Send an Inquiry

To receive a quote for your project, please fill in the following information, and we’ll get back to you promptly.

Submit Inventory List

Please fill in the following information, and we’ll get back to you promptly.

Home > Products > Discrete Semiconductor Products > Thyristors > TRIACs

STMicroelectronics ACST6-7SR

Name: ACST6-7SR
Brand: STMicroelectronics
SKU: ACST6-7SR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: ACST6-7SR

Manufacturer:: STMicroelectronics

Category:: TRIACs

Package:: TO-262-3 Short Leads, I2PAK

Datasheet:: ACST6-7SR.pdf

Description:: TRIAC SENS GATE 700V 6A I2PAK

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:6,617

Please send an inquiry. Send us your inquiry, and we will respond immediately.

Product details

Overview

ACST6-7SR from STMicroelectronics is an overvoltage-protected AC switch (integrated triac + clamping structure) designed for mains-powered static switching in home appliances and industrial controls. It delivers 6 A RMS on-state current, 800 V blocking voltage (V_DRM/V_RRM), and low 10 mA gate trigger current (I_GT), enabling direct MCU drive without external snubbers in compressor or universal motor control.

For engineers reviewing the ACST6-7SR datasheet, ACST6-7SR pinout, ACST6-7SR application, or ACST6-7SR equivalent, this device serves as a self-protected, high-noise-immunity alternative to standard triacs in IEC 61000-4-4/4-5-compliant AC load switching-especially where board space, component count, and transient resilience are critical.

Technical Context

The ACST6-7SR integrates a planar triac with an internal high-voltage crowbar clamping structure that activates at ≥850 V (V_CL) to safely absorb inductive turn-off energy and withstand 2 kV line surges per IEC 61000-4-5. Its dV/dt immunity exceeds 500 V/µs at 125 °C with gate open, and it sustains 100 A/µs critical dI/dt during commutation.

It operates across –40 to +125 °C junction temperature, features 1500 V_RMS insulation (TO-220FPAB package), and achieves 4.25 °C/W junction-to-case thermal resistance-enabling reliable 6 A conduction at T_C = 92 °C without forced cooling.

Key Specifications

Parameter	Value and Actual Design Meaning
I_T(RMS)	6 A - Sustains continuous 6 A AC load current (e.g., fridge compressor) at T_C = 92 °C without heatsink derating.
V_DRM/V_RRM	800 V - Blocks full AC mains peaks (e.g., 230 V_RMS × √2 ≈ 325 V) with 2.5× safety margin for surge transients.
I_GT	10 mA max - Enables direct drive from MCU GPIO via single series resistor (no buffer IC required).
V_CL	≥850 V - Clamps line transients before destructive breakdown, eliminating need for external MOVs or RC snubbers.
dV/dt (gate open)	≥500 V/µs at 125 °C - Prevents false triggering from fast EFT bursts (IEC 61000-4-4) without gate filtering.
R_th(j-c)	4.25 °C/W - Delivers efficient heat transfer to heatsink, supporting compact thermal design in sealed appliance enclosures.
I²t (tp = 10 ms)	13 A²s - Supports fuse coordination for short-circuit protection without nuisance blowing during motor startup inrush.

Pinout & Package

ACST6-7SR uses the TO-220FPAB insulated package (1500 V_RMS isolation, epoxy UL94 V0 rated), with metal tab electrically isolated from all terminals. Mounting torque: 0.4–0.6 N·m.

Pin/Terminal	Circuit Role	Design Meaning
G	Gate	Low-current trigger input (≤10 mA); referenced to COM; enables zero-crossing or phase-angle control via MCU.
OUT	Main output terminal (anode 2)	Carries full load current (6 A RMS); connects to AC load (e.g., motor winding); bidirectional conduction path.
COM	Common reference (anode 1 / MT1)	Return path for load current; tied to neutral or AC line reference; defines voltage reference for gate and clamping circuitry.

