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STMicroelectronics T850-8G
- Part No.:
- T850-8G
- Manufacturer:
- STMicroelectronics
- Category:
- TRIACs
- Package:
- TO-263-3, D2PAK (2 Leads + Tab), TO-263AB
- Datasheet:
-
T850-8G.pdf
- Description:
- TRIAC ALTERNISTOR 800V 8A D2PAK
- Quantity:
- Payment:
- Shipping:
Inventory:9,398
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Product details
Overview
T850-8G from STMicroelectronics is a snubberless, 8 A RMS, 800 V repetitive peak off-state voltage triac in D²PAK package, designed for phase-controlled AC switching in inductive loads. It features 50 mA maximum gate trigger current (IGT), 1.55 V max on-state voltage (VTM) at 11 A, and 50 mΩ dynamic resistance-enabling direct interface with microcontrollers in motor speed controllers and light dimmers.
For engineers reviewing the T850-8G datasheet, T850-8G pinout, T850-8G application, or T850-8G equivalent, key selection criteria include commutation robustness (dV/dt = 1000 V/µs, (dl/dt)c ≥ 4.5 A/ms), thermal resistance (Rth(j-c) = 1.6 °C/W), and snubberless operation on inductive loads without external RC networks.
Technical Context
This triac operates in three quadrants (I, II, III) with snubberless commutation capability, enabling reliable turn-off under high dV/dt transients up to 1000 V/µs at 125 °C junction temperature. Its internal structure eliminates need for external snubbers in inductive load switching.
Designed for logic-level drive compatibility, it accepts gate currents as low as 5% of IGT max (i.e., 2.5 mA typical), supporting direct connection to 3.3 V/5 V MCU GPIOs without buffer stages. The D²PAK package provides 1.6 °C/W junction-to-case thermal resistance for sustained 8 A RMS conduction at Tc = 110 °C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| IT(RMS) | 8 A - Sustained AC load current handling at Tc = 110 °C, suitable for 1 kW resistive or 750 W inductive loads at 230 VAC. |
| VDRM / VRRM | 800 V - Peak blocking voltage per half-cycle, enabling use in 230 VAC mains with 2× safety margin and surge immunity. |
| IGT (max) | 50 mA - Maximum gate trigger current required; enables direct MCU drive with standard GPIO output capability. |
| dV/dt (min) | 1000 V/µs - Critical rate of rise of off-state voltage at 125 °C, ensuring noise-immune commutation on inductive loads without snubber. |
| (dl/dt)c (min) | 4.5 A/ms - Minimum critical rate of decrease of main current at 125 °C, guaranteeing reliable turn-off during zero-crossing transitions. |
| VTM (max) | 1.55 V @ 11 A - On-state voltage drop defining conduction loss (≤17 W at full load), directly impacting heatsink sizing. |
| Rth(j-c) | 1.6 °C/W - Junction-to-case thermal resistance in D²PAK, allowing compact thermal design with minimal copper area. |
Pinout & Package
The T850-8G is housed in a surface-mount D²PAK (TO-263) package with insulated tab rated per UL standards. Thermal performance is optimized for PCB copper area ≥1 cm² under the tab.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A1 | Main Terminal 1 (MT1) | Reference terminal for gate triggering; connected to neutral or low-side AC line in standard configuration. |
| A2 | Main Terminal 2 (MT2) | High-current AC load path terminal; carries full RMS load current and must be routed with wide copper traces. |
| G | Gate | Control input accepting pulsed DC current (5–50 mA); polarity-sensitive relative to A1 for quadrant-specific triggering. |
Key Features
| Feature | Design Value |
|---|---|
| Snubberless commutation | Validated for inductive loads up to 800 V without external RC snubber, reducing BOM count and board space. |
| Logic-level gate drive | IGT ≤ 50 mA with guaranteed 5% minimum at 2.5 mA, enabling direct interface with 3.3 V/5 V microcontrollers. |
| High dV/dt immunity | 1000 V/µs at 125 °C ensures reliable operation in noisy industrial environments with fast-switching loads. |
| D²PAK thermal performance | Rth(j-c) = 1.6 °C/W supports 8 A RMS conduction with compact heatsinking via PCB copper or clip-on heatsink. |
| UL-certified insulation | Internal ceramic pad provides 2500 VRMS isolation between tab and die, meeting safety requirements for Class I equipment. |
Applications
| Motor Speed Control | Light Dimming |
|---|---|
Use Scenario: Variable-speed control of single-phase induction motors in fans, pumps, and compressors using phase-angle firing. IC Role / Device Role / Timing Role: Main AC power switch triggered synchronously with zero-crossing detection to modulate RMS voltage delivered to motor winding. Use Value: Enables precise torque/speed regulation without mechanical gearboxes; snubberless operation prevents false triggering from back-EMF spikes. | Use Scenario: Mains-powered residential and commercial LED/incandescent lamp dimming with leading-edge phase-cut architecture. IC Role / Device Role / Timing Role: Bidirectional AC switch controlled by microcontroller-generated gate pulses aligned to AC waveform zero crossings. Use Value: Delivers flicker-free dimming down to 5% brightness; 800 V rating accommodates 230 VAC + 20% line tolerance and transient surges. |
| Heating Regulation | Static Relay Replacement |
