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Home > Products > Discrete Semiconductor Products > Thyristors > TRIACs

STMicroelectronics ACS108-8TN-TR

Name: ACS108-8TN-TR
Brand: STMicroelectronics
SKU: ACS108-8TN-TR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: ACS108-8TN-TR

Manufacturer:: STMicroelectronics

Category:: TRIACs

Package:: TO-261-4, TO-261AA

Datasheet:: ACS108-8TN-TR.pdf

Description:: TRIAC SENS GATE 800V 0.8A SOT223

Quantity:: RFQ Add To RFQ list

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Inventory:2,627

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Product details

Overview

ACS108-8TN from STMicroelectronics is an overvoltage-protected AC static switch (ACSTM) built with A.S.D.® technology, designed for direct mains-connected load control in appliances and industrial systems. It delivers 0.8 A RMS on-state current, 800 V repetitive peak off-state voltage (VDRM/VRRM), 5 mA gate trigger current (IGT), and integrated overvoltage crowbar clamping at ≥850 V (VCL). It drives inductive loads like solenoids, valves, and low-power motors without external snubbers or varistors.

For engineers reviewing the ACS108-8TN datasheet, ACS108-8TN pinout, ACS108-8TN application, or ACS108-8TN equivalent, key selection criteria include its self-protected turn-off capability for high-inductance loads, negative-gate-triggering interface with microcontrollers, IEC 61000-4-5 surge compliance up to 2 kV, and SOT-223 thermal performance with Rth(j-t) ≤ 25 °C/W.

Technical Context

The ACS108-8TN operates as a single-pole, bidirectional AC switch with gate-level shifter driver isolating digital controllers from mains-referenced switching. Its overvoltage crowbar structure enables safe energy dissipation during inductive turn-off by clamping voltage to ≥850 V while limiting dI/dt to ≥0.8 A/ms under worst-case conditions.

Triggered by negative gate current (IGT ≤ 5 mA), it supports quadrant II–III operation and features high noise immunity: static dV/dt ≥ 600 V/µs at 125 °C and burst immunity per IEC 61000-4-4. The device maintains blocking capability after non-repetitive 2 kV surges (IEC 61000-4-5) and recovers at next zero-crossing.

Key Specifications

Parameter	Value and Actual Design Meaning
IT(RMS)	0.8 A - Maximum continuous load current without heatsink derating at T_tab = 104 °C
VDRM / VRRM	800 V - Peak repetitive blocking voltage across mains terminals (COM–OUT)
IGT	5 mA max - Gate trigger current required for reliable turn-on, enabling direct MCU drive via series resistor
VCL	≥850 V - Clamping voltage during inductive turn-off, eliminating need for external snubber
dV/dt immunity	600 V/µs - Immunity to false triggering from fast line transients at 125 °C junction temperature
Rth(j-t)	≤25 °C/W - Junction-to-tab thermal resistance enabling direct PCB copper pad heat sinking
I²t	1.1 A²s - Fusing energy rating defining short-circuit withstand time before failure

Pinout & Package

SOT-223 package with exposed tab thermally connected to COM terminal; compact footprint (6.5 × 3.5 mm) suitable for high-density industrial PCB layouts.

Pin/Terminal	Circuit Role	Design Meaning
COM	Common reference terminal	Connected to AC mains neutral or phase return path; electrically tied to metal tab for thermal conduction
OUT	Switched output terminal	Connected to load; carries full RMS load current and blocks 800 V peak reverse voltage
G	Negative gate input	Receives sinking current (≤5 mA) from MCU GPIO; triggers conduction when current flows out of G pin

Key Features

Feature	Design Value
Integrated overvoltage crowbar	Clamps turn-off transients ≥850 V, removing need for external MOV or RC snubber
Direct microcontroller interface	Accepts negative gate current (IGT ≤ 5 mA) without level-shifting circuitry
High dV/dt immunity	600 V/µs at 125 °C ensures robust operation in noisy industrial environments
IEC 61000-4-5 surge compliance	Withstands 2 kV line-to-line surges (10× per polarity) without degradation
A.S.D.® technology	Enables precise control of commutation timing and energy dissipation during inductive turn-off

Applications

Appliance Motor Control

Industrial Solenoid Actuation

Use Scenario: Controlling small AC fans and pumps in washing machines and HVAC units.

IC Role / Device Role / Timing Role: AC static switch providing zero-crossing–free, phase-angle–independent on/off control of inductive loads.

Use Value: Eliminates snubber losses and reduces BOM count by integrating overvoltage protection for 15 H inductance loads.

Use Scenario: Driving 24 VAC solenoid valves in programmable logic controller (PLC) output modules.

IC Role / Device Role / Timing Role: Mains-referenced solid-state relay replacement with fast, controlled turn-off.

Use Value: Prevents contact arcing and extends valve lifetime by clamping turn-off voltage to ≤850 V.

Smart Home Load Switching

Commercial Door Lock Control

Use Scenario: Remote-controlled lighting and auxiliary power switching in smart home hubs.

IC Role / Device Role / Timing Role: Isolated AC switch interfacing directly with low-voltage MCU GPIO pins.

