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Home > Products > Discrete Semiconductor Products > Thyristors > TRIACs

STMicroelectronics T1635T-8T

Name: T1635T-8T
Brand: STMicroelectronics
SKU: T1635T-8T
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: T1635T-8T

Manufacturer:: STMicroelectronics

Category:: TRIACs

Package:: TO-220-3

Datasheet:: T1635T-8T.pdf

Description:: TRIAC ALTERNISTOR 800V 16A TO220

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Product details

Overview

T1635T-8T from STMicroelectronics is a snubberless, three-quadrant triac in TO-220AB package rated for 16 A RMS on-state current, 800 V repetitive peak off-state voltage (V_DRM/V_RRM), and 35 mA gate trigger current (I_GT). It delivers high static/dynamic commutation capability and operates across -40 °C to +150 °C junction temperature, enabling robust AC line switching in motor control and lighting circuits without external snubbers when design limits are observed.

For engineers reviewing the T1635T-8T datasheet, T1635T-8T pinout, T1635T-8T application, or T1635T-8T equivalent, key selection criteria include verified dV/dt immunity (≥1000 V/µs at T_j = 150 °C), critical di/dt rating (8 A/ms at T_j = 150 °C), snubberless operation validation, and TO-220AB thermal resistance (R_th(j-c) = 1.1 °C/W).

Technical Context

The T1635T-8T is a three-quadrant, gate-triggered thyristor designed for phase-angle and zero-crossing AC power control. Its structure supports triggering only in quadrants I, II, and III-excluding quadrant IV-reducing false turn-on from noise while maintaining full half-cycle conduction capability.

It achieves snubberless operation by meeting stringent dV/dt (≥1000 V/µs) and di/dt (≥8 A/ms) thresholds under specified conditions, with validated commutation margins up to 900 V non-repetitive surge (V_DSM/V_RSM) and 126 A surge current (I_TSM) at 60 Hz.

Key Specifications

Parameter	Value and Actual Design Meaning
I_T(RMS)	16 A - Continuous AC load current handling at T_c = 129 °C, defining maximum steady-state power delivery.
V_DRM/V_RRM	800 V - Maximum repetitive blocking voltage at T_j = 125 °C, ensuring safe operation on 230 VAC mains with margin.
I_GT	35 mA - Maximum gate trigger current required to initiate conduction, determining driver circuit strength.
(dV/dt)_c	1000 V/µs - Minimum rate of rise of off-state voltage before spurious turn-on, enabling snubberless use in noisy environments.
(di/dt)_c	8 A/ms - Minimum critical rate of decrease of main current before commutation failure, supporting reliable turn-off in inductive loads.
R_th(j-c)	1.1 °C/W - Junction-to-case thermal resistance, enabling direct heatsink mounting for thermal management.
V_T	1.55 V - Maximum on-state voltage drop at 22.6 A, directly impacting conduction losses and thermal design.

Pinout & Package

Package: TO-220AB - Through-hole, single-ended heat-transfer package with insulated tab, halogen-free epoxy, lead-free plating, and 0.4–0.6 N·m mounting torque specification.

Pin/Terminal	Circuit Role	Design Meaning
A1 (MT1)	Main Terminal 1	Reference terminal for gate trigger polarity; defines quadrant I/II/III conduction paths relative to A2.
A2 (MT2)	Main Terminal 2	Primary current path terminal; voltage referenced to A1 determines triggering quadrant and blocking direction.
G	Gate	Control input for turn-on; requires ≥1.75 mA (min) and ≤35 mA (max) I_GT to ensure reliable triggering across temperature.

Key Features

Feature	Design Value
Snubberless operation	Validated for no external RC snubber when dV/dt < 1000 V/µs and di/dt > 8 A/ms, reducing BOM count and board space.
Three-quadrant triggering	Enables gate control only in quadrants I, II, and III-eliminating quadrant IV sensitivity to noise-induced false turn-on.
High commutation robustness	Supports 900 V non-repetitive surge (V_DSM/V_RSM) and 126 A surge current (I_TSM at 60 Hz), extending reliability in transient-prone AC lines.
ECOPACK2 compliance	Meets RoHS, halogen-free, and lead-free requirements with UL94 V0-rated epoxy, satisfying industrial and consumer environmental mandates.

Applications

Motor Control

Lighting Dimming

Use Scenario: Speed regulation of universal motors in power tools and fans using phase-angle control.

IC Role / Device Role / Timing Role: Main power switch controlling AC energy delivery per half-cycle via gate timing.

Use Value: Eliminates need for snubber networks while sustaining 16 A RMS and 126 A surge, improving efficiency and thermal margin.

Use Scenario: Leading-edge dimming of incandescent and halogen lamps in residential lighting systems.

IC Role / Device Role / Timing Role: Bidirectional AC switch triggered synchronously with zero-crossing or phase-shifted gate pulses.

