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Home > Products > Discrete Semiconductor Products > Thyristors > TRIACs

STMicroelectronics BTB08-400CRG

Name: BTB08-400CRG
Brand: STMicroelectronics
SKU: BTB08-400CRG
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BTB08-400CRG

Manufacturer:: STMicroelectronics

Category:: TRIACs

Package:: TO-220-3

Datasheet:: BTB08-400CRG.pdf

Description:: TRIAC 400V 8A TO220

Quantity:: RFQ Add To RFQ list

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Inventory:9,218

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Product details

Overview

BTB08-400CRG from STMicroelectronics is a 8 A, 400 V RMS snubberless triac in TO-220AB package, designed for AC phase control and ON/OFF 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 (RD), enabling robust motor speed control and heating regulation without external snubbers.

For engineers reviewing the BTB08-400CRG datasheet, BTB08-400CRG pinout, BTB08-400CRG application, or BTB08-400CRG equivalent, key selection criteria include commutation performance under inductive load conditions, gate drive compatibility with microcontrollers, thermal resistance (Rth(j-c) = 1.6 °C/W), and insulation requirements - as this part is non-insulated TO-220AB.

Technical Context

This triac operates in three quadrants (I, II, III) with snubberless commutation capability, supporting reliable turn-off in inductive circuits up to 8 A RMS. Its dV/dt rating of 400 V/µs (min) and critical commutation current rate (dl/dt)c ≥ 7 A/ms (at dV/dt = 10 V/µs) ensure stable operation in motor starting and light dimming applications without snubber networks.

The device uses standard silicon-based thyristor structure with optimized gate sensitivity (IGT ≤ 50 mA) and low holding current (IH ≤ 50 mA), allowing direct interface with logic-level drivers. Junction-to-case thermal resistance of 1.6 °C/W enables high-power dissipation at Tc = 110 °C with appropriate heatsinking.

Key Specifications

Parameter	Value and Actual Design Meaning
IT(RMS)	8 A - Sustained AC load current handling capacity at Tc = 110 °C
VDRM / VRRM	400 V - Peak repetitive off-state voltage blocking capability
IGT (max)	50 mA - Maximum gate current required to trigger conduction reliably
VTM (max)	1.55 V - On-state voltage drop at 11 A pulse, defining conduction loss
Rth(j-c)	1.6 °C/W - Thermal resistance from junction to case, critical for heatsink sizing
dV/dt (min)	400 V/µs - Minimum rate of voltage rise before false triggering occurs
(dl/dt)c	7 A/ms - Critical rate of current decrease ensuring commutation without snubber

Pinout & Package

BTB08-400CRG is housed in a non-insulated TO-220AB package with three terminals: A1 (MT1), A2 (MT2), and G (Gate). The tab is electrically connected to A2 and requires isolation from heatsink unless circuit topology permits common connection.

Pin/Terminal	Circuit Role	Design Meaning
A1 (MT1)	Main Terminal 1	AC load return path; referenced to A2 for bidirectional conduction
A2 (MT2)	Main Terminal 2	AC line input or common terminal; electrically tied to metal tab
G	Gate	Trigger input controlling conduction onset in all active quadrants (I, II, III)

Key Features

Feature	Design Value
Snubberless commutation	Enables reliable turn-off in inductive loads (e.g., motors) without external RC snubber networks
Three-quadrant operation	Supports triggering in quadrants I, II, and III only - reduces false triggering risk vs. 4Q devices
Logic-compatible gate	50 mA IGT max allows direct drive from MCU GPIO pins with minimal buffer circuitry
High dV/dt immunity	400 V/µs minimum ensures noise immunity in noisy industrial AC environments
Low thermal resistance	1.6 °C/W junction-to-case enables compact thermal design at full 8 A RMS rating

Applications

Motor Speed Control

Heating Regulation

Use Scenario: Variable-speed control of single-phase induction motors in fans, pumps, and compressors.

IC Role / Device Role / Timing Role: Bidirectional AC power switch performing phase-angle control to adjust RMS voltage delivered to motor windings.

Use Value: Eliminates need for snubber components while maintaining clean zero-crossing turn-off under inductive back-EMF.

Use Scenario: Precise temperature maintenance in resistive heating elements used in ovens, soldering irons, and HVAC systems.

IC Role / Device Role / Timing Role: ON/OFF or phase-control switch regulating average power to heater based on feedback loop output.

Use Value: 8 A RMS rating supports up to ~1.8 kW at 230 VAC; low VTM minimizes self-heating during continuous conduction.

Light Dimming

Static Relay Replacement

Use Scenario: Mains-powered LED or incandescent lamp brightness adjustment using leading-edge phase-cut dimming.

