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STMicroelectronics ACST310-8B
- Part No.:
- ACST310-8B
- Manufacturer:
- STMicroelectronics
- Category:
- TRIACs
- Package:
- TO-252-3, DPAK (2 Leads + Tab), SC-63
- Datasheet:
-
ACST310-8B.pdf
- Description:
- TRIAC SENS GATE 800V 3A DPAK
- Quantity:
- Payment:
- Shipping:
Inventory:3,024
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Product details
Overview
ACST310-8B from STMicroelectronics is a self-protected AC switch built with A.S.D.® technology, integrating a Triac structure with overvoltage clamping for IEC 61000-4-5 compliance. It delivers 3 A RMS on-state current, 800 V blocking voltage (VDRM/VRRM), 10 mA max gate trigger current (IGT), and operates across –40 °C to +125 °C junction temperature - used in motor control, fan speed regulation, and solid-state relays for home appliances and industrial systems.
For engineers reviewing the ACST310-8B datasheet, ACST310-8B pinout, ACST310-8B application, or ACST310-8B equivalent, this page provides verified technical context, DPAK package details, IEC-compliant transient immunity specs, and real-world implementation guidance for inductive/resistive AC load switching.
Technical Context
The ACST310-8B implements an integrated crowbar-based overvoltage protection mechanism that triggers clamping at ≥850 V (VCL) and safely folds back into conduction during transients up to 2 kV peak, recovering after zero-crossing. Its three-quadrant operation (Q1/Q2/Q3) enables phase-angle control without external snubbers.
It achieves high noise immunity via dV/dt ≥1000 V/µs at 125 °C and critical rate of rise of on-state current (dI/dt) ≥50 A/µs - enabling direct microcontroller drive with only a series resistor while maintaining robustness against IEC 61000-4-4 fast transients.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| IT(RMS) | 3 A - Sustains continuous resistive or inductive AC loads up to 3 A RMS without heatsink under Tc = 112 °C. |
| VDRM / VRRM | 800 V - Blocks line voltages up to 800 V peak in both directions, suitable for 230 VRMS mains with safety margin. |
| IGT (Q1–Q3) | 10 mA max - Enables direct logic-level MCU drive using only a current-limiting resistor; no gate driver IC required. |
| VCL | ≥850 V - Clamps inductive turn-off spikes and absorbs IEC 61000-4-5 surge energy, eliminating need for external MOVs or TVS. |
| dV/dt immunity | ≥1000 V/µs at 125 °C - Prevents false triggering from EMI or line noise, outperforming standard triacs by 5–10× at same sensitivity. |
| Rth(j-c) | 3 °C/W - Enables thermal design with case-mounted heatsinking; 3 A load dissipates ~5.4 W (VTM ≈ 1.8 V) at 25 °C. |
Pinout & Package
DPAK (TO-252) package with exposed metal tab (COM terminal) for thermal and electrical connection; UL94-V0 epoxy, lead-free, halogen-free.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| MT1 (Main Terminal 1) | AC load return path | Connected to neutral or low-side of AC load; referenced to COM for gate triggering in Q1/Q2/Q3. |
| MT2 (Main Terminal 2) | AC line input / output | Carries full load current; polarity determines quadrant conduction path relative to gate signal. |
| G (Gate) | Trigger control input | Accepts low-current (≤10 mA) logic pulse to initiate conduction; compatible with 3.3 V/5 V MCUs via series resistor. |
| COM (Tab) | Common reference / thermal path | Internally connected to MT1; must be electrically tied to PCB ground plane or heatsink for thermal management and noise immunity. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated overvoltage clamping | VCL ≥850 V enables IEC 61000-4-5 compliance without external protection components. |
| Three-quadrant operation | Supports phase-angle control in Q1, Q2, and Q3 - eliminates need for gate resistor polarity switching in dimmer/fan control. |
| High dV/dt immunity | 1000 V/µs at 125 °C prevents spurious turn-on in noisy industrial environments with minimal layout filtering. |
| Direct microcontroller interface | 10 mA IGT allows drive from GPIO pins through single resistor - reduces BOM count and board space vs. opto-triac solutions. |
| UL94-V0 & ECOPACK®2 | Flame-retardant resin and RoHS/halogen-free construction meet global safety and environmental compliance requirements. |
Applications
| Motor Control Circuits | Fan Speed Controllers |
|---|---|
Use Scenario: Controlling small AC induction motors in washing machines, HVAC blowers, or pumps. IC Role / Device Role / Timing Role: AC static switch performing zero-crossing or phase-angle turn-on to regulate torque/speed. Use Value: Eliminates mechanical relay wear and arcing; integrated clamping handles motor back-EMF spikes without snubber networks. |
Use Scenario: Variable-speed control of shaded-pole or PSC fans in air purifiers, range hoods, or server cooling. IC Role / Device Role / Timing Role: Phase-controlled AC switch modulating RMS voltage delivered to fan windings. Use Value: Achieves smooth speed adjustment with <10 mA gate drive and withstands commutation transients up to 2 kV per IEC 61000-4-5. |
| Solid-State Relays | Home Appliance Load Switching |
Use Scenario: Replacing electromechanical relays in PLC output modules or industrial I/O cards. IC Role / Device Role / Timing Role: High-reliability AC switching element with fail-safe overvoltage foldback. Use Value: Delivers >10⁶ operations lifetime, supports repetitive 2 kV surge testing, and maintains off-state leakage <500 µA at 125 °C. |