Use Value: 800 V V_DRM provides safety margin above 230 VAC peak (325 V), and 35 mA I_GT ensures compatibility with standard microcontroller GPIO drivers.

Inrush Current Limiting

Overvoltage Crowbar Protection

Use Scenario: Controlled turn-on of transformer-based power supplies to limit cold-start inrush into capacitive input stages.

IC Role / Device Role / Timing Role: Delayed conduction device activated after soft-start timing, limiting peak current during first few AC cycles.

Use Value: 100 A/µs dl/dt rating prevents false triggering during fast-rising inrush transients, ensuring precise timing window enforcement.

Use Scenario: Fast-acting overvoltage protection in DC bus monitoring circuits, firing to short faulted lines.

IC Role / Device Role / Timing Role: Crowbar element triggered by comparator output upon overvoltage detection, clamping bus to ground.

Use Value: 900 V V_DSM/V_RSM withstands transient surges prior to crowbar activation, preventing premature failure during fault events.

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
BT139-800E	Same 800 V V_DRM, but 16 A I_T(RMS) and 50 mA I_GT; lower dV/dt immunity (600 V/µs typical).	Requires snubber in higher-noise environments; less suitable for snubberless designs.	Select when gate drive margin is available and cost optimization is prioritized over commutation headroom.
TYN616	16 A I_T(RMS), 800 V V_DRM, but two-quadrant (QI/QIII only); 35 mA I_GT and 1000 V/µs dV/dt.	Lacks quadrant II triggering, limiting compatibility with certain zero-crossing driver topologies.	Prefer where simplified triggering logic suffices and quadrant II operation is not required.

Compared with BT139-800E and TYN616, the T1635T-8T uniquely combines three-quadrant operation, 1000 V/µs dV/dt immunity, and validated snubberless performance-making it optimal for noise-sensitive, inductive-load AC control where gate drive simplicity and transient resilience are critical.

Availability

T1635T-8T is available at Aetrix Electronics and suitable for motor control, lighting dimming, and inrush current limiting applications requiring stable component supply, long-term industrial availability, and consistent TO-220AB mechanical form factor.

Supply support for T1635T-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, designing and manufacturing analog, digital, and mixed-signal ICs, discrete devices, and system-on-chip solutions.

The T1635T-8T belongs to ST's high-commutation triac product line, engineered specifically for reliable, snubberless AC power control in cost-sensitive industrial and consumer equipment.

FAQ

Is the T1635T-8T compatible with zero-crossing trigger circuits?

Yes. The T1635T-8T supports zero-crossing operation due to its three-quadrant architecture and guaranteed I_GT ≤ 35 mA at 25 °C. Its dV/dt immunity (≥1000 V/µs at 150 °C) prevents false triggering near voltage zero crossings, making it suitable for solid-state relay and dimmer designs requiring low EMI.

What is the maximum case temperature for continuous 16 A RMS operation?

The datasheet specifies that 16 A RMS operation is rated at T_c = 129 °C. This requires a heatsink capable of maintaining the TO-220AB case below 129 °C under full load, considering R_th(j-c) = 1.1 °C/W and junction limit of 150 °C. Derating is necessary above this case temperature.

Can the T1635T-8T replace a standard four-quadrant triac in existing designs?

No-direct replacement is not recommended unless the original design exclusively uses quadrants I, II, or III. The T1635T-8T excludes quadrant IV triggering, so circuits relying on gate-negative/A2-positive triggering will fail to operate. Verify quadrant usage in legacy schematics before substitution.

Does the "T" suffix in T1635T-8T indicate a specific temperature grade or reliability level?

No. Per ST's ordering scheme, the first "T" denotes increased (di/dt)_c and dV/dt capability, and the final "T" indicates TO-220AB packaging. It does not signify an extended temperature grade-the device operates from -40 °C to +150 °C junction, matching standard industrial grade.

T1635T-8T 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):: 16 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):: 40 mA

Configuration:: Single

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

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220

T1635T-8T FAQ

1.How can I place an order for T1635T-8T through Aetrix?

Please submit a Request for Quotation (RFQ) for T1635T-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 T1635T-8T reliable?

The price and inventory of T1635T-8T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for T1635T-8T is usually 5 days.

3.What payment methods are accepted for T1635T-8T?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for T1635T-8T transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for T1635T-8T?

T1635T-8T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your T1635T-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 T1635T-8T?

For technical support, including T1635T-8T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your T1635T-8T requirements.

6.How does Aetrix verify that T1635T-8T is sourced from the original manufacturer or authorized distributors?

All T1635T-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 T1635T-8T meets industry standards.

7.What is the process for return or replacement of T1635T-8T?

All T1635T-8T units undergo pre-shipment inspection (PSI). If there is an issue with T1635T-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 T1635T-8T part is unused and in its original packaging.

Return procedure for T1635T-8T:

1.Submit a request within 90 days.

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

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