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Home > Products > Discrete Semiconductor Products > Thyristors > TRIACs

STMicroelectronics T835T-8I

Name: T835T-8I
Brand: STMicroelectronics
SKU: T835T-8I
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: T835T-8I

Manufacturer:: STMicroelectronics

Category:: TRIACs

Package:: TO-220-3

Datasheet:: T835T-8I.pdf

Description:: TRIAC ALTERNISTOR 800V 8A TO220

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Inventory:1,133

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Product details

Overview

T835T-8I from STMicroelectronics is a snubberless 8 A, 800 V RMS triac in a TO-220AB insulated package, designed for AC line switching and phase-angle control in high-commutation environments. It delivers 900 V non-repetitive surge capability (V_DSM/V_RSM), 2.8 °C/W junction-to-case thermal resistance, and operates up to 150 °C junction temperature - enabling reliable motor control and heating applications without external snubber circuits.

For engineers reviewing the T835T-8I datasheet, T835T-8I pinout, T835T-8I application, or T835T-8I equivalent, key selection criteria include its three-quadrant gate triggering (IGT ≤ 35 mA), high static dV/dt immunity (≥1000 V/µs at 150 °C), ceramic-insulated tab rated for 2.5 kV RMS per UL1557, and ECOPACK®2 compliance for RoHS/halogen-free production.

Technical Context

The T835T-8I is a three-quadrant, snubberless triac optimized for robust commutation in AC mains environments. Its design integrates built-in ceramic insulation between the metal tab and die, achieving UL1557 certification (E81734) and 2.5 kV RMS isolation - eliminating need for external insulating washers in mounting.

It supports full-sine-wave RMS current of 8 A at T_c = 118 °C, with critical commutation parameters including (dI/dt)_c ≥ 4 A/ms at 150 °C and dV/dt ≥ 1000 V/µs under hot conditions - directly enabling stable operation in inductive loads like universal motors and solenoid drivers without false triggering.

Key Specifications

Parameter	Value and Actual Design Meaning
IT(RMS)	8 A RMS - supports continuous AC load switching up to 1.8 kW at 230 VAC with case temperature ≤118 °C
VDRM/VRRM	800 V - blocks full AC mains peaks (e.g., 230 VAC × √2 ≈ 325 V) with 2.5× safety margin
VDSM/VRSM	900 V - withstands transient surges (e.g., lightning-induced spikes) without latch-up or failure
IGT	≤35 mA - low gate drive requirement compatible with microcontroller GPIO or optotriac outputs
(dI/dt)c	≥4 A/ms at 150 °C - ensures reliable turn-off in high-temperature inductive loads (e.g., compressor motors)
Rth(j-c)	2.8 °C/W - enables efficient heat transfer to heatsink; allows 8 A operation with <10 °C rise above heatsink
dV/dt	≥1000 V/µs at 150 °C - prevents false triggering from fast-rising noise on AC lines in EMI-prone environments

Pinout & Package

TO-220AB insulated package with electrically isolated metal tab (UL1557 certified, 2.5 kV RMS isolation). Tab serves as Anode 2 (A2) terminal and provides mechanical mounting surface with integrated ceramic insulation layer.

Pin/Terminal	Circuit Role	Design Meaning
A2 (Tab)	Anode 2 / Heat Sink Interface	Electrically isolated metal tab functions as A2 and transfers heat; no external insulator required due to built-in ceramic
A1	Anode 1	Main current path terminal opposite A2; forms bidirectional conduction path with A2 when triggered via G
G	Gate	Three-quadrant trigger input; accepts positive/negative pulses relative to A1; IGT ≤ 35 mA ensures compatibility with low-power drivers

Key Features

Feature	Design Value
Snubberless operation	Validated for phase-control without RC snubber when dV/dt > 20 V/µs and (dI/dt)c limits respected - reduces BOM count and board space
Ceramic-insulated tab	UL1557-certified 2.5 kV RMS isolation eliminates need for mica washers or silicone pads - simplifies thermal/mechanical design
150 °C max Tj	Extends thermal margin beyond standard 125 °C triacs - enables higher power density in compact enclosures with limited airflow
Three-quadrant triggering	Supports gate triggering in Quadrants I, II, and III only - improves noise immunity vs. four-quadrant devices in noisy AC environments
ECOPACK®2 compliance	Lead-free plating + halogen-free molding compound meeting UL94 V0 - satisfies global environmental regulations for consumer and industrial products

Applications

Motor Control

Heating Control

Use Scenario: Speed regulation of universal motors in vacuum cleaners and power tools using phase-angle dimming.

IC Role / Device Role / Timing Role: Bidirectional AC switch controlling conduction angle per half-cycle to adjust average power delivered to motor winding.

Use Value: High (dI/dt)_c (≥4 A/ms at 150 °C) ensures clean turn-off during zero-crossing transitions, preventing torque ripple and audible noise.

Use Scenario: On/off cycling of resistive heating elements in coffee makers and induction cooktop preheaters.

IC Role / Device Role / Timing Role: Zero-voltage-switched (ZVS) AC line switch enabling precise duty-cycle control without inrush current stress.

Use Value: 900 V V_DSM/V_RSM rating absorbs voltage transients from heater coil de-energization, extending system lifetime.

