CQ3P-40M Equivalent & Substitute Parts

Part Overview

The CQ3P-40M is a TRIAC rated for 40A at 600V in TO-3 packaging, manufactured by Central Semiconductor Corp. This component is classified as obsolete, making it necessary to identify functionally equivalent alternatives for new designs and ongoing maintenance applications. Substitute parts must maintain electrical compatibility across voltage, current, and gate trigger specifications to ensure reliable operation in existing circuit topologies.

Substiute Parts

CQ3P-40M

Central Semiconductor CorpIn Stock: 826CQ3P-40M Datasheet

Current PartRFQ

BTA40-600B

STMicroelectronicsIn Stock: 16391BTA40-600B Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

The BTA40-600B qualifies as a direct substitute based on the following critical parameters:

• Voltage Rating (Off State): Both components are rated at 600V, ensuring equivalent voltage withstand capability
• Current Rating (On State): Both components support 40A RMS maximum current, maintaining identical load-handling capacity
• TRIAC Type: Both are standard TRIACs with single configuration, providing equivalent gate control characteristics
• Gate Trigger Parameters: The BTA40-600B gate trigger voltage (Vgt Max: 1.3V) and gate trigger current (Igt Max: 50mA) fall within acceptable operating ranges for circuits designed for the CQ3P-40M

The primary difference is packaging: the CQ3P-40M uses TO-3 (through-hole), while the BTA40-600B uses RD91-3 insulated chassis mount. This substitution requires mechanical redesign of the mounting interface but maintains full electrical compatibility.

Parameter Comparison

Engineering Selection Recommendations

The BTA40-600B is the appropriate substitute for the obsolete CQ3P-40M based on electrical parameter equivalence. The BTA40-600B is actively manufactured by STMicroelectronics, ensuring long-term availability and supply chain stability. The component meets ROHS3 compliance requirements and carries REACH unaffected status, supporting modern manufacturing and environmental standards.

Substitution requires mechanical redesign due to packaging differences. The CQ3P-40M TO-3 through-hole package must be replaced with the BTA40-600B RD91-3 chassis mount configuration. Thermal management characteristics may differ; verify heatsinking requirements based on final application current density and duty cycle.

Frequently Asked Questions (FAQ)

Q: Can the BTA40-600B directly replace the CQ3P-40M without circuit modification?

A: Electrical substitution is valid. The 600V voltage rating and 40A current rating are identical. However, mechanical redesign is required due to packaging differences (TO-3 versus RD91-3 chassis mount). PCB layout and heatsinking must be re-evaluated.

Q: What are the critical parameters for TRIAC substitution?

A: Off-state voltage rating, on-state RMS current rating, gate trigger voltage, and gate trigger current are the primary electrical criteria. For the CQ3P-40M, the 600V/40A specification defines the substitution envelope.

Q: Is the BTA40-600B suitable for new designs?

A: Yes. The BTA40-600B is actively manufactured and meets current compliance standards (ROHS3, REACH unaffected). It is appropriate for both replacement and new design applications.

Q: What is the impact of packaging change from TO-3 to RD91-3?

A: The RD91-3 is an insulated chassis mount package designed for direct mounting to heatsinks. This differs fundamentally from TO-3 through-hole mounting. Thermal performance, mechanical mounting, and PCB layout must be re-engineered for the new package.

Q: Are there inventory considerations for this substitution?

A: The CQ3P-40M is obsolete with limited remaining stock. The BTA40-600B is actively produced with substantial inventory availability, supporting both immediate replacement needs and long-term supply continuity.