Use Scenario: On/off control of heating elements, solenoid valves, or incandescent lamps in coffee makers, dishwashers, or vacuum cleaners. IC Role / Device Role / Timing Role: Low-power AC switch activated by MCU GPIO with no isolation barrier needed. Use Value: Reduces system cost by removing optocoupler and driver stage; UL94-V0 package meets appliance fire-safety standards. |
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) = 0.8 A; VDRM = 600 V; no integrated overvoltage clamping (requires external MOV). | Suitable only for sub-1 A resistive loads; not rated for IEC 61000-4-5 line surges. | Select when cost is primary constraint and load current ≤0.8 A with external protection available. |
| BTB16-600SL | Standard 16 A triac; IGT = 50 mA; no built-in clamping; requires gate driver and snubber network. | Needs optocoupler + driver + RC snubber for noise immunity and inductive load handling. | Choose only when higher current rating is mandatory and board space/component count are secondary concerns. |
Compared with ACS108-6SN and BTB16-600SL, the ACST310-8B uniquely combines 3 A rating, 10 mA gate sensitivity, and self-contained IEC 61000-4-5 surge protection - reducing total solution size, bill-of-materials, and validation effort for mid-power AC control.
Availability
ACST310-8B is available at Aetrix Electronics and suitable for motor control circuits, fan speed controllers, solid-state relays, and home appliance load switching requiring stable component supply and long-term production support.
Supply support for ACST310-8B 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, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.
The ACST310-8B belongs to ST's ACS™/ACST family of Application-Specific Discrete (A.S.D.®) power switches - engineered specifically for reliable, low-component-count AC load control in cost-sensitive, safety-critical appliances and industrial equipment.
FAQ
What is the maximum AC load current the ACST310-8B can switch continuously?
The ACST310-8B supports 3 A RMS on-state current at case temperature Tc = 112 °C with adequate heatsinking. At ambient temperature with free-air convection and no heatsink, derating applies: maximum continuous current drops to ~1.2 A at 50 °C ambient per Figure 4. Thermal design must account for VTM ≈ 1.8 V and Rth(j-c) = 3 °C/W.
Does the ACST310-8B require a heat sink in typical appliance applications?
A heatsink is recommended for sustained 3 A loads or operation above 60 °C ambient, but many appliance applications (e.g., 1 A fan control, intermittent valve actuation) operate reliably with the DPAK tab soldered directly to a ≥2 cm² copper pour. Thermal performance depends on PCB copper area, airflow, and duty cycle - refer to Figures 3 and 4 for derating curves.
Can the ACST310-8B replace a standard triac like the BT136 in existing designs?
Yes, with circuit modifications: the ACST310-8B uses the same DPAK footprint and three-terminal configuration, but its COM tab is internally tied to MT1 (unlike isolated triacs), requiring grounding of the tab. Gate drive remains compatible (≤10 mA), but external snubbers and MOVs become unnecessary due to integrated clamping and high dV/dt immunity.
How does the overvoltage protection behave during an IEC 61000-4-5 surge event?
Under a 2 kV surge (per Figure 18), the ACST310-8B clamps voltage at ≥850 V and transitions into low-impedance conduction for <10 ms, diverting surge energy through the load. After current crosses zero, it fully recovers blocking capability. This non-repetitive action is validated for ≥10 cycles per polarity without degradation.
ACST310-8B Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- ACS™/A.S.D®
- Package/Case:
- TO-252-3, DPAK (2 Leads + Tab), SC-63
- Packaging:
- Bulk
- Product Status:
- Active
- 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:
- Surface Mount
- Supplier Device Package:
- DPAK
ACST310-8B FAQ
1.How can I place an order for ACST310-8B through Aetrix?
Please submit a Request for Quotation (RFQ) for ACST310-8B 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 ACST310-8B reliable?
The price and inventory of ACST310-8B are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ACST310-8B is usually 5 days.
3.What payment methods are accepted for ACST310-8B?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ACST310-8B transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ACST310-8B?
ACST310-8B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ACST310-8B 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 ACST310-8B?
For technical support, including ACST310-8B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ACST310-8B requirements.
6.How does Aetrix verify that ACST310-8B is sourced from the original manufacturer or authorized distributors?
All ACST310-8B 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 ACST310-8B meets industry standards.
7.What is the process for return or replacement of ACST310-8B?
All ACST310-8B units undergo pre-shipment inspection (PSI). If there is an issue with ACST310-8B, 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 ACST310-8B part is unused and in its original packaging.
Return procedure for ACST310-8B:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
ACST310-8B Tags
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