C, and 1500 V_RMS insulation voltage in TO-220FPAB package.

For engineers reviewing the ACST2-8SFP datasheet, ACST2-8SFP pinout, ACST2-8SFP application, or ACST2-8SFP equivalent, this device is selected for robust line-transient immunity (IEC 61000-4-5), zero-external-snubber inductive switching up to 2 A, and direct logic-level interfacing without buffer stages - critical for space-constrained appliance control boards.

Technical Context

The ACST2-8SFP integrates a planar Triac structure with an on-die overvoltage crowbar clamp that activates at ≥850 V (V_CL) to safely fold back into conduction during transient surges, dissipating energy through the load. Its high static dV/dt immunity (>500 V/µs) and low I_GT (≤10 mA) are achieved via A.S.D.® (Application Specific Discrete) process technology, enabling reliable turn-on under noisy conditions while maintaining off-state blocking integrity.

It operates in quadrants I, II, and III, supports full-sine RMS current up to 2 A at T_c = 105 °C, and withstands non-repetitive surge peaks up to 8.0 A (50 Hz, 20 ms). The TO-220FPAB package provides 1500 V_RMS reinforced insulation and thermal resistance R_th(j–c) = 7 °C/W, enabling direct heatsink mounting without isolation barriers.

Key Specifications

Parameter	Value and Actual Design Meaning
IT(RMS)	2 A - Sustains continuous AC load current up to 2 A at case temperature ≤105 °C without external heatsink derating.
VDRM / VRRM	800 V - Blocks 800 V peak AC line voltage, suitable for 230 V_RMS mains with safety margin.
IGT (max)	10 mA - Enables direct drive from MCU GPIO or low-power logic via single series resistor (e.g., 1.2 kΩ @ 12 V).
dV/dt (min)	500 V/µs @ 125 °C - Resists fast transients per IEC 61000-4-4 without false triggering.
VCL (min)	850 V - Clamps line transients per IEC 61000-4-5 up to 2 kV peak superimposed on mains, preventing destructive breakdown.
VINS(RMS)	1500 V - Reinforced insulation enables safe use in Class I appliances without additional barrier requirements.
Rth(j–c)	7 °C/W - Allows predictable thermal design with standard TO-220 heatsinks; junction-to-case path optimized for power cycling reliability.

Pinout & Package

ACST2-8SFP is housed in the TO-220FPAB package: insulated tab, 3-pin vertical mount, UL94 V0 epoxy, 0.4–0.6 N·m mounting torque, 260 °C soldering tolerance. Tab is electrically isolated and rated for 1500 V_RMS working voltage.

Pin/Terminal	Circuit Role	Design Meaning
G (Gate)	Control input	Low-current trigger terminal (IGT ≤ 10 mA); accepts DC or phase-controlled pulses; referenced to COM.
COM (Common)	Reference node	Return path for gate drive and AC load return; connects to neutral or low-side AC reference point.
OUT (Output)	Main AC output	Switched AC output terminal; carries full load current (up to 2 A RMS); connected to hot/live side of load.

Key Features

Feature	Design Value
Integrated overvoltage crowbar protection	Clamps transients ≥850 V and folds into safe conduction mode - eliminates need for MOVs, snubbers, or external clamps.
High noise immunity with low gate drive	500 V/µs dV/dt @ 125 °C combined with ≤10 mA IGT - achieves sensitive control without sacrificing robustness in EMI-heavy environments.
Direct microcontroller interface	No level-shifting or buffer IC required - gate driven by 3.3 V or 5 V MCU GPIO through single resistor (e.g., 1.2 kΩ).
Planar Triac structure	Ensures stable off-state leakage (<0.5 mA @ 125 °C) and high commutation reliability for inductive turn-off without snubber.

Applications

Washing Machine Motor Control

Dishwasher Solenoid Valve

Use Scenario: On/off sequencing of universal motor during spin/rinse cycles in mains-powered washing machines.

IC Role / Device Role / Timing Role: AC solid-state switch replacing mechanical relay; handles 2 A inductive motor load with zero-crossing compatible timing.

Use Value: Eliminates contact wear, reduces acoustic noise, and withstands repeated 2 kV line surges per IEC 61000-4-5 without degradation.

Use Scenario: Precise 100–500 ms activation of water inlet solenoid valves in dishwasher control modules.

IC Role / Device Role / Timing Role: Low-power AC switch triggered by MCU PWM or GPIO; operates in quadrant I/III with fast turn-on (<1 µs).

Use Value: No external snubber needed for 2 A inductive kickback; gate drive current ≤10 mA simplifies PCB layout and reduces BOM count.

Fan Speed Control in HVAC

Industrial Pump Sequencing

Use Scenario: Stage-based on/off control of AC centrifugal fans in residential HVAC units.

IC Role / Device Role / Timing Role: Mains-switching element in fan power stage; interfaces directly with 3.3 V MCU via 1.5 kΩ gate resistor.

Use Value: 1500 V_RMS insulation meets reinforced isolation requirements; dV/dt immunity prevents false triggering from nearby compressor switching.

