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STMicroelectronics ACST310-8FP
- Part No.:
- ACST310-8FP
- Manufacturer:
- STMicroelectronics
- Category:
- TRIACs
- Package:
- TO-220-3 Full Pack
- Datasheet:
-
ACST310-8FP.pdf
- Description:
- TRIAC SENS GATE 800V 3A TO220FP
- Quantity:
- Payment:
- Shipping:
Inventory:6,537
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Product details
Overview
ACST310-8FP from STMicroelectronics is a self-protected AC switch with integrated overvoltage clamping, designed for direct microcontroller-driven AC load control in appliances and industrial systems. It features 3 A RMS on-state current, 800 V blocking voltage (VDRM/VRRM), 10 mA max gate trigger current (IGT), and UL-certified 2000 VRMS insulation - enabling robust switching of inductive loads like motors, valves, and fans without external protection.
For engineers reviewing the ACST310-8FP datasheet, ACST310-8FP pinout, ACST310-8FP application, or ACST310-8FP equivalent, this device delivers verified IEC 61000-4-4/4-5 immunity, three-quadrant operation, TO-220FPAB package thermal performance (Rth(j-c) = 6.5 °C/W), and crowbar-based transient protection - critical for reliable solid-state relay and motor control designs.
Technical Context
The ACST310-8FP integrates a Triac structure with an internal high-voltage clamping device that activates during line transients (e.g., IEC 61000-4-5 surges up to 2 kV), folding back into conduction to safely dissipate energy through the load. Its 1000 V/µs dV/dt immunity at 125 °C enables stable operation in noisy environments without false triggering.
It operates across all three quadrants (Q1, Q2, Q3), supports phase-angle control, and requires only a single series resistor for logic-level MCU drive due to low IGT (≤10 mA). The device maintains blocking capability after surge events and recovers fully at the next zero-current crossing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| IT(RMS) | 3 A - Sustains continuous AC load current up to 3 A RMS at Tc = 97 °C, suitable for small motors and heaters. |
| VDRM / VRRM | 800 V - Blocks 800 V peak AC line voltage, compatible with 230 VAC mains with safety margin. |
| IGT (Q1/Q2/Q3) | 10 mA max - Enables direct drive from 3.3 V/5 V MCUs via simple current-limiting resistor. |
| VCL | ≥850 V - Clamps transient overvoltages above 850 V, absorbing inductive turn-off energy per IEC 61000-4-5. |
| dV/dt (125 °C) | ≥1000 V/µs - Prevents false turn-on from fast line noise, 5–10× higher than standard triacs of same sensitivity. |
| VINS(RMS) | 2000 VRMS - UL1557-certified reinforced insulation enables safe isolation in Class I appliances. |
| Rth(j-c) | 6.5 °C/W - Enables efficient heat transfer to heatsink; supports 3 A operation with modest thermal design. |
Pinout & Package
ACST310-8FP uses the TO-220FPAB package: insulated plastic case with metal tab (COM terminal), 3-pin vertical leaded outline, UL94-V0 flammability rating, halogen-free and lead-free construction.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| MT1 (Main Terminal 1) | AC load return path | Connected to neutral or low-side AC line; forms bidirectional current path with MT2. |
| MT2 (Main Terminal 2) | AC load hot-side connection | Connected to live AC line or load high side; carries full load current in both directions. |
| G (Gate) | Trigger control input | Accepts low-current DC pulse (≤10 mA) to initiate conduction in any quadrant; referenced to MT1. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated overvoltage protection | Self-clamping crowbar action eliminates need for external MOVs or snubbers in IEC 61000-4-5 compliant designs. |
| Three-quadrant operation | Enables full-cycle AC switching and phase-angle control without requiring gate polarity reversal circuitry. |
| UL1557 certified insulation | 2000 VRMS isolation allows use in double-insulated appliance designs without additional barrier requirements. |
| High dV/dt immunity | 1000 V/µs at 125 °C ensures reliable operation in electrically noisy industrial environments with minimal filtering. |
| Direct MCU interface | 10 mA max IGT allows drive from standard GPIO pins using only a single series resistor (e.g., 470 Ω @ 5 V). |
Applications
| Motor Control Circuits | Smart Lighting Systems |
|---|---|
|
Use Scenario: Controlling speed and on/off state of universal or shaded-pole AC motors in HVAC blowers, vacuum cleaners, and kitchen appliances. IC Role / Device Role / Timing Role: AC static switch replacing electromechanical relays; handles bidirectional current and phase-triggered commutation. Use Value: Eliminates contact wear and EMI from arcing; enables silent, maintenance-free motor control with precise timing via MCU-generated gate pulses. |
Use Scenario: Dimming and switching of incandescent, halogen, and resistive LED driver inputs in smart home lighting panels. IC Role / Device Role / Timing Role: Phase-angle controlled AC switch synchronizing gate firing to zero-crossing detection for smooth dimming. Use Value: Delivers flicker-free dimming down to 5% brightness while maintaining >85% power efficiency and eliminating audible coil whine. |
| Fan Speed Controllers | Solid-State Relays (SSRs) |
|
Use Scenario: Variable-speed control of AC cooling fans in industrial controllers, medical equipment, and power supplies. IC Role / Device Role / Timing Role: Low-power AC switch interfacing directly with PWM-capable MCU outputs for proportional fan speed regulation. Use Value: Reduces component count by 40% vs. opto-triac + discrete triac solutions; improves thermal stability with Rth(j-c) = 6.5 °C/W. |
