CQ3P-40D Equivalent & Substitute Parts

Part Overview

The CQ3P-40D is a TRIAC rated for 40A at 400V in TO-3 packaging, manufactured by Central Semiconductor Corp. This component is classified as obsolete and is no longer in active production. Due to its obsolete status and limited availability, identifying equivalent substitute parts is essential for system redesign, maintenance, and procurement planning. The CQ3P-40D remains functionally relevant for applications requiring medium-voltage thyristor switching, but sourcing alternatives ensures long-term component availability and supply chain continuity.

Substiute Parts

CQ3P-40D

Central Semiconductor CorpIn Stock: 1147CQ3P-40D Datasheet

Current PartRFQ

BTA40-600B

STMicroelectronicsIn Stock: 16391BTA40-600B Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the CQ3P-40D is determined by the following critical parameters:

• Current rating: 40A minimum on-state current (It (RMS))
• Voltage rating: Off-state voltage of 400V or higher
• Device type: TRIAC configuration (single, bidirectional thyristor)
• Thermal and gate characteristics: Compatible gate trigger voltage and current specifications
• Mounting and packaging: Physical form factor suitable for the application circuit

The BTA40-600B qualifies as a direct substitute based on these criteria. It maintains the 40A current rating, exceeds the 400V voltage requirement at 600V, and provides equivalent TRIAC functionality. The higher voltage rating of the BTA40-600B ensures compatibility in applications designed for the CQ3P-40D while offering improved voltage margin.

Parameter Comparison

Engineering Selection Recommendations

The BTA40-600B is the qualified substitute for the CQ3P-40D based on the following engineering criteria:

• Current capacity matches the original specification at 40A
• Voltage rating of 600V exceeds the 400V requirement, providing additional safety margin
• Active product status ensures ongoing availability and supply chain support
• RoHS3 compliance and defined MSL rating (1) meet modern manufacturing and environmental standards
• Single TRIAC configuration maintains functional equivalence for switching applications

The BTA40-600B is suitable for direct replacement in applications where the CQ3P-40D was originally specified, provided that the circuit design accommodates the RD91 chassis mount package and the higher voltage rating does not introduce design constraints.

Frequently Asked Questions (FAQ)

Q: Can the BTA40-600B directly replace the CQ3P-40D in all applications?

A: The BTA40-600B is electrically compatible as a substitute based on current and voltage ratings. However, physical mounting differences between TO-3 and RD91 chassis mount packages require circuit board layout verification. The higher 600V rating is suitable for 400V applications.

Q: What is the significance of the 600V rating on the BTA40-600B compared to the 400V rating of the CQ3P-40D?

A: The 600V off-state voltage rating on the BTA40-600B provides a 200V margin above the original 400V specification. This higher rating does not degrade performance in 400V applications and offers improved reliability under transient voltage conditions.

Q: Are there packaging considerations when substituting the CQ3P-40D with the BTA40-600B?

A: Yes. The CQ3P-40D uses TO-3 packaging, while the BTA40-600B uses RD91-3 insulated chassis mount packaging. Physical dimensions, mounting holes, and thermal interface requirements differ. Circuit board redesign may be necessary to accommodate the different package form factor.

Q: What compliance certifications apply to the BTA40-600B?

A: The BTA40-600B is RoHS3 compliant and REACH unaffected. It carries an ECCN classification of EAR99. These certifications ensure compliance with current environmental and export regulations.

Q: Why is the CQ3P-40D classified as obsolete?

A: The CQ3P-40D is no longer manufactured by Central Semiconductor Corp. Obsolete status indicates end-of-life production and limited remaining inventory. The BTA40-600B from STMicroelectronics represents an active, currently manufactured alternative.