2N4400BU Equivalent & Substitute Parts

Part Overview

The 2N4400BU is an NPN bipolar junction transistor (BJT) manufactured by onsemi, designed for general-purpose switching and amplification applications. The device features a maximum collector current of 600 mA, collector-emitter breakdown voltage of 40 V, and maximum power dissipation of 625 mW in a Through Hole TO-92-3 package. The 2N4400BU is classified as obsolete, making identification of functionally equivalent substitute parts essential for ongoing design support, maintenance, and production continuity.

Substiute Parts

2N4400BU

onsemiIn Stock: 10952N4400BU Datasheet

Current PartRFQ

2N4401BU

onsemiIn Stock: 99862N4401BU Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the 2N4400BU is determined by strict equivalence across the following critical electrical and mechanical parameters:

Electrical Equivalence Criteria:

• Transistor type must be NPN
• Maximum collector current (Ic) must be 600 mA or greater
• Collector-emitter breakdown voltage (VCEO) must be 40 V or greater
• Maximum power dissipation must be 625 mW or greater
• Vce saturation characteristics must match or be superior
• Operating temperature range must encompass -55°C to 150°C

Mechanical Equivalence Criteria:

• Package type must be TO-92-3 (TO-226AA)
• Mounting type must be Through Hole
• Pin configuration must be compatible with TO-92-3 standard

The 2N4401BU meets all substitution criteria and is classified as an active product, providing superior availability and ongoing manufacturer support compared to the obsolete 2N4400BU.

Parameter Comparison

Engineering Selection Recommendations

The 2N4401BU is the direct substitute for the 2N4400BU based on electrical and mechanical parameter equivalence. Selection of the 2N4401BU is supported by the following factors:

Product Status: The 2N4401BU is classified as Active, ensuring ongoing manufacturer support, availability, and supply chain continuity. The 2N4400BU is obsolete and subject to inventory depletion.

Compliance & Certifications: The 2N4401BU is RoHS3 Compliant, meeting current environmental and regulatory requirements. Both devices maintain REACH Unaffected status and EAR99 export classification.

Electrical Performance: The 2N4401BU provides equivalent or superior electrical characteristics across all critical parameters. The minimum DC current gain (hFE) of 100 at 150 mA, 1V exceeds the 2N4400BU specification of 50, providing improved circuit performance. Transition frequency specification of 250 MHz is provided for the 2N4401BU, enabling more precise high-frequency circuit design.

Package & Mounting: Both devices utilize identical TO-92-3 (TO-226AA) Through Hole packaging, ensuring direct mechanical and electrical compatibility without PCB redesign or rework.

Frequently Asked Questions (FAQ)

Q: Can the 2N4401BU directly replace the 2N4400BU in existing designs?

A: Yes. The 2N4401BU is electrically and mechanically equivalent to the 2N4400BU. Both devices share identical maximum ratings for collector current (600 mA), collector-emitter breakdown voltage (40 V), power dissipation (625 mW), and operating temperature range (-55°C to 150°C). Package type, pin configuration, and mounting method are identical (TO-92-3 Through Hole). Direct substitution requires no circuit modifications or PCB changes.

Q: What are the key differences between the 2N4400BU and 2N4401BU?

A: The primary differences are product status and specified performance parameters. The 2N4401BU is an active product with current manufacturer support, while the 2N4400BU is obsolete. The 2N4401BU specifies a minimum DC current gain (hFE) of 100 at 150 mA, 1V, compared to 50 for the 2N4400BU, indicating improved amplification characteristics. The 2N4401BU also specifies a transition frequency of 250 MHz. The 2N4401BU is RoHS3 Compliant, meeting current environmental standards.

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

A: No. Both the 2N4400BU and 2N4401BU use the TO-92-3 (TO-226AA) Through Hole package with identical pin configuration. No PCB layout modifications are required for substitution.

Q: Why is the 2N4400BU classified as obsolete?

A: The 2N4400BU is classified as obsolete by the manufacturer, indicating that production has been discontinued and inventory is being depleted. The 2N4401BU serves as the active replacement product, providing equivalent functionality with ongoing manufacturer support and compliance with current environmental regulations.

Q: What is the impact of the higher DC current gain (hFE) in the 2N4401BU?

A: The 2N4401BU minimum DC current gain of 100 at 150 mA, 1V is double that of the 2N4400BU (50 at 150 mA, 1V). This higher gain means the 2N4401BU requires less base current to achieve the same collector current, resulting in improved circuit efficiency and reduced base drive requirements. For most applications, this represents an improvement over the original specification.

Q: Are there compliance or regulatory differences between the two devices?

A: The 2N4401BU is RoHS3 Compliant, meeting current environmental and hazardous substance restrictions. Both devices maintain REACH Unaffected status and EAR99 export classification. The 2N4401BU is the recommended choice for new designs and applications subject to RoHS compliance requirements.

Q: What is the inventory status of these devices?

A: The 2N4400BU has 994 pieces in stock as new original inventory. The 2N4401BU has 9,900 pieces in stock as new original inventory, providing significantly greater availability and supply security for ongoing production and maintenance applications.