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Home > Products > Discrete Semiconductor Products > Thyristors > TRIACs

STMicroelectronics T435-800B-TR

Name: T435-800B-TR
Brand: STMicroelectronics
SKU: T435-800B-TR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: T435-800B-TR

Manufacturer:: STMicroelectronics

Category:: TRIACs

Package:: TO-252-3, DPAK (2 Leads + Tab), SC-63

Datasheet:: T435-800B-TR.pdf

Description:: TRIAC ALTERNISTOR 800V 4A DPAK

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Product details

Overview

T435-800B-TR from STMicroelectronics is a 4 A, 800 V snubberless three-quadrant triac in DPAK package, designed for AC phase-control switching of inductive loads. It features 35 mA maximum gate trigger current (IGT), 400 V/µs dV/dt immunity at 125 °C, and 50 A/µs critical dI/dt rating - enabling reliable commutation in universal motor and electrovalve circuits without external snubbers.

For engineers reviewing the T435-800B-TR datasheet, T435-800B-TR pinout, T435-800B-TR application, or T435-800B-TR equivalent, key selection criteria include snubberless operation capability, 800 V blocking voltage, thermal resistance (R_th(j-c) = 2.6 °C/W), and DPAK surface-mount compatibility for compact motor control PCBs.

Technical Context

This triac uses ST's Snubberless logic-level technology to achieve high commutation robustness across all three quadrants (I, II, III) without requiring external RC snubber networks. Its 400 V/µs dV/dt rating at 125 °C and 2.5 A/ms (dI/dt)_c at 10 V/µs support direct drive from microcontrollers in noisy AC environments.

The device operates with a low 35 mA max IGT and 35 mA max holding current (I_H), enabling direct interface with standard GPIOs. Its on-state voltage is specified at 1.56 V (max) at 5.5 A and 25 °C, with dynamic resistance under 120 mΩ at 125 °C - ensuring low conduction loss in intermittent-load applications.

Key Specifications

Parameter	Value and Actual Design Meaning
IT(rms)	4 A - Continuous RMS current handling for universal motors up to ~500 W at 230 VAC.
VDRM / VRRM	800 V - Peak repetitive off-state voltage; supports 230 VAC mains with >2× safety margin.
IGT (max)	35 mA - Gate trigger current threshold; compatible with MCU GPIOs without buffer stage.
dV/dt (min)	400 V/µs at 125 °C - Enables snubberless operation in high-noise inductive load switching.
Rth(j-c)	2.6 °C/W - Junction-to-case thermal resistance; enables 4 A operation with minimal heatsinking.
ITSM (50 Hz)	30 A - Non-repetitive surge current for 20 ms; withstands motor startup inrush transients.
VTM (max)	1.56 V at 5.5 A - On-state voltage drop; limits conduction loss to <8.6 W at full RMS current.

Pinout & Package

DPAK (TO-252) package: single-sided heat-dissipating tab, surface-mount footprint, lead-free and halogen-free epoxy molding (UL94 V0). Thermal pad must be soldered to copper area ≥4.95 mm × 6.35 mm for rated current performance.

Pin/Terminal	Circuit Role	Design Meaning
A1 (MT1)	Main Terminal 1	Reference terminal for gate triggering; connected to load return path in phase-control topology.
A2 (MT2)	Main Terminal 2	High-side AC line connection; carries full load current and defines polarity reference for quadrant operation.
G	Gate	Control input for bidirectional conduction initiation; requires ≤35 mA pulse for turn-on in any quadrant.

Key Features

Feature	Design Value
Snubberless operation	Validated at 400 V/µs dV/dt and 2.5 A/ms (dI/dt)_c; eliminates RC network, reducing BOM count and board space.
Three-quadrant triggering	Guaranteed turn-on in Quadrants I, II, and III; enables zero-crossing and phase-angle control with single gate driver.
Logic-level gate sensitivity	Max 35 mA IGT allows direct drive from 3.3 V/5 V MCUs - no external transistor required for most home appliance controllers.
High junction temperature rating	125 °C max operating junction temperature; supports sealed enclosure designs with limited airflow.
Low thermal resistance	R_th(j-c) = 2.6 °C/W enables 4 A continuous operation with minimal copper area (≥3 cm²) on FR4 PCB.

Applications

Universal Motor Control

Electrovalve Actuation

Use Scenario: Speed regulation of vacuum cleaner or power drill motors using phase-angle AC control.

IC Role / Device Role / Timing Role: Main AC power switch triggered by microcontroller-generated gate pulses synchronized to AC zero-crossing.

Use Value: Snubberless design eliminates 2–3 passive components per channel, reducing cost and failure points in high-volume appliances.

Use Scenario: On/off control of solenoid valves in dishwashers and washing machines.

IC Role / Device Role / Timing Role: High-voltage AC switch isolating 230 VAC supply from microcontroller-driven timing logic.

