IRKT91/04A Equivalent & Substitute Parts

Part Overview

The IRKT91/04A is an SCR dual module manufactured by Vishay General Semiconductor - Diodes Division, designed for 400V applications with a 95A on-state average current rating. This component features a series connection configuration with one SCR and one diode in an ADD-A-PAK (3 + 4) chassis mount package. The product is currently obsolete, making identification of suitable substitute components essential for ongoing system maintenance and new design implementations.

Key Parameters

Parameter	Value
Voltage - Off State	400 V
Current - On State (It (AV)) (Max)	95 A
Current - On State (It (RMS)) (Max)	210 A
Voltage - Gate Trigger (Vgt) (Max)	2.5 V
Current - Gate Trigger (Igt) (Max)	150 mA
Current - Hold (Ih) (Max)	200 mA
Operating Temperature Range	-40°C to 125°C (TJ)
Mounting Type	Chassis Mount
Package / Case	ADD-A-PAK (3 + 4)

Substitute Part Grouping Explanation

Substitution of the IRKT91/04A is determined by the following critical electrical and mechanical parameters:

Voltage rating must meet or exceed 400V off-state voltage
On-state current capability (both average and RMS) must support the application requirements
Gate trigger voltage and current characteristics must remain within compatible ranges
Hold current specifications must be maintained
Operating temperature range must cover the required thermal envelope
Chassis mount configuration must be preserved for mechanical compatibility
Package form factor must accommodate existing board layouts or allow for mechanical adaptation

The MCC72-08IO1B qualifies as a substitute based on these criteria, with the understanding that higher voltage rating (800V) and modified package configuration (TO-240AA) represent design trade-offs that must be evaluated within the specific application context.

Parameter Comparison

Parameter	IRKT91/04A	MCC72-08IO1B
Manufacturer	Vishay General Semiconductor - Diodes Division	IXYS
Category	Thyristors	Thyristors
Voltage - Off State	400 V	800 V
Current - On State (It (AV)) (Max)	95 A	115 A
Current - On State (It (RMS)) (Max)	210 A	180 A
Voltage - Gate Trigger (Vgt) (Max)	2.5 V	2.5 V
Current - Gate Trigger (Igt) (Max)	150 mA	150 mA
Current - Hold (Ih) (Max)	200 mA	200 mA
Operating Temperature	-40°C to 125°C (TJ)	-40°C to 125°C (TJ)
Mounting Type	Chassis Mount	Chassis Mount
Package / Case	ADD-A-PAK (3 + 4)	TO-240AA
Product Status	Obsolete	Active
RoHS Status	RoHS non-compliant	ROHS3 Compliant

Engineering Selection Recommendations

The MCC72-08IO1B represents an active product alternative to the obsolete IRKT91/04A. Key considerations for selection include:

The substitute component maintains gate trigger specifications (2.5V maximum, 150mA maximum) and hold current (200mA maximum) identical to the original part, ensuring compatible gate drive circuitry. Operating temperature range remains -40°C to 125°C across both components.

The MCC72-08IO1B provides higher off-state voltage rating (800V versus 400V), which offers enhanced overvoltage margin in the application. On-state average current capability increases from 95A to 115A, while RMS current rating decreases from 210A to 180A. These current characteristics must be evaluated against specific application duty cycles.

Package configuration differs between components: the original uses ADD-A-PAK (3 + 4) while the substitute employs TO-240AA. This mechanical difference requires board layout verification and potential mechanical redesign for mounting accommodation.

The MCC72-08IO1B carries ROHS3 compliance status, whereas the IRKT91/04A is RoHS non-compliant. Both components maintain REACH Unaffected status and EAR99 ECCN classification.

Frequently Asked Questions (FAQ)

Q: Can the MCC72-08IO1B directly replace the IRKT91/04A without circuit modifications?

A: Gate trigger voltage and current specifications are identical (2.5V maximum, 150mA maximum), and hold current matches (200mA maximum). However, the higher off-state voltage rating (800V versus 400V) and different package configuration (TO-240AA versus ADD-A-PAK) require mechanical and thermal evaluation within the specific application context.

Q: What is the significance of the voltage rating difference between 400V and 800V?

A: The MCC72-08IO1B's 800V rating provides additional margin above the original 400V specification. Applications operating at or near 400V must verify that the higher voltage rating does not introduce unintended circuit behavior or affect device switching characteristics.

Q: How do the on-state current ratings compare?

A: The IRKT91/04A specifies 95A average and 210A RMS maximum. The MCC72-08IO1B specifies 115A average and 180A RMS maximum. Applications requiring sustained RMS current near 210A must confirm that the 180A RMS rating of the substitute is adequate for the duty cycle.

Q: What are the package compatibility implications?

A: The original ADD-A-PAK (3 + 4) and substitute TO-240AA packages have different physical dimensions and pin configurations. Board layout and mechanical mounting must be verified before implementation. Thermal management characteristics may also differ between packages.

Q: Are there compliance differences between these components?

A: The MCC72-08IO1B is ROHS3 compliant, while the IRKT91/04A is RoHS non-compliant. Both maintain REACH Unaffected status. Compliance requirements of the end application must be considered in component selection.

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