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STMicroelectronics ACS108-8SA-AP

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

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Part No.:: ACS108-8SA-AP

Manufacturer:: STMicroelectronics

Category:: TRIACs

Package:: TO-226-3, TO-92-3 (TO-226AA)

Datasheet:: ACS108-8SA-AP.pdf

Description:: TRIAC SENS GATE 800V 0.45A TO92

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Product details

Overview

ACS108-8SA-AP from STMicroelectronics is a single-pole, 0.8 A RMS, 800 V blocking voltage AC switch with integrated overvoltage crowbar protection (VCL ≥ 850 V), negative-gate-triggered operation (IGT ≤ 10 mA), and TO-92 package. It replaces discrete triac + snubber designs in low-power AC load control for appliances and industrial systems.

For engineers reviewing the ACS108-8SA-AP datasheet, ACS108-8SA-AP pinout, ACS108-8SA-AP application, or ACS108-8SA-AP equivalent, this page delivers verified electrical specs, gate drive requirements, thermal derating curves, clamping behavior under inductive turn-off, and IEC 61000-4-5 surge ruggedness validation - all critical for reliable mains-switching design without external protection components.

Technical Context

The ACS108-8SA-AP uses A.S.D.® (Advanced Static Discharge) technology to implement an overvoltage crowbar structure that clamps transients up to 2 kV (IEC 61000-4-5 compliant) and safely breaks over during high-energy surges. Its gate-level shifter enables direct microcontroller interfacing with only a series resistor (e.g., 220 Ω).

Triggered by negative gate current (flowing *out* of G pin), it operates in Quadrants II and III, supports dV/dt immunity ≥ 2000 V/μs at 125 °C, and maintains stable latching/holding current (IL ≤ 25 mA, IH ≤ 10 mA) across –30 to +125 °C junction temperature.

Key Specifications

Parameter	Value and Actual Design Meaning
IT(RMS)	0.8 A - Maximum continuous AC load current at T_tab = 76 °C with S = 5 cm² heatsink area.
VDRM / VRRM	800 V - Blocking voltage rating for both polarities; ensures safe operation on 230 V_RMS/50 Hz mains with margin.
IGT	≤ 10 mA - Gate trigger current threshold; enables direct drive from MCU GPIO via 220 Ω resistor at 3.3 V or 5 V.
VCL	≥ 850 V - Clamping voltage at I_CL = 0.1 mA; provides headroom before crowbar action during inductive turn-off.
dV/dt	≥ 2000 V/μs - Minimum static dv/dt immunity at 125 °C with gate open; prevents false triggering in noisy environments.
R_th(j-l)	60 °C/W - Junction-to-lead thermal resistance; defines power dissipation limit (P_max ≈ 0.8 W at T_lead = 76 °C).
Package	TO-92 - Through-hole plastic package with common tab (COM) connection; supports shared heatsinking for multi-switch layouts.

Pinout & Package

TO-92 package with three leads: COM (common reference to mains neutral/ground), OUT (switched AC output to load), and G (gate input requiring negative current for turn-on). The metal tab is internally connected to COM, enabling mechanical and thermal mounting to a shared heatsink.

Pin/Terminal	Circuit Role	Design Meaning
COM	Common reference terminal	Internally tied to package tab; connects to AC mains return path (neutral or ground); enables shared cooling pad for multiple switches.
OUT	Switched AC output	Connects to one side of AC load (e.g., solenoid, lamp); voltage referenced to COM; carries full load current during conduction.
G	Negative gate input	Receives sinking current from controller; turn-on triggered when I_G ≥ IGT (≤10 mA); polarity-sensitive - must be driven below COM potential.

Key Features

Feature	Design Value
Overvoltage crowbar protection	VCL ≥ 850 V with energy-dissipating avalanche section - eliminates need for external MOV or RC snubber in inductive load switching.
Direct microcontroller interface	Gate drive requires only one series resistor (e.g., 220 Ω); no level shifter or optocoupler needed due to integrated gate-level shifter.
High noise immunity	dV/dt ≥ 2000 V/μs and burst immunity per IEC 61000-4-4 - ensures robust operation in electrically noisy appliance and industrial environments.
Shared thermal management	COM-connected tab allows multiple ACS devices to mount on same heatsink - reduces PCB space and thermal design complexity.
IEC 61000-4-5 surge compliance	Withstands ±2 kV line-to-line surges (10 shots per polarity) without degradation - validated using standard test circuit with 5 μH/150 Ω load model.

Applications

Appliance Load Switching

Industrial Solenoid Control

Use Scenario: On/off control of washing machine water valves, dishwasher dispensers, or HVAC airflow dampers.

IC Role / Device Role / Timing Role: AC mains switch replacing mechanical relay; commutates 230 V_RMS loads with zero-crossing turn-off recovery.

Use Value: Eliminates relay contact wear and audible click; enables silent, long-life operation with built-in surge protection for home appliance EMI environments.

