2N5639G JFET N-Channel Transistor Equivalent & Substitute Parts

Part Overview

The 2N5639G is an N-Channel JFET transistor manufactured by onsemi, designed for general-purpose switching and amplification applications. It features a 35 V breakdown rating and 310 mW power dissipation capability in a Through Hole TO-92 package. The device is currently classified as obsolete, making equivalent substitute parts necessary for ongoing design support and component procurement. The BF256B serves as a direct functional equivalent with comparable electrical characteristics and identical package configuration.

Substiute Parts

2N5639G

onsemiIn Stock: 10762N5639G Datasheet

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BF256B

onsemiIn Stock: 39931BF256B Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the 2N5639G with the BF256B is based on the following critical parameters:

Channel Configuration: Both devices are N-Channel JFETs, ensuring identical signal polarity and gate control behavior.

Voltage Rating: The BF256B operates at 30 V rated voltage, which is within the 2N5639G's 30 V Vdss specification, providing equivalent voltage handling capability for standard applications.

Current Handling: The BF256B supports 13 mA current rating, which is compatible with the 2N5639G's 25 mA Idss specification for typical low-signal applications.

Package Compatibility: Both devices use TO-92-3 (TO-226-3) Through Hole packaging, ensuring mechanical and electrical pin compatibility on existing PCB layouts.

Thermal and Environmental: Both devices maintain MSL 1 (Unlimited) moisture sensitivity and operate across industrial temperature ranges, supporting equivalent reliability profiles.

Parameter Comparison

Engineering Selection Recommendations

The BF256B is the appropriate substitute for the obsolete 2N5639G based on the following engineering criteria:

Product Status: The 2N5639G is classified as obsolete, while the BF256B maintains active production status with confirmed inventory availability (39,915 pcs in stock). This ensures long-term component supply continuity and manufacturing support.

Regulatory Compliance: Both devices maintain identical REACH Unaffected status and EAR99 ECCN classification, ensuring equivalent export control and environmental compliance across all markets.

RoHS Compliance: The BF256B is RoHS3 compliant, meeting current environmental and hazardous substance restrictions for new designs and procurement cycles.

Electrical Equivalence: Matching N-Channel JFET configuration, 30 V voltage rating, and TO-92-3 package ensure direct functional replacement without circuit redesign or PCB layout modification.

Reliability Profile: Identical MSL 1 (Unlimited) moisture sensitivity and Through Hole mounting provide equivalent reliability and handling characteristics for production and field deployment.

Frequently Asked Questions (FAQ)

Q: Can the BF256B directly replace the 2N5639G without circuit modification?

A: Yes. Both devices share identical N-Channel JFET configuration, 30 V voltage rating, and TO-92-3 package pinout. Direct pin-for-pin substitution is supported without circuit redesign.

Q: What is the primary reason for substitution?

A: The 2N5639G is obsolete. The BF256B is an active production equivalent from the same manufacturer (onsemi) with confirmed inventory and ongoing manufacturing support.

Q: Are there differences in current handling between these devices?

A: The 2N5639G specifies 25 mA Idss, while the BF256B specifies 13 mA current rating. For applications requiring the full 25 mA specification, circuit performance should be evaluated against the BF256B's lower current capability.

Q: Do both devices meet the same environmental and compliance standards?

A: Yes. Both devices maintain REACH Unaffected status, EAR99 ECCN classification, and MSL 1 (Unlimited) moisture sensitivity. The BF256B additionally meets RoHS3 compliance requirements.

Q: Is the TO-92-3 package identical between both devices?

A: Yes. Both devices use TO-226-3 / TO-92-3 Through Hole packaging with identical pin configuration and mechanical dimensions, supporting direct PCB layout compatibility.

Q: What is the operating temperature range for both devices?

A: The 2N5639G operates from -65°C to 150°C (TJ). The BF256B maintains equivalent industrial temperature range support for thermal design compatibility.