Use Value: Enables compact, RoHS-compliant designs meeting IEC 61000-4-4/5 without external protection components.

Use Scenario: Powering electromagnetic door locks in access control panels operating from 115/230 VAC mains.

IC Role / Device Role / Timing Role: Fail-safe AC switch with guaranteed turn-off under high inductance and surge stress.

Use Value: Ensures reliable lock release during power interruption by maintaining clamped voltage during rapid current decay.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
ACS108-6TN	Same package and architecture but rated for 600 V VDRM instead of 800 V	Limited to 120 VAC or low-surge 230 VAC environments; lower clamping margin (VCL ≈ 650 V)	Select only where mains voltage and surge exposure are strictly limited and thermal design allows higher derating
ACS108-8SN	Identical electrical specs but in SO-8 package (Rth(j-a) ≈ 90 °C/W vs. 25 °C/W for SOT-223)	Requires larger PCB area and external heatsinking for same RMS current; no integrated tab thermal path	Choose only if board layout prohibits SOT-223 or requires surface-mount compatibility with legacy SO-8 footprints

Compared with ACS108-6TN and ACS108-8SN, the ACS108-8TN uniquely combines 800 V blocking, ≥850 V clamping, and SOT-223's low Rth(j-t) ≤ 25 °C/W-making it optimal for space-constrained, high-surge industrial AC load switching where thermal efficiency and transient ruggedness are co-critical.

Availability

ACS108-8TN is available at Aetrix Electronics and suitable for appliance motor control, industrial solenoid actuation, and smart home load switching requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for ACS108-8TN 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 markets since 1987.

The ACS AC switch product line targets solid-state replacement of electromechanical relays in AC mains-powered equipment, emphasizing integrated surge protection, simplified drive, and thermal efficiency in compact packages.

FAQ

What is the recommended gate resistor value for driving ACS108-8TN from a 3.3 V MCU GPIO?

For reliable triggering with margin, use a 220 Ω resistor between MCU GPIO and G pin. This limits gate current to ~15 mA peak (well above the 5 mA max IGT requirement) while keeping average gate power below 0.1 W. Ensure the MCU can sink ≥20 mA continuously during turn-on.

Can ACS108-8TN replace a mechanical relay in a 230 VAC, 0.5 A solenoid application?

Yes-ACS108-8TN is qualified for this use case. Its 800 V VDRM exceeds 230 VAC peak (325 V), and its ≥850 V VCL clamps inductive kickback safely. No snubber is needed, and its 0.8 A IT(RMS) rating provides headroom for solenoid inrush currents up to 13.7 A (non-repetitive).

Does ACS108-8TN require a heatsink for 0.8 A RMS operation?

No external heatsink is required if the SOT-223 tab is soldered to ≥5 cm² of 2 oz copper on the PCB. At T_tab = 104 °C, the device sustains 0.8 A RMS continuously. For ambient >60 °C or smaller copper areas, thermal simulation using Rth(j-t) ≤ 25 °C/W is advised.

How does ACS108-8TN handle IEC 61000-4-5 surge testing?

It passes 10× per polarity of 2 kV line-to-line surge (1.2/50 µs + 8/20 µs combination wave) per Figure 18 test setup. During surge, the device breaks over into clamping mode, dissipating energy internally, then recovers blocking capability at the next current zero-crossing-no latch-up or permanent damage occurs.

ACS108-8TN-TR Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: ACS™/A.S.D®

Package/Case:: TO-261-4, TO-261AA

Packaging:: Tape & Reel (TR)

Product Status:: Active

Triac Type:: Logic - Sensitive Gate

Voltage - Off State:: 800 V

Current - On State (It (RMS)) (Max):: 800 mA

Voltage - Gate Trigger (Vgt) (Max):: 1 V

Current - Non Rep. Surge 50, 60Hz (Itsm):: 13A, 13.7A

Current - Gate Trigger (Igt) (Max):: 5 mA

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

Configuration:: Single

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-223

ACS108-8TN-TR FAQ

1.How can I place an order for ACS108-8TN-TR through Aetrix?

Please submit a Request for Quotation (RFQ) for ACS108-8TN-TR 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 ACS108-8TN-TR reliable?

The price and inventory of ACS108-8TN-TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ACS108-8TN-TR is usually 5 days.

3.What payment methods are accepted for ACS108-8TN-TR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ACS108-8TN-TR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for ACS108-8TN-TR?

ACS108-8TN-TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your ACS108-8TN-TR 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 ACS108-8TN-TR?

For technical support, including ACS108-8TN-TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ACS108-8TN-TR requirements.

6.How does Aetrix verify that ACS108-8TN-TR is sourced from the original manufacturer or authorized distributors?

All ACS108-8TN-TR 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 ACS108-8TN-TR meets industry standards.

7.What is the process for return or replacement of ACS108-8TN-TR?

All ACS108-8TN-TR units undergo pre-shipment inspection (PSI). If there is an issue with ACS108-8TN-TR, 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 ACS108-8TN-TR part is unused and in its original packaging.

Return procedure for ACS108-8TN-TR:

1.Submit a request within 90 days.

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

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