Key Features

Feature	Design Value
Integrated overvoltage protection	Self-contained crowbar clamping (V_CL ≥ 850 V) eliminates external MOVs/snubbers and meets IEC 61000-4-5 Level 4.
High noise immunity	500 V/µs dV/dt rating and 100 A/µs dI/dt capability ensure robust operation in EMI-heavy environments (e.g., washing machine control boards).
Direct MCU drivability	10 mA I_GT allows single-resistor interface to 3.3 V/5 V microcontrollers-no level-shifting or driver IC needed.
Thermal reliability	Planar die construction and 4.25 °C/W R_th(j-c) support stable 6 A operation at 92 °C case temperature in confined spaces.
Inductive load compatibility	No external snubber required for 6 A inductive loads (e.g., universal motors, compressors) due to built-in energy absorption.

Applications

Refrigeration Compressor Control

Washing Machine Drum Motor

Use Scenario: On/off cycling of hermetic compressor during thermostat-regulated cooling cycles.

IC Role / Device Role / Timing Role: AC mains switch replacing mechanical relay; handles 6 A inrush and steady-state current with zero-crossing turn-on.

Use Value: Eliminates relay wear-out and contact arcing; integrated clamping prevents surge-induced failure during power-line disturbances.

Use Scenario: Bidirectional speed and direction control of universal motor driving drum rotation.

IC Role / Device Role / Timing Role: Phase-angle controlled AC switch; gate triggered by MCU PWM to regulate motor torque and RPM.

Use Value: Replaces discrete triac + snubber + MOV stack; reduces BOM count by ≥3 components while improving EFT immunity.

Air Conditioner Fan Control

Industrial HVAC Blower

Use Scenario: Static switching of PSC (permanent split capacitor) fan motor in residential AC units.

IC Role / Device Role / Timing Role: Zero-voltage turn-on switch; synchronized to AC zero-crossing for EMI reduction.

Use Value: Achieves silent operation and extends motor life vs. relay; 1500 V_RMS isolation ensures user safety in Class I appliances.

Use Scenario: Duty-cycle modulated control of 3-phase blower motor starter circuits in commercial HVAC systems.

IC Role / Device Role / Timing Role: High-reliability AC load switch handling repetitive 6 A surges during fan ramp-up/down.

Use Value: Withstands 45 A non-repetitive surge (20 ms, 50 Hz) without degradation-critical for frequent start-stop cycles.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
ACST610-8FP	Same die, identical specs, TO-220FPAB package with insulated tab (1500 V_RMS).	Direct drop-in replacement; same footprint and thermal performance; used when reinforced isolation is mandatory.	Select when board-level creepage/clearance requirements exceed 3 mm or safety certification demands reinforced insulation.
ACS108-8SN	Lower 1.2 A RMS rating, no integrated clamping; requires external MOV and snubber for IEC 61000-4-5 compliance.	Suitable only for low-power resistive loads (<1.2 A); not viable for compressor/motor switching without added protection.	Choose only for cost-sensitive, low-current applications where transient protection is handled externally and space permits extra components.

Compared with ACST6-7SR, ACST610-8FP offers identical electrical behavior and enhanced isolation, while ACS108-8SN trades ruggedness and integration for lower cost and smaller size-making ACST6-7SR optimal for medium-power, safety-critical AC switching where reliability and BOM simplification are prioritized.

Availability

ACST6-7SR is available at Aetrix Electronics and suitable for refrigerator compressor control, washing machine drum motor drives, and HVAC blower systems requiring stable component supply, long lifecycle support, and IEC-compliant transient resilience.

Supply support for ACST6-7SR 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 ACST6 series belongs to ST's ACS™/ACST power switch family built with A.S.D.® (application-specific discrete) technology-engineered specifically for robust, snubberless AC mains switching in white goods and industrial controls.

FAQ

What is the maximum ambient temperature for ACST6-7SR in free-air convection?

