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Home > Products > Discrete Semiconductor Products > Thyristors > TRIACs

STMicroelectronics T1235H-8T

Name: T1235H-8T
Brand: STMicroelectronics
SKU: T1235H-8T
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: T1235H-8T

Manufacturer:: STMicroelectronics

Category:: TRIACs

Package:: TO-220-3

Datasheet:: T1235H-8T.pdf

Description:: TRIAC ALTERNISTOR 800V 12A TO220

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Product details

Overview

T1235H-8T from STMicroelectronics is a 12 A, 800 V snubberless triac in TO-220AB package, designed for high-noise immunity AC line switching at up to 150 °C junction temperature. It supports three-quadrant triggering and delivers robust dynamic commutation (dl/dt)_c ≥ 12 A/ms and static dV/dt ≥ 2000 V/µs at T_j = 150 °C, enabling reliable control of universal motors, heaters, and inductive loads in home appliances.

For engineers reviewing the T1235H-8T datasheet, T1235H-8T pinout, T1235H-8T application, or T1235H-8T equivalent, key selection criteria include verified 150 °C thermal rating, gate trigger current (I_GT) ≤ 35 mA across all quadrants, snubberless operation, and TO-220AB mechanical compatibility with standard heatsink mounting.

Technical Context

This triac implements ST's Snubberless high-temperature technology, enabling stable conduction without external snubbers under high dv/dt and high di/dt transients. Its design targets industrial and consumer AC load control where thermal stress and electromagnetic noise challenge conventional triacs.

It operates across all four quadrants but is optimized for I, II, and III quadrant triggering-supporting phase-angle and zero-crossing control topologies. The 1.1 °C/W junction-to-case thermal resistance and UL94-V0 molding resin support compact, thermally efficient PCB-level integration in space-constrained enclosures.

Key Specifications

Parameter	Value and Actual Design Meaning
IT(RMS)	12 A RMS on-state current at T_c = 135 °C - enables continuous drive of heavy AC loads without forced cooling
VDRM/VRRM	800 V repetitive peak off-state voltage - supports mains operation up to 230 VAC with ≥2× safety margin
I_GT	≤35 mA max gate trigger current (Quadrants I–III) - ensures compatibility with low-power microcontroller GPIOs
(dl/dt)_c	≥12 A/ms critical turn-off commutation at T_j = 150 °C - eliminates need for snubber networks with inductive loads
dV/dt	≥2000 V/µs static noise immunity at T_j = 150 °C - prevents false triggering in EMI-rich environments
R_th(j-c)	1.1 °C/W junction-to-case thermal resistance - allows direct heatsink mounting for thermal management down to 135 °C case temp
V_TM	≤1.50 V on-state voltage at 17 A, 25 °C - limits conduction loss to <2.55 W at full RMS current

Pinout & Package

TO-220AB package: 3-terminal through-hole housing with isolated metal tab (A2), lead-free plating, UL94-V0 epoxy, and recommended mounting torque of 0.4–0.6 N·m. Tab is electrically connected to MT2 (A2) terminal.

Pin/Terminal	Circuit Role	Design Meaning
A1 (MT1)	Main Terminal 1	Reference electrode for gate triggering; polarity-sensitive connection point for load return path
A2 (MT2)	Main Terminal 2	Electrically tied to metal tab; primary current path into load; requires insulated heatsink mounting if not referenced to ground
G	Gate	Control input for bidirectional conduction initiation; triggers in Quadrants I, II, and III with ≤35 mA pulse

Key Features

Feature	Design Value
Snubberless operation	Validated (dl/dt)_c ≥ 12 A/ms and dV/dt ≥ 2000 V/µs at 150 °C - removes discrete RC snubber components and associated board space
High-temperature capability	Rated for continuous operation up to 150 °C junction temperature - supports sealed, fanless appliance enclosures
Three-quadrant triggering	Guaranteed IGT ≤ 35 mA in Quadrants I, II, and III - simplifies gate driver design and reduces component count vs. full four-quadrant parts
ECOPACK2 compliance	Halogen-free, RoHS-compliant molding compound with UL94-V0 flammability rating - meets global environmental and safety standards
Robust thermal interface	R_th(j-c) = 1.1 °C/W with metal tab - enables direct mounting to aluminum heatsinks using standard TO-220 hardware

Applications

Universal Motor Control

Resistive Heater Control

Use Scenario: Speed and direction control of vacuum cleaner, power drill, and blender motors using phase-angle dimming.

IC Role / Device Role / Timing Role: Bidirectional AC switch triggered by microcontroller-generated gate pulses synchronized to zero-crossing or phase angle.

Use Value: Eliminates snubber network while sustaining ≥12 A RMS at 150 °C, reducing BOM cost and thermal derating in compact housings.

Use Scenario: On/off and duty-cycle regulation of water heater elements, room heaters, and coffee machine heating plates.

IC Role / Device Role / Timing Role: High-reliability AC line switch enabling precise thermal setpoint control via microcontroller PWM or burst-fire modulation.

