BC556B,112 Equivalent & Substitute Parts Reference

Part Overview

The BC556B,112 is a PNP bipolar junction transistor manufactured by NXP USA Inc., designed for small-signal switching and amplification applications. It features a maximum collector current of 100 mA, collector-emitter breakdown voltage of 65 V, and power dissipation of 500 mW in a Through Hole TO-92-3 package. The device is classified as obsolete, which necessitates identification of functionally equivalent active alternatives to maintain design continuity and ensure supply chain availability for new production and maintenance applications.

Substiute Parts

BC556B,112

NXP USA Inc.In Stock: 870BC556B,112 Datasheet

Current PartRFQ

BC556ABU

Fairchild SemiconductorIn Stock: 15385BC556ABU Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the BC556B,112 is determined by strict equivalence across the following critical electrical and mechanical parameters:

Electrical Equivalence Criteria:

• Transistor polarity: PNP configuration
• Maximum collector current: 100 mA
• Collector-emitter breakdown voltage: 65 V
• Saturation voltage: 650 mV @ 5 mA, 100 mA
• Collector cutoff current: 15 nA maximum
• Power dissipation: 500 mW
• Operating temperature range: 150°C maximum junction temperature

Mechanical Equivalence Criteria:

• Package type: TO-92-3 (Through Hole)
• Lead configuration: TO-226-3 with formed leads

Compliance Criteria:

• RoHS3 compliance required
• ECCN classification: EAR99
• HTSUS code: 8541.21.0075

The BC556ABU qualifies as a direct substitute based on matching all electrical ratings and mechanical package specifications. Variations in DC current gain (hFE) and transition frequency do not disqualify substitution when the substitute meets or exceeds the minimum specified performance in these parameters.

Parameter Comparison

Engineering Selection Recommendations

BC556ABU Selection Basis:

The BC556ABU is a direct functional equivalent for the obsolete BC556B,112. Selection is justified on the following engineering grounds:

1. Electrical Compatibility: All critical electrical parameters match the original specification. The BC556ABU maintains identical maximum ratings for collector current (100 mA), breakdown voltage (65 V), saturation voltage (650 mV), and power dissipation (500 mW).

2. Package Compatibility: Both devices use the TO-92-3 Through Hole package with identical lead configuration, enabling direct mechanical substitution without PCB redesign.

3. Active Product Status: The BC556ABU is classified as Active, ensuring continued availability and supply chain stability compared to the obsolete BC556B,112.

4. Regulatory Compliance: The BC556ABU maintains equivalent ECCN (EAR99) and HTSUS (8541.21.0075) classifications, preserving export and import compliance requirements.

5. Parameter Variations: The BC556ABU exhibits a lower DC current gain (hFE = 110 minimum versus 220 minimum) and higher transition frequency (150 MHz versus 100 MHz). These variations do not prevent substitution in applications where the original BC556B,112 was specified, as the substitute meets minimum performance thresholds and provides enhanced frequency response.

Frequently Asked Questions (FAQ)

Q: Can the BC556ABU be used as a direct replacement for the BC556B,112 without circuit modification?

A: Yes. The BC556ABU is electrically and mechanically equivalent across all critical parameters. Direct substitution is possible without circuit redesign. The device occupies the same TO-92-3 package and maintains identical maximum ratings for current, voltage, and power dissipation.

Q: What is the significance of the lower DC current gain (hFE) in the BC556ABU?

A: The BC556ABU specifies a minimum hFE of 110 at 2 mA and 5 V, compared to 220 for the BC556B,112. This parameter defines the amplification factor in linear amplification circuits. In switching applications, where the transistor operates in saturation or cutoff, this difference has minimal impact. In linear amplification circuits, the lower gain may require base current adjustment, but the substitute remains functional within the specified operating range.

Q: Does the higher transition frequency of the BC556ABU affect compatibility?

A: No. The BC556ABU transition frequency of 150 MHz exceeds the original 100 MHz specification. Higher transition frequency indicates improved high-frequency performance and does not compromise compatibility with circuits designed for the original device. This represents an enhancement in frequency response capability.

Q: Are there any package or lead configuration differences between these devices?

A: No. Both the BC556B,112 and BC556ABU use the TO-92-3 package with TO-226-3 formed leads. Physical dimensions, lead spacing, and mounting requirements are identical, enabling direct PCB substitution.

Q: What compliance certifications apply to the BC556ABU?

A: The BC556ABU maintains RoHS3 compliance, EAR99 export classification, and HTSUS code 8541.21.0075, matching the regulatory framework of the original BC556B,112. No compliance changes result from substitution.

Q: Is the BC556ABU suitable for new production designs?

A: Yes. The BC556ABU is classified as Active, ensuring long-term availability and supply chain stability. It is appropriate for both maintenance of existing designs using the obsolete BC556B,112 and for new production implementations requiring PNP small-signal transistors with these electrical specifications.