Use Scenario: Solid-state temperature control in electric ovens, soldering irons, and industrial heating elements using burst-fire or phase-control. IC Role / Device Role / Timing Role: High-reliability AC power switch replacing electromechanical relays, driven by PID controller outputs. Use Value: Eliminates contact wear and arcing; 8 A RMS rating supports up to 1.8 kW resistive heating at 230 VAC with no moving parts. | Use Scenario: Isolation and switching of AC loads in PLC I/O modules, HVAC controllers, and building automation systems. IC Role / Device Role / Timing Role: Fail-safe ON/OFF solid-state relay element providing galvanic isolation and fast response versus mechanical counterparts. Use Value: 2500 VRMS insulated tab meets reinforced insulation requirements; 50 mA IGT allows direct drive from optocoupler outputs. |
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 |
|---|---|---|---|
| T835-8G | 35 mA IGT max, 400 V/µs dV/dt, same D²PAK package and 8 A/800 V ratings. | Lower gate sensitivity and reduced commutation margin; suited for less noisy, lower-inductance loads. | Select when gate drive strength exceeds 35 mA and system dV/dt stress is below 400 V/µs. |
| BTA08-800BW | Same 50 mA IGT and 800 V rating but in insulated TO-220AB package; Rth(j-c) = 2.5 °C/W. | Through-hole mounting with higher thermal resistance; requires larger heatsink for equivalent 8 A RMS duty. | Choose for legacy through-hole designs or where creepage/clearance mandates insulated leaded package. |
Compared with T835-8G, T850-8G offers 2.5× higher dV/dt immunity and tighter IGT consistency for noise-prone inductive loads; versus BTA08-800BW, it delivers 39% lower thermal resistance in surface-mount form factor, enabling denser PCB layouts.
Availability
T850-8G is available at Aetrix Electronics and suitable for motor speed control, light dimming, heating regulation, and static relay replacement requiring stable component supply across industrial, appliance, and building automation programs.
Supply support for T850-8G 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 discrete devices, microcontrollers, and analog ICs for industrial, automotive, and consumer markets.
The T8 series belongs to ST's high-reliability snubberless triac product line, engineered specifically for robust AC power control in inductive and resistive loads without external protection components.
FAQ
What is the maximum junction temperature for continuous operation of T850-8G?
The T850-8G has an operating junction temperature range of –40 °C to +125 °C. Continuous conduction at 8 A RMS requires case temperature (Tc) not exceeding 110 °C, verified via thermal design using its 1.6 °C/W junction-to-case resistance and PCB copper area per DS2114 Figure 2.
Does T850-8G require a heat sink in standard applications?
Yes-when conducting 8 A RMS continuously, a heat sink or ≥1 cm² copper pour under the D²PAK tab is mandatory to maintain Tc ≤ 110 °C. At lower currents (e.g., 4 A RMS), natural convection with 2 cm² FR4 copper may suffice per Figure 3 in DS2114.
Can T850-8G replace a standard 4-quadrant triac like BTA08-600B?
No-T850-8G is a 3-quadrant snubberless device optimized for quadrants I, II, and III only. It lacks guaranteed triggering in quadrant IV, making it unsuitable for applications requiring full 4Q symmetry, such as certain analog dimmer IC interfaces.
Is the D²PAK tab of T850-8G electrically insulated?
No-the D²PAK variant (T850-8G) has a non-insulated tab connected to A2. For insulated mounting, select the TO-220AB Insulated version (e.g., BTA08-800BW) which integrates a ceramic pad rated at 2500 VRMS per UL E81734.
T850-8G Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- Snubberless™
- Package/Case:
- TO-263-3, D2PAK (2 Leads + Tab), TO-263AB
- 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):
- 1.2 V
- Current - Non Rep. Surge 50, 60Hz (Itsm):
- 80A, 84A
- Current - Gate Trigger (Igt) (Max):
- 50 mA
- Current - Hold (Ih) (Max):
- 75 mA
- Configuration:
- Single
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- D2PAK
T850-8G FAQ
1.How can I place an order for T850-8G through Aetrix?
Please submit a Request for Quotation (RFQ) for T850-8G 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 T850-8G reliable?
The price and inventory of T850-8G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for T850-8G is usually 5 days.
3.What payment methods are accepted for T850-8G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for T850-8G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for T850-8G?
T850-8G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your T850-8G 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 T850-8G?
For technical support, including T850-8G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your T850-8G requirements.
6.How does Aetrix verify that T850-8G is sourced from the original manufacturer or authorized distributors?
All T850-8G 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 T850-8G meets industry standards.
7.What is the process for return or replacement of T850-8G?
All T850-8G units undergo pre-shipment inspection (PSI). If there is an issue with T850-8G, 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 T850-8G part is unused and in its original packaging.
Return procedure for T850-8G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
T850-8G Tags
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