BF959G Equivalent & Substitute Parts

Part Overview

The BF959G is an RF transistor manufactured by onsemi, classified as an NPN bipolar junction transistor (BJT) designed for radio frequency applications. This device operates at a maximum collector-emitter breakdown voltage of 20V with a transition frequency of 700MHz and maximum power dissipation of 625mW. The BF959G is packaged in a Through Hole TO-92 (TO-226-3) configuration and is currently listed as obsolete. Due to its obsolete status, equivalent and substitute parts are necessary for ongoing design support, maintenance, and new production applications requiring RF transistor functionality.

Substiute Parts

BF959G

onsemiIn Stock: 153217BF959G Datasheet

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2SC4215-Y(TE85L,F)

Toshiba Semiconductor and StorageIn Stock: 26702SC4215-Y(TE85L,F) Datasheet

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2SC4726TLP

Rohm SemiconductorIn Stock: 151012SC4726TLP Datasheet

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BFP540ESDH6327XTSA1

Infineon TechnologiesIn Stock: 1480BFP540ESDH6327XTSA1 Datasheet

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BFP650FH6327XTSA1

Infineon TechnologiesIn Stock: 18699BFP650FH6327XTSA1 Datasheet

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BFP760H6327XTSA1

Infineon TechnologiesIn Stock: 800347BFP760H6327XTSA1 Datasheet

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MAX2602ESA+

Analog Devices Inc./Maxim IntegratedIn Stock: 1203MAX2602ESA+ Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the BF959G is determined by electrical and mechanical compatibility within the RF transistor category. The primary substitution criteria are:

Electrical Parameters:

• Transistor type must be NPN
• Voltage rating must equal or exceed 20V collector-emitter breakdown voltage
• Frequency capability must support 700MHz operation
• Power dissipation must accommodate 625mW maximum
• DC current gain and collector current must be compatible with circuit requirements

Mechanical Parameters:

• Mounting type compatibility (Through Hole vs. Surface Mount)
• Package form factor and pin configuration

The substitute parts listed below are grouped into two categories: Through Hole compatible substitutes (direct mechanical replacement) and Surface Mount alternatives (electrical equivalents requiring circuit board redesign). Surface Mount substitutes are included because they provide equivalent or superior electrical performance for RF applications, though they require different PCB layout and assembly methods.

Parameter Comparison

Engineering Selection Recommendations

Product Status Consideration: The BF959G is obsolete, making substitute selection necessary for continued component availability. All listed substitute parts are in active production status, ensuring long-term supply chain viability and ongoing manufacturer support.

Compliance and Certifications: All substitute parts listed are ROHS3 compliant and REACH unaffected, meeting current environmental and regulatory requirements. The BF959G's compliance status is not specified in available documentation.

Electrical Compatibility Assessment:

1. 2SC4215-Y(TE85L,F) — Provides 30V voltage rating (exceeds 20V requirement) and 550MHz frequency capability. Reduced maximum collector current (20mA vs. 100mA) and power dissipation (100mW vs. 625mW) limit applicability to lower-power RF circuits. Surface Mount package requires PCB redesign.

2. 2SC4726TLP — Provides 3.2GHz frequency capability, exceeding 700MHz requirement. Voltage rating of 11V is below the 20V specification and restricts use to lower-voltage applications. Maximum collector current of 50mA is reduced. Surface Mount package requires PCB redesign.

3. BFP540ESDH6327XTSA1 — Provides 30GHz frequency capability with superior noise figure (0.9dB ~ 1.4dB). Voltage rating of 5V is significantly below 20V specification, restricting use to low-voltage RF applications. Maximum collector current of 80mA is reduced. Surface Mount package requires PCB redesign.

4. BFP650FH6327XTSA1 — Provides 42GHz frequency capability with superior noise figure and gain characteristics. Voltage rating of 4.5V is significantly below 20V specification. Maximum collector current of 150mA exceeds BF959G capability. Surface Mount package requires PCB redesign.

5. BFP760H6327XTSA1 — Provides 45GHz frequency capability with superior noise figure (0.5dB ~ 0.95dB) and gain (16.5dB ~ 29dB). Voltage rating of 4V is significantly below 20V specification. Maximum collector current of 70mA is reduced. Surface Mount package requires PCB redesign.

6. MAX2602ESA+ — Provides 1GHz frequency capability, exceeding 700MHz requirement. Voltage rating of 15V is below 20V specification. Maximum collector current of 1.2A and power dissipation of 6.4W significantly exceed BF959G capabilities, suitable for higher-power RF applications. Surface Mount 8-SOIC package requires PCB redesign.

Selection Guidance: For applications requiring voltage ratings at or above 20V, the 2SC4215-Y(TE85L,F) with 30V rating is the most suitable electrical equivalent, though it operates at reduced power levels. For applications where voltage constraints are less critical and higher frequency performance is beneficial, the Infineon BFP-series transistors (BFP540, BFP650, BFP760) provide superior RF performance characteristics. The MAX2602ESA+ is appropriate for higher-power RF applications where the 15V rating is acceptable.

Frequently Asked Questions (FAQ)

Q: Can the BF959G be directly replaced with a Surface Mount substitute without circuit modification?

A: No. The BF959G is a Through Hole TO-92 package device. All listed substitute parts are Surface Mount devices requiring PCB layout redesign, different assembly methods, and potential circuit topology adjustments. Direct mechanical substitution is not possible.

Q: Which substitute part most closely matches the BF959G electrical specifications?

A: The 2SC4215-Y(TE85L,F) provides the closest voltage rating match at 30V (exceeding the 20V requirement) and operates within the RF frequency range. However, it has reduced maximum collector current (20mA vs. 100mA) and power dissipation (100mW vs. 625mW), limiting it to lower-power applications.

Q: Are all substitute parts suitable for 20V operation?

A: No. Only the 2SC4215-Y(TE85L,F) with 30V rating and MAX2602ESA+ with 15V rating can operate at or near the BF959G's 20V specification. The Infineon BFP-series transistors (BFP540, BFP650, BFP760) have voltage ratings between 4V and 5V and are restricted to low-voltage RF applications.

Q: What is the primary advantage of the Infineon BFP-series substitutes?

A: The BFP-series transistors (BFP540, BFP650, BFP760) provide significantly higher transition frequencies (30GHz to 45GHz) and superior noise figure characteristics compared to the BF959G's 700MHz specification. These devices are optimized for high-frequency RF applications where the lower voltage ratings are acceptable.

Q: Can the MAX2602ESA+ handle higher power levels than the BF959G?

A: Yes. The MAX2602ESA+ has a maximum power dissipation of 6.4W, significantly exceeding the BF959G's 625mW rating. It also supports maximum collector current of 1.2A compared to the BF959G's 100mA, making it suitable for higher-power RF amplification circuits.

Q: What compliance certifications should I verify for substitute parts?

A: All listed substitute parts are ROHS3 compliant and REACH unaffected, meeting current environmental regulations. Verify that your application requirements align with these certifications before final component selection.

Q: Does package type affect RF performance?

A: Yes. Surface Mount packages (SC-70, SC-75, SOT-343, 8-SOIC) have different parasitic characteristics and PCB layout requirements compared to Through Hole TO-92 packages. PCB design must account for these differences to maintain RF performance specifications.

Q: Which substitute part has the lowest noise figure?

A: The BFP760H6327XTSA1 provides the lowest noise figure at 0.5dB ~ 0.95dB measured at 900MHz ~ 5.5GHz, compared to the BF959G's 3dB @ 200MHz. This makes it suitable for low-noise RF receiver applications where voltage constraints are acceptable.