In free-air convection (no heatsink), ACST6-7SR supports up to 62 °C ambient temperature for 6 A RMS operation when mounted on a 1 cm² copper pad (per D²PAK variant data). For TO-220FPAB, derating begins above 45 °C ambient without forced airflow-consult Figure 4 in Doc ID 7297 Rev 10 for exact IT(RMS) vs. Ta curves.

Does ACST6-7SR require a heatsink for 6 A continuous operation?

Yes-6 A RMS operation requires mounting on a heatsink. At T_C = 92 °C (TO-220FPAB), the device sustains full current; this corresponds to ~40–45 °C heatsink temperature depending on thermal interface and airflow. Without a heatsink, maximum continuous current drops to ~1.5 A (see Figure 3).

Can ACST6-7SR replace a standard triac like BT139-800 in existing designs?

Yes-ACST6-7SR is pin-compatible with BT139-800 in TO-220AB packages (G, OUT, COM mapping matches), but adds integrated overvoltage protection and higher dV/dt immunity. No layout change is needed, though external snubbers/MOVs can be removed to reduce BOM cost and board area.

What is the clamping response time of ACST6-7SR during a 2 kV surge?

Clamping occurs within <100 ns of voltage exceeding V_CL (≥850 V), initiating crowbar action that forces the device into low-impedance conduction. Full current conduction (I_PEAK ≈ 120 A) is achieved within 1 µs, dissipating surge energy through the load-verified per IEC 61000-4-5 test waveform (1.2/50 µs voltage, 8/20 µs current).

ACST6-7SR Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: TO-262-3 Short Leads, I2PAK

Packaging:: Tube

Product Status:: Obsolete

Triac Type:: Logic - Sensitive Gate

Voltage - Off State:: 700 V

Current - On State (It (RMS)) (Max):: 6 A

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

Current - Non Rep. Surge 50, 60Hz (Itsm):: 45A, 50A

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

Current - Hold (Ih) (Max):: 25 mA

Configuration:: Single

Operating Temperature:: -30°C ~ 125°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: I2PAK

ACST6-7SR FAQ

1.How can I place an order for ACST6-7SR through Aetrix?

Please submit a Request for Quotation (RFQ) for ACST6-7SR 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 ACST6-7SR reliable?

The price and inventory of ACST6-7SR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ACST6-7SR is usually 5 days.

3.What payment methods are accepted for ACST6-7SR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ACST6-7SR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for ACST6-7SR?

ACST6-7SR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your ACST6-7SR 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 ACST6-7SR?

For technical support, including ACST6-7SR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ACST6-7SR requirements.

6.How does Aetrix verify that ACST6-7SR is sourced from the original manufacturer or authorized distributors?

All ACST6-7SR 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 ACST6-7SR meets industry standards.

7.What is the process for return or replacement of ACST6-7SR?

All ACST6-7SR units undergo pre-shipment inspection (PSI). If there is an issue with ACST6-7SR, 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 ACST6-7SR part is unused and in its original packaging.

Return procedure for ACST6-7SR:

1.Submit a request within 90 days.

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

Tech Hub

2026-09-08 Obsolete Electronic Components: How to Source and Evaluate Replacements

A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.

2026-09-07 TTL vs CMOS Logic Levels: 74HC and 74HCT Compatibility Explained

TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.

2026-09-04 Logic Level Shifter: How to Connect 3.3V and 5V Logic Safely

A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.

2026-09-03 74HC595 vs TPIC6B595: Output Drive, Pinout, Current, and Load Selection

The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…

2026-09-02 74HC595 Pinout, Timing, Output Current, and Applications

The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…

2026-09-01 Latch vs Flip-Flop: Timing, Differences and Design Choices

A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…

2026-08-30 D Latch Circuit: Truth Table, Timing, ICs and Applications

A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …

2026-08-28 SR Latch Explained: NOR and NAND Circuits, Truth Tables, and Applications

An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…

2026-08-27 Latch Circuit: SR and D Latches, Truth Tables, Timing, and Applications

Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…

2026-08-21 What Is an LED Driver? Types, Circuits, Dimming, and Selection

An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…