Inrush Current Limiting

Overvoltage Crowbar Protection

Use Scenario: Soft-start circuit for transformer-based power supplies to limit peak inrush into primary winding.

IC Role / Device Role / Timing Role: Gradually increasing conduction angle over first few AC cycles to ramp up current linearly.

Use Value: 63 A non-repetitive surge rating (tp = 16.7 ms) handles cold filament or capacitor charging surges without degradation.

Use Scenario: Fail-safe crowbar across DC bus in SMPS to short-circuit output during overvoltage fault.

IC Role / Device Role / Timing Role: Triggered by comparator output to conduct full AC cycle and blow fuse or trip breaker.

Use Value: 2.5 kV RMS isolation between tab and die prevents fault propagation to control logic ground during catastrophic overvoltage events.

Equivalent & Alternatives

The following parts are listed as comparable options for similar triac switching applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
BTA08-600BWRG	600 V V_DRM, no built-in tab insulation, requires external isolator	Limited to lower-voltage 120 VAC systems; unsuitable for 230 VAC with direct heatsink mounting	Select when cost sensitivity outweighs isolation requirements and board layout accommodates insulating hardware
MAC8Q-8G	8 A/800 V but four-quadrant gate; lower dV/dt (800 V/µs at 125 °C); no UL1557 certification	Higher false-trigger risk in noisy industrial settings; not approved for safety-critical isolated mounting	Prefer where multi-quadrant triggering is needed for legacy driver compatibility, but verify EMI margins

Compared with BTA08-600BWRG and MAC8Q-8G, the T835T-8I uniquely combines UL1557-certified isolation, 900 V surge rating, and 150 °C operation - making it the only option qualified for compact, high-reliability 230 VAC heating/motor controls without external insulation or derating.

Availability

T835T-8I is available at Aetrix Electronics and suitable for motor control circuits, heating systems, and inrush current limiting applications requiring stable component supply and long-term industrial availability.

Supply support for T835T-8I 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, analog, MCU, and sensor technologies for industrial, automotive, and consumer markets.

The T835T-8I belongs to ST's Snubberless™ Triac product line, engineered specifically for high-reliability AC switching in space-constrained, thermally demanding applications - prioritizing commutation robustness, safety certification, and simplified thermal design.

FAQ

Can the T835T-8I be used without a snubber circuit?

Yes - the T835T-8I is explicitly designed for snubberless operation when used within specified limits: dV/dt > 20 V/µs, (dI/dt)_c ≤ rated value, and blocking voltage ≤ V_DRM. Its high dynamic commutation capability (≥4 A/ms at 150 °C) and 1000 V/µs dV/dt immunity eliminate need for external RC networks in most general-purpose AC switching applications.

What is the maximum allowable case temperature for continuous 8 A operation?

The T835T-8I supports 8 A RMS continuous current only when case temperature (T_c) is maintained at ≤118 °C, as defined in Table 2. This corresponds to ~10 °C temperature rise above heatsink for typical mounting with thermal paste, assuming R_th(j-c) = 2.8 °C/W and P_loss ≈ 1.6 W at 8 A.

Is the metal tab electrically isolated from the die?

Yes - the TO-220AB insulated package incorporates a ceramic layer between the silicon die and metal tab, providing 2.5 kV RMS isolation certified to UL1557 (E81734). The tab functions as A2 and may be directly mounted to a grounded heatsink without additional insulation hardware.

Does the T835T-8I support four-quadrant triggering?

No - the T835T-8I is a three-quadrant triac, supporting gate triggering only in Quadrants I (A2+, G+), II (A2–, G+), and III (A2–, G–). It excludes Quadrant IV (A2+, G–), which improves noise immunity in AC line environments where positive gate noise is common.

T835T-8I Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: Snubberless™

Package/Case:: TO-220-3

Packaging:: Tube

Product Status:: Active

Triac Type:: Alternistor - Snubberless

Voltage - Off State:: 800 V

Current - On State (It (RMS)) (Max):: 8 A

Voltage - Gate Trigger (Vgt) (Max):: 1.3 V

Current - Non Rep. Surge 50, 60Hz (Itsm):: 60A, 63A

Current - Gate Trigger (Igt) (Max):: 35 mA

Current - Hold (Ih) (Max):: 40 mA

Configuration:: Single

Operating Temperature:: -40°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220AB Insulated

T835T-8I FAQ

1.How can I place an order for T835T-8I through Aetrix?

Please submit a Request for Quotation (RFQ) for T835T-8I 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 T835T-8I reliable?

The price and inventory of T835T-8I are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for T835T-8I is usually 5 days.

3.What payment methods are accepted for T835T-8I?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for T835T-8I transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for T835T-8I?

T835T-8I orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your T835T-8I 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 T835T-8I?

For technical support, including T835T-8I datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your T835T-8I requirements.

6.How does Aetrix verify that T835T-8I is sourced from the original manufacturer or authorized distributors?

All T835T-8I 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 T835T-8I meets industry standards.

7.What is the process for return or replacement of T835T-8I?

All T835T-8I units undergo pre-shipment inspection (PSI). If there is an issue with T835T-8I, 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 T835T-8I part is unused and in its original packaging.

Return procedure for T835T-8I:

1.Submit a request within 90 days.

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

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