Use Value: 800 V blocking voltage and 2000 V/µs dV/dt immunity prevent false triggering during heater element cold-start surges.

Smart AC Plug

Inrush Limiter for AC/DC Rectifiers

Use Scenario: Remote-controlled outlet modules that switch 120/230 VAC loads with embedded Wi-Fi or Zigbee connectivity.

IC Role / Device Role / Timing Role: Primary AC switching element interfaced to isolation driver and MCU; handles both resistive and lightly inductive loads.

Use Value: TO-220AB package provides mechanical stability and thermal headroom for long-term reliability in unventilated plastic enclosures.

Use Scenario: Controlled turn-on of bridge rectifier inputs to limit capacitor charging surge in SMPS and LED drivers.

IC Role / Device Role / Timing Role: Soft-start switch placed between AC input and rectifier bridge; triggered after zero-crossing to minimize peak current.

Use Value: Verified (dl/dt)_c ≥ 12 A/ms ensures clean turn-off without oscillation or latch-up during high di/dt transitions.

Equivalent & Alternatives

The following parts are listed as comparable options for similar triac-based AC line switching applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
BTB12-800CW	12 A/800 V triac in TO-220AB; I_GT ≤ 50 mA; (dl/dt)_c = 10 A/ms at 150 °C; no snubberless certification	Limited to lower-noise environments; requires external snubber for motor loads with fast current decay	Lower-cost option where thermal margin >135 °C and EMI is controlled externally
Q6012LH4	12 A/600 V triac in TO-220AB; I_GT ≤ 35 mA; rated only to 125 °C junction; R_th(j-c) = 1.3 °C/W	Not suitable for 230 VAC continuous operation at elevated ambient; reduced thermal headroom in sealed enclosures	Acceptable for 120 VAC applications with active ventilation and ambient <60 °C

Compared with BTB12-800CW and Q6012LH4, the T1235H-8T uniquely combines 150 °C operation, snubberless certification, and 2000 V/µs dV/dt immunity-making it the only choice for thermally constrained, high-EMI home appliance designs requiring zero-snubber reliability.

Availability

T1235H-8T is available at Aetrix Electronics and suitable for universal motor control, resistive heater regulation, and smart AC plug development requiring stable component supply and long-lifecycle availability.

Supply support for T1235H-8T 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 T1235H-8T belongs to ST's Snubberless Triac product line, engineered specifically for high-temperature, high-noise AC load control in home appliances and industrial equipment where reliability under thermal and electrical stress is critical.

FAQ

What is the maximum allowable case temperature for continuous operation?

The T1235H-8T supports continuous RMS current up to 12 A at T_c = 135 °C, as specified in Absolute Maximum Ratings. Operation beyond this requires derating per Figure 2 in DS13575; the device is qualified for 150 °C junction temperature, but case temperature must remain ≤135 °C to maintain full current rating.

Does the T1235H-8T require a heatsink in typical applications?

Yes-thermal analysis shows R_th(j-a) = 60 °C/W without heatsink, limiting usable power dissipation to ~1.2 W at 25 °C ambient. For 12 A RMS operation, a heatsink with R_th(c-a) ≤ 15 °C/W is required to keep T_j ≤ 150 °C, as shown in Figure 6 of the datasheet.

Can the T1235H-8T be used in zero-crossing switching mode?

Yes-it supports zero-crossing operation in Quadrants I and III, with guaranteed I_GT ≤ 35 mA and V_GT ≤ 1.3 V at 25 °C. Gate drive circuitry must provide ≥100 µs pulse width and respect minimum gate current slew rate to ensure reliable turn-on near voltage zero.

Is the metal tab electrically isolated from the leads?

No-the TO-220AB metal tab is internally connected to A2 (MT2). When mounted to a heatsink, electrical isolation (e.g., mica washer + thermal grease or isolating pad) is mandatory unless A2 is referenced to system ground or chassis potential.

T1235H-8T Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: H

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):: 12 A

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

Current - Non Rep. Surge 50, 60Hz (Itsm):: 120A, 126A

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

Current - Hold (Ih) (Max):: 35 mA

Configuration:: Single

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

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220

T1235H-8T FAQ

1.How can I place an order for T1235H-8T through Aetrix?

Please submit a Request for Quotation (RFQ) for T1235H-8T 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 T1235H-8T reliable?

The price and inventory of T1235H-8T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for T1235H-8T is usually 5 days.

3.What payment methods are accepted for T1235H-8T?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for T1235H-8T transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for T1235H-8T?

T1235H-8T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your T1235H-8T 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 T1235H-8T?

For technical support, including T1235H-8T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your T1235H-8T requirements.

6.How does Aetrix verify that T1235H-8T is sourced from the original manufacturer or authorized distributors?

All T1235H-8T 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 T1235H-8T meets industry standards.

7.What is the process for return or replacement of T1235H-8T?

All T1235H-8T units undergo pre-shipment inspection (PSI). If there is an issue with T1235H-8T, 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 T1235H-8T part is unused and in its original packaging.

Return procedure for T1235H-8T:

1.Submit a request within 90 days.

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

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