IC Role / Device Role / Timing Role: AC line switch triggered synchronously with zero-crossing detection to control conduction angle per half-cycle.

Use Value: 400 V VDRM provides margin above 230 VAC peak (325 V); high (dl/dt)c prevents commutation failure during rapid dimming transitions.

Use Scenario: Solid-state replacement for electromechanical relays in programmable logic controllers and industrial I/O modules.

IC Role / Device Role / Timing Role: Fail-safe AC load switching element controlled by isolated digital outputs.

Use Value: Snubberless architecture increases reliability over mechanical contacts; TO-220AB mounting simplifies PCB integration and heatsinking.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
BTB08-400SWRG	10 mA max IGT (vs. 50 mA), same VDRM and IT(RMS)	Better suited for low-power gate drive; requires less current from controller	Select when MCU GPIO current budget is limited or when higher noise immunity is needed due to lower IGT sensitivity
T835-600B	DPAK package (vs. TO-220AB), 35 mA IGT, 600 V VDRM	Surface-mount assembly; higher voltage rating but lower thermal mass	Choose for space-constrained designs requiring SMT placement and where 600 V blocking suffices

Compared with BTB08-400CRG, BTB08-400SWRG offers reduced gate drive burden at the cost of slightly lower noise margin, while T835-600B trades through-hole serviceability and thermal performance for board-area savings and higher voltage headroom.

Availability

BTB08-400CRG is available at Aetrix Electronics and suitable for motor speed control, heating regulation, light dimming, and static relay replacement requiring stable component supply across industrial OEM production cycles.

Supply support for BTB08-400CRG 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, mixed-signal, power, and microcontroller solutions for industrial, automotive, and consumer markets.

BTB08-400CRG belongs to ST's high-reliability snubberless triac product line, engineered specifically for robust AC power control in inductive and resistive load applications where snubber-free operation and gate drive simplicity are essential.

FAQ

Is BTB08-400CRG insulated or non-insulated?

BTB08-400CRG uses a non-insulated TO-220AB package: the metal tab is electrically connected to A2 (MT2). It must be mounted on an isolated heatsink or placed in a circuit where A2 potential is compatible with heatsink grounding. For insulated variants, consider BTA08-xxxS series with "S" suffix.

What is the maximum junction temperature for continuous operation?

The maximum operating junction temperature (Tj) is +125 °C. Derating curves in DS2114 show that full 8 A RMS current is sustainable only when case temperature (Tc) remains ≤110 °C - requiring adequate heatsinking and airflow to maintain safe thermal margins.

Can BTB08-400CRG replace a 4-quadrant triac in existing designs?

No - BTB08-400CRG is a 3-quadrant device (triggering in I, II, III only). It cannot be triggered in quadrant IV, making it unsuitable for legacy circuits relying on full 4Q operation. Verify gate trigger polarity and quadrant support in original schematics before substitution.

Does BTB08-400CRG require a heat sink in all applications?

Yes - at rated 8 A RMS, power dissipation exceeds 12 W (based on VTM and RD). Without a heatsink, junction temperature will exceed 125 °C even at modest ambient temperatures. ST specifies Rth(j-c) = 1.6 °C/W, implying ≥10 °C/W total Rth(j-a) is required for safe operation at full load.

BTB08-400CRG Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: TO-220-3

Packaging:: Tube

Product Status:: Obsolete

Triac Type:: Standard

Voltage - Off State:: 400 V

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

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

Current - Non Rep. Surge 50, 60Hz (Itsm):: 80A, 84A

Current - Gate Trigger (Igt) (Max):: 25 mA

Current - Hold (Ih) (Max):: 25 mA

Configuration:: Single

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

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220

BTB08-400CRG FAQ

1.How can I place an order for BTB08-400CRG through Aetrix?

Please submit a Request for Quotation (RFQ) for BTB08-400CRG 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 BTB08-400CRG reliable?

The price and inventory of BTB08-400CRG are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BTB08-400CRG is usually 5 days.

3.What payment methods are accepted for BTB08-400CRG?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BTB08-400CRG transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BTB08-400CRG?

BTB08-400CRG orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BTB08-400CRG 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 BTB08-400CRG?

For technical support, including BTB08-400CRG datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BTB08-400CRG requirements.

6.How does Aetrix verify that BTB08-400CRG is sourced from the original manufacturer or authorized distributors?

All BTB08-400CRG 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 BTB08-400CRG meets industry standards.

7.What is the process for return or replacement of BTB08-400CRG?

All BTB08-400CRG units undergo pre-shipment inspection (PSI). If there is an issue with BTB08-400CRG, 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 BTB08-400CRG part is unused and in its original packaging.

Return procedure for BTB08-400CRG:

1.Submit a request within 90 days.

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

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