BUB323Z Equivalent & Substitute Parts

Part Overview

The BUB323Z is an NPN Darlington bipolar junction transistor manufactured by onsemi, designed for high-voltage, high-current switching applications. This component features a 350 V collector-emitter breakdown voltage rating and 10 A maximum collector current capability in a surface mount D2PAK package. The BUB323Z is classified as obsolete, necessitating identification of equivalent substitute components for ongoing design requirements and production continuity.

Substiute Parts

BUB323Z

onsemiIn Stock: 137634BUB323Z Datasheet

Current PartRFQ

BUB941ZTT4

STMicroelectronicsIn Stock: 5458BUB941ZTT4 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the BUB323Z is determined by strict equivalence across the following critical parameters:

Mandatory Matching Parameters:

• Transistor Type: NPN - Darlington configuration
• Voltage - Collector Emitter Breakdown: 350 V minimum
• Package / Case: TO-263-3, D2PAK (2 Leads + Tab)
• Mounting Type: Surface Mount

Allowable Parameter Variations:

• Current - Collector (Ic) (Max): Equal to or greater than 10 A
• Power - Max: Equal to or greater than 150 W
• Operating Temperature: Maximum rating equal to or greater than 175°C

The BUB941ZTT4 manufactured by STMicroelectronics satisfies all mandatory matching parameters and exceeds the allowable variations in collector current (15 A versus 10 A), confirming direct substitution capability.

Parameter Comparison

Engineering Selection Recommendations

BUB323Z (onsemi) - Obsolete Status: The BUB323Z is classified as obsolete and no longer in active production. This status restricts availability for new designs and ongoing production requirements. The component carries RoHS non-compliant certification, which may present regulatory constraints in certain applications and jurisdictions.

BUB941ZTT4 (STMicroelectronics) - Active Status: The BUB941ZTT4 is classified as active and currently in production, ensuring long-term availability and supply chain continuity. This component is ROHS3 compliant and carries automotive-grade qualification, providing enhanced reliability documentation and traceability. The BUB941ZTT4 exceeds the collector current specification of the BUB323Z (15 A versus 10 A) while maintaining identical voltage and power ratings, offering improved design margin for current-limited applications.

For applications requiring component replacement or new designs, the BUB941ZTT4 provides direct functional substitution with the additional benefits of active production status and enhanced regulatory compliance.

Frequently Asked Questions (FAQ)

Q: Can the BUB941ZTT4 directly replace the BUB323Z in existing designs?

A: Yes. Both components share identical voltage ratings (350 V), power dissipation limits (150 W), and D2PAK surface mount packaging. The BUB941ZTT4 provides higher collector current capability (15 A versus 10 A), which is compatible with designs rated for 10 A operation.

Q: What is the significance of the higher collector current rating on the BUB941ZTT4?

A: The BUB941ZTT4 maximum collector current of 15 A exceeds the BUB323Z specification of 10 A. This parameter difference does not prevent substitution; rather, it indicates the substitute component can handle higher current levels without exceeding its maximum ratings. Designs operating at or below 10 A experience no functional change.

Q: Are there packaging differences between these components?

A: No. Both the BUB323Z and BUB941ZTT4 utilize the TO-263-3 D2PAK surface mount package with identical pinout and thermal characteristics. Direct board-level substitution is supported without layout modifications.

Q: What compliance differences exist between these parts?

A: The BUB323Z is RoHS non-compliant, while the BUB941ZTT4 is ROHS3 compliant. For applications subject to RoHS regulations or customer requirements, the BUB941ZTT4 satisfies compliance mandates. Both components are REACH unaffected and carry identical EAR99 export classification.

Q: Does the automotive-grade qualification of the BUB941ZTT4 affect its use in non-automotive applications?

A: No. Automotive-grade qualification indicates enhanced testing and documentation standards. Components qualified to automotive specifications are suitable for general industrial and commercial applications without functional or reliability concerns.

Q: What is the impact of the transition frequency difference?

A: The BUB323Z specifies 2 MHz transition frequency, while the BUB941ZTT4 does not provide this parameter in the available data. For switching applications operating below 2 MHz, both components are functionally equivalent. Applications requiring specific frequency response characteristics should reference detailed datasheets for complete frequency domain specifications.