BDX33B Equivalent & Substitute Parts

Part Overview

The BDX33B is an NPN Darlington bipolar junction transistor manufactured by onsemi, rated for 80 V collector-emitter breakdown voltage and 10 A maximum collector current in a TO-220 through-hole package. This device is classified as obsolete, necessitating identification of functionally equivalent alternatives for new designs and ongoing production requirements. Substitute parts must maintain electrical compatibility across critical parameters including voltage rating, current capacity, and thermal characteristics while meeting current manufacturing and compliance standards.

Substiute Parts

BDX33B

onsemiIn Stock: 1281BDX33B Datasheet

Current PartRFQ

BDX33BG

onsemiIn Stock: 1239BDX33BG Datasheet

DirectRFQ

2N6388G

onsemiIn Stock: 12342N6388G Datasheet

SimilarRFQ

BDX33C

Fairchild SemiconductorIn Stock: 21693BDX33C Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the BDX33B are classified into two categories based on electrical parameter alignment and product status:

Direct Substitutes maintain identical electrical specifications across all critical parameters: maximum collector current (10 A), collector-emitter breakdown voltage (80 V), maximum power dissipation (70 W), saturation voltage characteristics, and DC current gain. These parts are functionally interchangeable within the same circuit topology.

Similar Substitutes share the same transistor type (NPN Darlington), package format (TO-220-3), and mounting method (through hole), with variations in one or more electrical parameters. These parts require circuit-level evaluation to confirm compatibility.

The key parameters determining substitution eligibility are:

• Transistor Type: NPN - Darlington
• Current - Collector (Ic) (Max): 10 A minimum
• Voltage - Collector Emitter Breakdown (Max): 80 V minimum
• Package / Case: TO-220-3
• Mounting Type: Through Hole

Parameter Comparison

Engineering Selection Recommendations

BDX33BG is the primary direct substitute for the BDX33B. This onsemi part maintains identical electrical specifications across all critical parameters and is classified as active product status. The BDX33BG offers the advantage of ROHS3 compliance, addressing regulatory requirements that the obsolete BDX33B does not meet. Packaging is supplied in tube format, and moisture sensitivity is not applicable. This part is recommended for direct replacement in existing circuit designs without modification.

BDX33C is a similar substitute manufactured by Fairchild Semiconductor. This part shares the same transistor type, package format, and mounting method as the BDX33B. The BDX33C features a higher collector-emitter breakdown voltage rating of 100 V compared to the BDX33B's 80 V, providing enhanced voltage margin in applications. Saturation voltage, DC current gain, and power dissipation characteristics are identical to the BDX33B. The BDX33C is ROHS3 compliant and carries active product status. This part is suitable for applications where the increased voltage rating provides design flexibility.

2N6388G is a similar substitute manufactured by onsemi. While this part maintains the same transistor type, package format, and 10 A collector current rating, it exhibits significant differences in power dissipation (2 W versus 70 W), saturation voltage characteristics, and collector cutoff current. The 2N6388G is not recommended as a substitute for the BDX33B in applications requiring the full 70 W power handling capability. This part is suitable only for low-power applications where thermal and power requirements are substantially reduced.

Frequently Asked Questions (FAQ)

Q: Can the BDX33BG be used as a direct replacement for the BDX33B without circuit modification?

A: Yes. The BDX33BG maintains identical electrical specifications across all critical parameters including collector current (10 A), collector-emitter breakdown voltage (80 V), power dissipation (70 W), saturation voltage, and DC current gain. The TO-220-3 package and through-hole mounting are identical. Direct substitution is supported.

Q: What is the primary advantage of using BDX33BG over the obsolete BDX33B?

A: The BDX33BG is classified as active product status with ROHS3 compliance, ensuring long-term availability and regulatory alignment. The BDX33B is obsolete and non-compliant with current environmental standards.

Q: Is the BDX33C suitable for all applications where the BDX33B is used?

A: The BDX33C is suitable for most applications. The primary difference is the increased collector-emitter breakdown voltage rating (100 V versus 80 V), which provides additional voltage margin. All other critical parameters including current capacity, power dissipation, and saturation characteristics are equivalent. Applications operating near the 80 V limit benefit from the higher rating.

Q: Why is the 2N6388G not recommended as a substitute despite having the same package?

A: The 2N6388G has a maximum power dissipation of 2 W compared to the BDX33B's 70 W. This represents a 35-fold reduction in thermal capacity. Applications requiring sustained power dissipation above 2 W will experience thermal stress and potential device failure with the 2N6388G. This part is suitable only for low-power signal applications.

Q: Are all substitute parts available in the same packaging format?

A: The BDX33BG and 2N6388G are supplied in tube packaging. The BDX33B and BDX33C packaging information is not specified in the available data. All parts use the TO-220-3 package case format and through-hole mounting method.

Q: What compliance certifications should be verified when selecting a substitute?

A: The BDX33BG and BDX33C are both ROHS3 compliant, meeting current environmental regulations. The BDX33B is RoHS non-compliant. For applications subject to RoHS requirements, the BDX33BG or BDX33C must be selected. All parts are REACH unaffected and classified as EAR99 for export control purposes.

Q: Can the BDX33C be used in applications with lower voltage requirements?

A: Yes. The BDX33C's 100 V collector-emitter breakdown voltage rating exceeds the BDX33B's 80 V specification. In applications operating below 80 V, the BDX33C functions identically to the BDX33B with additional voltage margin. No circuit modification is required.