Use Value: 800 V VDRM ensures long-term reliability against mains surges; 35 mA IGT enables direct GPIO drive without level-shifting.

Kitchen Appliance Heating

Power Tool Safety Switching

Use Scenario: Power modulation for induction-compatible cooktop heating elements or fan-assisted ovens.

IC Role / Device Role / Timing Role: Bidirectional AC switch implementing burst-fire or phase-control dimming based on thermal feedback loop.

Use Value: 400 V/µs dV/dt immunity prevents false triggering during rapid load transients common in resistive-inductive hybrid loads.

Use Scenario: Mains isolation and emergency cutoff in corded angle grinders or sanders.

IC Role / Device Role / Timing Role: Fail-safe AC disconnect switch activated by safety controller upon overtemperature or stall detection.

Use Value: 30 A non-repetitive surge rating handles locked-rotor currents; TO-220AB-compatible DPAK fits compact tool PCB layouts.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
BT137-800D	4 A, 800 V, 50 mA IGT, TO-220 package, no snubberless rating specified	Requires external snubber for inductive loads; higher gate drive demand	Select when legacy TO-220 mounting is mandatory and snubber components are acceptable.
T435-800B	Identical specs but in tube packaging (no tape-and-reel); same DPAK footprint and electrical behavior	No difference in circuit function or layout; only differs in logistics format	Select for prototyping or low-volume builds where reel feeding is unnecessary.

Compared with BT137-800D, T435-800B-TR offers verified snubberless operation and lower gate drive burden; compared with T435-800B, it provides automated SMT assembly readiness while maintaining identical thermal and electrical performance.

Availability

T435-800B-TR is available at Aetrix Electronics and suitable for universal motor control, electrovalve actuation, and kitchen appliance heating requiring stable component supply across industrial production cycles.

Supply support for T435-800B-TR 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, power, and microcontroller solutions for industrial, automotive, and consumer markets.

The T4 series belongs to ST's high-reliability AC power switching product line, engineered specifically for snubberless, logic-level triac operation in cost-sensitive, high-volume home appliance and power tool applications.

FAQ

Is T435-800B-TR compatible with zero-crossing SSR drivers?

No - T435-800B-TR is a phase-control triac, not a zero-crossing device. It triggers at programmable points within the AC cycle and lacks internal zero-crossing detection. For zero-crossing operation, ST's H11AA1 optocoupler or dedicated zero-crossing triac drivers (e.g., MOC3041) must be used in conjunction.

What is the minimum gate resistor value for direct MCU drive?

With a 5 V MCU GPIO sourcing 20 mA, a 120 Ω series resistor limits peak gate current to 41.7 mA - safely above the 35 mA max IGT while staying below the 4 A I_GM absolute maximum. For 3.3 V GPIO, use 82 Ω to ensure ≥35 mA under worst-case V_OL.

Can T435-800B-TR replace T410-800B-TR in existing designs?

Yes, with verification of gate drive capability: T435-800B-TR has 35 mA max IGT versus 10 mA for T410-800B-TR, so the existing driver must supply ≥35 mA. All other parameters (VDRM, IT(rms), dV/dt) are identical; thermal design remains unchanged due to same DPAK package and R_th(j-c).

Does the DPAK package require thermal vias under the tab?

Yes - ST recommends ≥4 thermal vias (0.3 mm diameter, filled or plated) connecting the exposed tab pad to an internal or back-side copper plane. Without vias, R_th(j-a) degrades from 70 °C/W to >100 °C/W, risking thermal runaway at 4 A continuous load.

T435-800B-TR Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: Snubberless™

Package/Case:: TO-252-3, DPAK (2 Leads + Tab), SC-63

Packaging:: Tape & Reel (TR)

Product Status:: Active

Triac Type:: Alternistor - Snubberless

Voltage - Off State:: 800 V

Current - On State (It (RMS)) (Max):: 4 A

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

Current - Non Rep. Surge 50, 60Hz (Itsm):: 30A, 31A

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

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

Configuration:: Single

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: DPAK

T435-800B-TR FAQ

1.How can I place an order for T435-800B-TR through Aetrix?

Please submit a Request for Quotation (RFQ) for T435-800B-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 T435-800B-TR reliable?

The price and inventory of T435-800B-TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for T435-800B-TR is usually 5 days.

3.What payment methods are accepted for T435-800B-TR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for T435-800B-TR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for T435-800B-TR?

T435-800B-TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your T435-800B-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 T435-800B-TR?

For technical support, including T435-800B-TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your T435-800B-TR requirements.

6.How does Aetrix verify that T435-800B-TR is sourced from the original manufacturer or authorized distributors?

All T435-800B-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 T435-800B-TR meets industry standards.

7.What is the process for return or replacement of T435-800B-TR?

All T435-800B-TR units undergo pre-shipment inspection (PSI). If there is an issue with T435-800B-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 T435-800B-TR part is unused and in its original packaging.

Return procedure for T435-800B-TR:

1.Submit a request within 90 days.

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

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