IRKT26/08A SCR Dual Thyristor Module 800V 27A Equivalent & Substitute Parts

Part Overview

The IRKT26/08A is a dual SCR thyristor module manufactured by Vishay General Semiconductor - Diodes Division, rated for 800V off-state voltage with 27A average on-state current and 60A RMS on-state current. This component features series-connected SCRs in an ADD-A-PAK (3 + 4) chassis mount package. The product is currently obsolete, making identification of functionally equivalent alternatives essential for system maintenance, redesign, and procurement planning.

Substiute Parts

IRKT26/08A

Vishay General Semiconductor - Diodes DivisionIn Stock: 1098IRKT26/08A Datasheet

Current PartRFQ

MCC56-08IO1B

IXYSIn Stock: 918MCC56-08IO1B Datasheet

MFR RecommendedRFQ

MCC72-08IO1B

IXYSIn Stock: 692MCC72-08IO1B Datasheet

MFR RecommendedRFQ

MCC95-08IO1B

IXYSIn Stock: 1029MCC95-08IO1B Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the IRKT26/08A is determined by the following critical parameters:

• Voltage Rating: All substitute parts must maintain 800V off-state voltage to ensure equivalent blocking capability
• SCR Configuration: All substitutes must feature dual SCRs in series connection to preserve circuit topology
• Mounting Type: All substitutes must be chassis mount to maintain mechanical compatibility
• Gate Trigger Parameters: Vgt (Max) and Igt (Max) must be compatible with existing gate drive circuitry
• Current Ratings: Substitute parts must meet or exceed the 27A average and 60A RMS on-state current requirements
• Operating Temperature: All substitutes must support the -40°C to 125°C operating range

The three IXYS substitute parts (MCC56-08IO1B, MCC72-08IO1B, MCC95-08IO1B) satisfy these criteria while offering improved current handling and surge capability. These parts transition from the obsolete ADD-A-PAK package to the TO-240AA package, which is a standard industry upgrade path for dual SCR modules.

Parameter Comparison

Engineering Selection Recommendations

MCC56-08IO1B provides the minimum performance upgrade path with 64A average and 100A RMS on-state current ratings. This part maintains the 1.5V gate trigger voltage specification, which differs from the original 2.5V rating and requires gate drive circuit evaluation. The MCC56-08IO1B is suitable for applications where current requirements do not exceed 100A RMS and gate drive circuitry can accommodate the lower trigger voltage.

MCC72-08IO1B and MCC95-08IO1B both offer 180A RMS on-state current capacity with gate trigger parameters matching the original IRKT26/08A specification (2.5V Vgt, 150mA Igt). The MCC72-08IO1B provides 1700A/1800A surge current, while the MCC95-08IO1B provides enhanced surge capability at 2250A/2400A. Both parts are ROHS3 compliant and maintain active product status, ensuring long-term availability and supply chain stability.

All three substitute parts employ the TO-240AA package, which is a widely adopted industry standard for dual SCR modules and offers superior thermal management compared to the obsolete ADD-A-PAK package. The transition to TO-240AA requires mechanical redesign of the mounting interface but provides enhanced reliability and standardization benefits.

Frequently Asked Questions (FAQ)

Q: Can the MCC56-08IO1B be used as a direct replacement for the IRKT26/08A?

A: The MCC56-08IO1B meets the voltage and current requirements but features a 1.5V gate trigger voltage compared to the original 2.5V specification. Gate drive circuitry must be evaluated to confirm compatibility with the lower trigger voltage threshold before implementation.

Q: What is the primary advantage of the TO-240AA package over the ADD-A-PAK package?

A: The TO-240AA package is an industry-standard form factor with improved thermal dissipation characteristics, wider availability, and established supply chain support. The ADD-A-PAK package is obsolete and no longer manufactured by major component suppliers.

Q: Are all three substitute parts electrically interchangeable?

A: All three parts maintain the same 800V voltage rating and dual series-connected SCR configuration. The MCC72-08IO1B and MCC95-08IO1B are directly interchangeable from a gate drive perspective, as both maintain the 2.5V/150mA gate trigger specification. The MCC56-08IO1B requires gate drive circuit evaluation due to its 1.5V trigger voltage.

Q: What is the difference between the MCC72-08IO1B and MCC95-08IO1B?

A: Both parts feature identical on-state current ratings (115A/116A average, 180A RMS) and gate trigger specifications. The primary difference is surge current capability: the MCC95-08IO1B provides 2250A/2400A non-repetitive surge current compared to 1700A/1800A for the MCC72-08IO1B. Selection depends on application surge current requirements.

Q: Do all substitute parts comply with RoHS regulations?

A: Yes, all three IXYS substitute parts (MCC56-08IO1B, MCC72-08IO1B, MCC95-08IO1B) are ROHS3 compliant. The original IRKT26/08A is RoHS non-compliant, making the substitutes suitable for applications with RoHS compliance requirements.

Q: What mechanical modifications are required to implement a substitute part?

A: The transition from ADD-A-PAK to TO-240AA packaging requires redesign of the mounting interface and thermal management system. The TO-240AA package uses a standard three-terminal configuration with different lead spacing and mounting hole patterns compared to the ADD-A-PAK package.