BFS17W,115 Equivalent & Substitute Parts Reference

Part Overview

The BFS17W,115 is an RF transistor NPN manufactured by NXP USA Inc., designed for RF applications requiring operation at 1.6GHz with a maximum power dissipation of 300mW. This device is packaged in SC-70 (SOT-323-3) surface mount configuration and is rated for 15V collector-emitter breakdown voltage with a maximum collector current of 50mA.

The BFS17W,115 is classified as obsolete. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production requirements for applications utilizing this RF transistor.

Substiute Parts

BFS17W,115

NXP USA Inc.In Stock: 770BFS17W,115 Datasheet

Current PartRFQ

BFU550WX

NXP SemiconductorsIn Stock: 4466BFU550WX Datasheet

MFR RecommendedRFQ

BFP640FESDH6327XTSA1

Infineon TechnologiesIn Stock: 3682BFP640FESDH6327XTSA1 Datasheet

MFR RecommendedRFQ

SMMBTH10-4LT3G

onsemiIn Stock: 1081SMMBTH10-4LT3G Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the BFS17W,115 is determined by the following critical parameters:

Primary Substitution Criteria:

• Transistor type: NPN configuration required
• Collector-emitter breakdown voltage: Must equal or exceed 15V
• Maximum collector current: Must support 50mA operation
• Mounting type: Surface mount required
• Package compatibility: SC-70 or equivalent footprint

Secondary Compatibility Factors:

• Frequency transition capability: Minimum 1.6GHz required for RF operation
• Power dissipation: Minimum 300mW required
• DC current gain (hFE): Minimum 25 at specified bias conditions
• Operating temperature range: Must accommodate 175°C maximum junction temperature
• Compliance: RoHS3 compliance preferred for regulatory alignment

The substitute parts identified below meet these criteria with varying performance enhancements in frequency response, gain, and power handling characteristics.

Parameter Comparison

Engineering Selection Recommendations

BFU550WX (NXP Semiconductors)

The BFU550WX is a direct form-factor substitute with SC-70 packaging identical to the BFS17W,115. It provides enhanced RF performance with 11GHz transition frequency and improved noise figure (1.3dB @ 1.8GHz versus 4.5dB @ 500MHz). Power dissipation increases to 450mW, supporting higher output levels. However, the collector-emitter breakdown voltage is reduced to 12V, which is below the 15V specification of the main part. Additionally, this device is RoHS non-compliant and carries obsolete product status. Selection of this substitute requires verification that the 12V voltage rating is acceptable for the target application.

BFP640FESDH6327XTSA1 (Infineon Technologies)

The BFP640FESDH6327XTSA1 is an active-status RF transistor offering exceptional frequency performance at 46GHz with superior noise characteristics (0.55–1.7dB across 150MHz–10GHz). This device is ROHS3 compliant and carries active product status, ensuring long-term availability. However, the collector-emitter breakdown voltage is significantly reduced to 4.7V, and the package format changes to 4-TSFP (4-SMD, Flat Leads), requiring PCB layout redesign. Power dissipation is reduced to 200mW. This substitute is suitable only for applications where voltage headroom is not critical and PCB redesign is feasible.

SMMBTH10-4LT3G (onsemi)

The SMMBTH10-4LT3G is an active-status RF transistor with the highest collector-emitter breakdown voltage (25V) among the substitutes, providing enhanced voltage margin. It is ROHS3 compliant with unlimited moisture sensitivity. However, the transition frequency is reduced to 800MHz, below the 1.6GHz requirement of the main part. The package format is SOT-23-3 (TO-236), differing from the SC-70 footprint. Maximum collector current specification is not provided. This substitute is applicable only to applications where lower frequency operation is acceptable and PCB layout modification is permissible.

Frequently Asked Questions (FAQ)

Q1: Can the BFU550WX directly replace the BFS17W,115 without PCB modifications?

A: The BFU550WX shares identical SC-70 packaging and surface mount configuration, allowing direct footprint compatibility without PCB layout changes. However, the 12V collector-emitter breakdown voltage is lower than the 15V specification of the BFS17W,115. Circuit design must confirm that operating voltages do not exceed 12V. Additionally, RoHS compliance status differs between the two devices.

Q2: What are the key limitations of the BFP640FESDH6327XTSA1 as a substitute?

A: The BFP640FESDH6327XTSA1 requires PCB redesign due to its 4-TSFP package format, which differs from the SC-70 footprint of the BFS17W,115. The collector-emitter breakdown voltage is reduced to 4.7V, restricting application to low-voltage circuits. Power dissipation is also reduced to 200mW. These factors limit its suitability to applications with significant design flexibility and low-voltage operation requirements.

Q3: Is the SMMBTH10-4LT3G suitable for 1.6GHz RF applications?

A: The SMMBTH10-4LT3G has a transition frequency of 800MHz, which is below the 1.6GHz requirement of the BFS17W,115. This device is not suitable for applications requiring 1.6GHz operation. Additionally, the SOT-23-3 package differs from the SC-70 footprint, requiring PCB redesign.

Q4: Which substitute offers the best compliance and long-term availability?

A: The BFP640FESDH6327XTSA1 carries active product status and ROHS3 compliance, ensuring regulatory alignment and extended availability. The BFU550WX and SMMBTH10-4LT3G are also ROHS3 compliant, with the latter also in active status. However, the BFU550WX is classified as obsolete. For applications prioritizing long-term supply chain stability, the BFP640FESDH6327XTSA1 or SMMBTH10-4LT3G are preferred, subject to voltage and frequency requirements.

Q5: What parameters must be verified before selecting a substitute?

A: The following parameters must be confirmed for compatibility: (1) collector-emitter breakdown voltage must meet or exceed circuit operating voltage; (2) transition frequency must support the target RF frequency band; (3) maximum collector current must accommodate circuit bias requirements; (4) package footprint must align with PCB layout or permit redesign; (5) operating temperature range must encompass the application environment; (6) compliance certifications must satisfy regulatory requirements.