Use Scenario: Driving 24–120 V AC solenoids in PLC-controlled factory automation systems.

IC Role / Device Role / Timing Role: Solid-state AC switch handling inductive turn-off energy via internal crowbar; triggered by PLC output GPIO.

Use Value: Removes need for external flyback diodes or snubbers; reduces BOM count by >80% versus discrete triac + protection solutions.

Low-Power Motor Control

Lamp Dimming Interface

Use Scenario: Controlling small AC fans or door lock actuators in smart building systems.

IC Role / Device Role / Timing Role: Mains-referenced switching element with gate-level isolation; handles peak currents up to 13.7 A (16.7 ms surge).

Use Value: Enables compact, thermally efficient designs using TO-92 footprint; supports rapid cycling without thermal runaway due to R_th(j-l) = 60 °C/W.

Use Scenario: Phase-cut dimming interface for incandescent or halogen lamps in residential lighting controls.

IC Role / Device Role / Timing Role: AC switch with precise gate timing; supports leading-edge dimming when synchronized to zero-cross detection.

Use Value: Provides clean turn-on with minimal EMI; VCL clamping prevents lamp filament stress during abrupt dimmer cutoff transitions.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
ACS108-6SA-AP	600 V VDRM/VRRM (vs. 800 V); identical IT(RMS) = 0.8 A, IGT ≤ 10 mA, TO-92 package.	Suitable only for 120 V_RMS systems; insufficient blocking margin for 230 V_RMS mains with transients.	Select only for North American 120 V AC applications where lower cost justifies reduced voltage margin.
BT134-600D	Standard 4-quadrant triac; no integrated crowbar; requires external snubber and MOV for IEC 61000-4-5 compliance.	Higher component count, larger PCB area, and unverified surge performance without added protection network.	Use only if legacy triac design reuse is mandatory; not recommended for new designs targeting IEC-compliant reliability.

Compared with ACS108-6SA-AP, the -8SA-AP adds 200 V blocking headroom essential for 230 V mains with surge margin; compared with BT134-600D, it integrates protection that eliminates snubber design effort and improves long-term reliability in inductive switching.

Availability

ACS108-8SA-AP is available at Aetrix Electronics and suitable for appliance control, industrial solenoid actuation, and low-power AC motor switching requiring stable component supply, RoHS-compliant packaging, and consistent TO-92 lead form factor.

Supply support for ACS108-8SA-AP 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 automotive, industrial, and consumer markets.

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

FAQ

What is the correct gate drive configuration for ACS108-8SA-AP?

The ACS108-8SA-AP requires a negative gate current flowing *out* of the G pin - meaning the gate must be pulled below the COM potential. A typical implementation uses a microcontroller GPIO connected through a 220 Ω resistor to G, with COM tied to system ground or neutral. Driving G high relative to COM will not trigger conduction.

Can ACS108-8SA-AP replace a mechanical relay in a 230 V AC, 0.5 A solenoid application?

Yes - it supports 0.8 A RMS continuous current and 800 V blocking voltage, providing ample margin for 230 V AC solenoids. Its integrated crowbar protection absorbs inductive turn-off energy, eliminating the need for external flyback components required with relays or basic triacs.

Does ACS108-8SA-AP require a heatsink in typical operation?

A heatsink is not required for loads ≤ 0.45 A RMS at ambient ≤ 64 °C with 5 cm² copper area (per datasheet Fig. 2). At full 0.8 A RMS, thermal derating mandates T_tab ≤ 76 °C - achievable with a small shared heatsink or PCB copper pour, leveraging the COM-connected tab.

How does the VCL parameter affect circuit design?

VCL ≥ 850 V defines the voltage at which the device enters controlled avalanche clamping. This sets the maximum transient voltage seen by downstream components during inductive turn-off or surge events - allowing designers to select load insulation ratings and PCB creepage/clearance accordingly without adding external clamping devices.

ACS108-8SA-AP Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: ACS™/A.S.D®

Package/Case:: TO-226-3, TO-92-3 (TO-226AA)

Packaging:: Cut Tape (CT)

Product Status:: Active

Triac Type:: Logic - Sensitive Gate

Voltage - Off State:: 800 V

Current - On State (It (RMS)) (Max):: 450 mA

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

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

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

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

Configuration:: Single

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

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92

ACS108-8SA-AP FAQ

1.How can I place an order for ACS108-8SA-AP through Aetrix?

Please submit a Request for Quotation (RFQ) for ACS108-8SA-AP 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 ACS108-8SA-AP reliable?

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

3.What payment methods are accepted for ACS108-8SA-AP?

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

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for ACS108-8SA-AP?

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

Once your ACS108-8SA-AP 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 ACS108-8SA-AP?

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

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

All ACS108-8SA-AP 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 ACS108-8SA-AP meets industry standards.

7.What is the process for return or replacement of ACS108-8SA-AP?

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

Return procedure for ACS108-8SA-AP:

1.Submit a request within 90 days.

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

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