Q2008R4 TRIAC 200V 8A TO-220 Equivalent & Substitute Parts

Part Overview

The Q2008R4 is a standard TRIAC rated for 200V off-state voltage and 8A on-state current in a TO-220 through-hole package, manufactured by Littelfuse Inc. This component is classified as obsolete, making identification of equivalent and substitute parts essential for ongoing system support and new design implementations. Substitute parts must maintain functional compatibility within the electrical and mechanical constraints of the original application.

Substiute Parts

Q2008R4

Littelfuse Inc.In Stock: 1023Q2008R4 Datasheet

Current PartRFQ

BT138-600E,127

WeEn SemiconductorsIn Stock: 1114BT138-600E,127 Datasheet

MFR RecommendedRFQ

BTB08-600CRG

STMicroelectronicsIn Stock: 1892BTB08-600CRG Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the Q2008R4 is determined by the following critical parameters:

• Voltage Rating: The substitute must support the application's voltage requirements. The Q2008R4 operates at 200V off-state. Substitutes rated at 600V off-state provide voltage margin and are electrically compatible for 200V applications.
• Current Rating: The substitute must support at least 8A on-state current. Both identified substitutes maintain this 8A minimum rating.
• Gate Trigger Characteristics: Gate trigger voltage (Vgt) and current (Igt) must be compatible with the control circuit. The Q2008R4 specifies Vgt (Max) of 1.3V and Igt (Max) of 25mA.
• Package and Mounting: Both substitutes use TO-220-3 through-hole packaging, maintaining mechanical and thermal interface compatibility.
• TRIAC Type: The Q2008R4 is a standard TRIAC. One substitute (BT138-600E,127) is a logic-sensitive gate variant; the other (BTB08-600CRG) is also standard type.

Parameter Comparison

Engineering Selection Recommendations

BTB08-600CRG (STMicroelectronics) is the primary substitute for direct replacement. This part maintains standard TRIAC type classification, identical gate trigger voltage specification (Vgt Max 1.3V), and matching current rating (8A). The 600V voltage rating provides margin above the original 200V specification. Operating temperature range extends to -40°C, matching the original part. Product status is active with established supply availability. ROHS3 compliance and REACH unaffected status confirm regulatory alignment.

BT138-600E,127 (WeEn Semiconductors) is an alternative substitute with higher current capacity (12A) and lower gate trigger current requirement (10mA). This part is classified as logic-sensitive gate type rather than standard TRIAC. The gate trigger voltage specification (Vgt Max 1.5V) represents a minor deviation from the original 1.3V. Operating temperature specification is limited to 125°C maximum without lower temperature bound documentation. Product status is active. ROHS3 compliance and REACH unaffected status are confirmed.

Both substitutes are ROHS3 compliant and carry EAR99 ECCN classification, matching the regulatory profile of the original Q2008R4.

Frequently Asked Questions (FAQ)

Q: Can BTB08-600CRG directly replace Q2008R4 in existing designs?

A: Yes. BTB08-600CRG maintains identical gate trigger voltage (1.3V max), current rating (8A), and standard TRIAC type. The TO-220-3 package is mechanically and thermally compatible. The 600V voltage rating is suitable for 200V applications.

Q: What is the difference between standard TRIAC and logic-sensitive gate TRIAC?

A: Standard TRIACs require higher gate trigger current (Igt) for reliable triggering. Logic-sensitive gate TRIACs reduce this requirement, enabling operation with lower-power control circuits. The BT138-600E,127 specifies 10mA Igt (Max) versus 25mA for standard types.

Q: Is the higher current rating of BT138-600E,127 (12A vs 8A) a concern?

A: No. Higher current rating does not create incompatibility. The part will operate safely in circuits designed for 8A maximum current. The 12A rating provides additional thermal margin.

Q: Does the 600V rating of substitutes affect circuit operation at 200V?

A: No. Higher voltage rating indicates greater blocking capability. A 600V-rated TRIAC operates safely in 200V applications. The device will not conduct until gate trigger conditions are met, regardless of voltage rating.

Q: Are there temperature range differences between substitutes?

A: Yes. BTB08-600CRG specifies -40°C to 125°C, matching the original Q2008R4. BT138-600E,127 specifies 125°C maximum without documented lower temperature limit. For applications requiring operation below 0°C, BTB08-600CRG is the appropriate choice.

Q: What is the significance of the gate trigger voltage difference (1.3V vs 1.5V)?

A: Gate trigger voltage (Vgt) is a maximum specification. Both values indicate the threshold at which gate current will trigger the TRIAC. A 0.2V difference (1.3V to 1.5V) is within typical control circuit tolerance and does not prevent substitution in standard applications.

Q: Are all three parts available in the same packaging?

A: Yes. Q2008R4, BTB08-600CRG, and BT138-600E,127 all use TO-220-3 through-hole package. Physical footprint and thermal interface are identical, enabling direct PCB mounting compatibility.