Use Scenario: Duty-cycled start/stop control of 120 V/230 V AC submersible pumps in irrigation or factory fluid systems.

IC Role / Device Role / Timing Role: High-reliability AC switch handling repetitive 2 A inductive loads with >10⁵ cycle lifetime.

Use Value: Integrated crowbar absorbs pump turn-off energy spikes; eliminates MOV aging and failure risk in unattended operation.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
ACS108-8SN	Lower IT(RMS) = 0.8 A; same 800 V rating and crowbar protection; DPAK package.	Suitable only for sub-1 A resistive/low-inductance loads; not rated for 2 A motor/pump switching.	Select when board space is constrained and load current ≤0.8 A; requires different thermal layout.
BTB08-600SL	Standard Triac, no integrated crowbar; IGT = 35 mA; VDRM = 600 V; TO-220AB package (non-isolated tab).	Requires external MOV + RC snubber for IEC 61000-4-5 compliance; gate drive needs buffer stage for MCU compatibility.	Select only if cost is primary constraint and design can accommodate added components and isolation measures.

Compared with ACS108-8SN and BTB08-600SL, ACST2-8SFP uniquely delivers 2 A switching, integrated transient protection, and logic-level gate drive in a single insulated package - reducing component count, board area, and qualification effort for IEC-compliant appliance designs.

Availability

ACST2-8SFP is available at Aetrix Electronics and suitable for washing machine motor control, dishwasher solenoid actuation, and HVAC fan switching requiring stable component supply across multi-year production programs.

Supply support for ACST2-8SFP 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 ACST2 series belongs to ST's ACS™/ACST power switch family built with A.S.D.® technology - engineered specifically for robust, snubberless AC load control in cost-sensitive, safety-critical white goods and industrial equipment.

FAQ

Does ACST2-8SFP require a heat sink in typical 2 A appliance applications?

At 2 A RMS and T_c ≤ 105 °C, the TO-220FPAB package's R_th(j–c) = 7 °C/W allows operation with a small finned heatsink (≥15 cm² copper area) in natural convection. Without heatsink, derating to ~1.3 A is required at ambient 50 °C per Figure 4. Thermal performance must be validated per actual PCB copper area and airflow.

Can ACST2-8SFP replace a mechanical relay in a 230 V AC, 1.8 A fan application?

Yes - it supports 2 A RMS at 230 V AC, offers >10⁶ switching cycles (vs. relay's ~10⁵), eliminates contact arcing, and withstands IEC 61000-4-5 2 kV surges without external protection. Gate drive requires only a 1.2 kΩ resistor from a 5 V MCU GPIO; no flyback diode or snubber is needed for fan inductance.

What is the maximum allowable gate resistor value for reliable triggering at 3.3 V MCU logic?

With IGT ≤ 10 mA max and V_GT ≤ 1.1 V, a 220 Ω resistor limits gate current to ~10 mA at 3.3 V, ensuring margin for voltage drop and temperature drift. Values up to 330 Ω remain functional at room temperature but may fail at high junction temperature or low V_CC; 220–270 Ω is the recommended range for 3.3 V systems.

How does the crowbar protection behave during a 2 kV IEC 61000-4-5 surge?

When V_OUT exceeds V_CL (≥850 V), the internal crowbar triggers within nanoseconds, forcing the device into low-impedance conduction for <10 ms. Energy is safely dissipated through the load, and the device recovers full blocking capability after the next zero-current crossing - verified for ≥10 polarity-reversed surges per test standard.

ACST2-8SFP Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

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

Packaging:: Tube

Product Status:: Obsolete

Triac Type:: Logic - Sensitive Gate

Voltage - Off State:: 800 V

Current - On State (It (RMS)) (Max):: 2 A

Voltage - Gate Trigger (Vgt) (Max):: 1.1 V

Current - Non Rep. Surge 50, 60Hz (Itsm):: 8A, 8.4A

Current - Gate Trigger (Igt) (Max):: 10 mA

Current - Hold (Ih) (Max):: 10 mA

Configuration:: Single

Operating Temperature:: -40°C ~ 125°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220FPAB

ACST2-8SFP FAQ

1.How can I place an order for ACST2-8SFP through Aetrix?

Please submit a Request for Quotation (RFQ) for ACST2-8SFP 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 ACST2-8SFP reliable?

The price and inventory of ACST2-8SFP are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ACST2-8SFP is usually 5 days.

3.What payment methods are accepted for ACST2-8SFP?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ACST2-8SFP transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for ACST2-8SFP?

ACST2-8SFP orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your ACST2-8SFP 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 ACST2-8SFP?

For technical support, including ACST2-8SFP datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ACST2-8SFP requirements.

6.How does Aetrix verify that ACST2-8SFP is sourced from the original manufacturer or authorized distributors?

All ACST2-8SFP 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 ACST2-8SFP meets industry standards.

7.What is the process for return or replacement of ACST2-8SFP?

All ACST2-8SFP units undergo pre-shipment inspection (PSI). If there is an issue with ACST2-8SFP, 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 ACST2-8SFP part is unused and in its original packaging.

Return procedure for ACST2-8SFP:

1.Submit a request within 90 days.

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

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