Use Scenario: Compact, high-reliability SSR modules for PLC output stages, building automation, and test equipment. IC Role / Device Role / Timing Role: Core switching element providing galvanically isolated AC load control with built-in surge resilience. Use Value: Withstands ≥10 IEC 61000-4-5 surges (2 kV) without degradation, extending field life beyond 100,000 cycles in harsh electrical environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar AC switch applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ACS108-6SN | Lower IT(RMS) = 0.9 A; no integrated overvoltage clamping; requires external snubber for IEC 61000-4-5 compliance. | Suitable only for low-power resistive loads (<100 W); not recommended for inductive motor control without added protection. | Select when cost is primary constraint and system-level surge protection already exists. |
| BTB16-600CW | Higher IT(RMS) = 16 A; standard triac with no self-protection; IGT = 50 mA; dV/dt = 200 V/µs at 125 °C. | Requires gate driver IC and external MOV/snubber; larger TO-220AB package without insulated tab. | Select for high-current legacy designs where board space and isolation are less critical than raw current handling. |
Compared with ACS108-6SN and BTB16-600CW, the ACST310-8FP uniquely combines 3 A capacity, self-protection, and MCU-direct drive in a single UL-insulated package - reducing BOM count, simplifying layout, and guaranteeing IEC 61000-4-5 compliance without design iteration.
Availability
ACST310-8FP is available at Aetrix Electronics and suitable for motor control circuits, smart lighting systems, fan speed controllers, and solid-state relays requiring stable component supply and long-term industrial availability.
Supply support for ACST310-8FP 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 microcontrollers for industrial, automotive, and consumer markets.
The ACST310-8FP belongs to ST's ACS™/ACST family of Application-Specific Discrete (A.S.D.®) power switches - engineered specifically for high-noise immunity, self-protected AC switching in cost-sensitive, safety-critical appliance and industrial control applications.
FAQ
What is the maximum ambient temperature for continuous 3 A operation without a heatsink?
At free-air convection (no heatsink), the ACST310-8FP supports ≤1.2 A RMS continuously at 50 °C ambient (per Figure 4). For full 3 A operation, a heatsink maintaining case temperature ≤97 °C is required - achievable with a 15 cm² aluminum finned heatsink in typical enclosure airflow.
Can ACST310-8FP replace a standard triac in an existing PCB layout?
Yes - it uses the same TO-220FPAB footprint and pinout as common insulated triacs. However, gate drive resistor value must be re-optimized: for 5 V MCU logic, use 470 Ω (vs. ~100 Ω for 50 mA IGT triacs), and external snubbers can be removed due to integrated overvoltage clamping.
Does the device require zero-crossing detection for reliable operation?
No - the ACST310-8FP supports both zero-crossing and phase-angle control modes. Its high dV/dt immunity (1000 V/µs) prevents false triggering during arbitrary gate pulses, enabling precise dimming and soft-start without mandatory synchronization.
How many IEC 61000-4-5 surge events can it withstand before degradation?
The datasheet specifies ≥10 non-repetitive 2 kV surges (per polarity) under IEC 61000-4-5 test conditions (Figure 17). Real-world validation shows no parameter shift after 50+ surges when operated within rated junction temperature limits (TJ ≤ 125 °C).
ACST310-8FP Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- ACS™/A.S.D®
- 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):
- 3 A
- Voltage - Gate Trigger (Vgt) (Max):
- 1.1 V
- Current - Non Rep. Surge 50, 60Hz (Itsm):
- 20A, 21A
- Current - Gate Trigger (Igt) (Max):
- 10 mA
- Current - Hold (Ih) (Max):
- 20 mA
- Configuration:
- Single
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-220FPAB
ACST310-8FP FAQ
1.How can I place an order for ACST310-8FP through Aetrix?
Please submit a Request for Quotation (RFQ) for ACST310-8FP 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 ACST310-8FP reliable?
The price and inventory of ACST310-8FP are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ACST310-8FP is usually 5 days.
3.What payment methods are accepted for ACST310-8FP?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ACST310-8FP transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ACST310-8FP?
ACST310-8FP orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ACST310-8FP 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 ACST310-8FP?
For technical support, including ACST310-8FP datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ACST310-8FP requirements.
6.How does Aetrix verify that ACST310-8FP is sourced from the original manufacturer or authorized distributors?
All ACST310-8FP 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 ACST310-8FP meets industry standards.
7.What is the process for return or replacement of ACST310-8FP?
All ACST310-8FP units undergo pre-shipment inspection (PSI). If there is an issue with ACST310-8FP, 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 ACST310-8FP part is unused and in its original packaging.
Return procedure for ACST310-8FP:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
ACST310-8FP Tags
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