BF494 Equivalent & Substitute Parts

Part Overview

The BF494 is an RF transistor NPN manufactured by onsemi, rated for 20V collector-emitter breakdown voltage with a maximum power dissipation of 350mW in a through-hole TO-92-3 package. This device is classified as obsolete, making equivalent and substitute parts necessary for new designs and production continuity. The BF494 serves RF applications requiring NPN bipolar junction transistor functionality in through-hole form factor.

Substiute Parts

BF494

onsemiIn Stock: 2566BF494 Datasheet

Current PartRFQ

2SC5087R(TE85L,F)

Toshiba Semiconductor and StorageIn Stock: 41762SC5087R(TE85L,F) Datasheet

SimilarRFQ

BFP183WH6327XTSA1

Infineon TechnologiesIn Stock: 15329BFP183WH6327XTSA1 Datasheet

SimilarRFQ

BFP196E6327HTSA1

Infineon TechnologiesIn Stock: 14347BFP196E6327HTSA1 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the BF494 is determined by the following critical parameters: NPN transistor type, maximum collector-emitter breakdown voltage rating, maximum power dissipation capability, maximum collector current rating, and DC current gain characteristics. The substitute parts listed operate at reduced voltage ratings (12V maximum versus 20V) and reduced power dissipation levels (150mW to 700mW versus 350mW), indicating they are suitable for applications with lower voltage and power requirements than the original BF494 specification.

All substitute parts maintain NPN polarity and operate within the 150°C maximum junction temperature range. The substitutes transition from through-hole TO-92-3 packaging to surface-mount packages (SMQ, SOT-343, SOT-143), reflecting modern manufacturing practices. Selection among substitutes depends on specific application requirements for frequency response, gain characteristics, and mounting technology compatibility.

Parameter Comparison

Engineering Selection Recommendations

The BF494 is obsolete; all listed substitutes carry active product status from established manufacturers. Selection among substitutes depends on application voltage and power requirements:

2SC5087R(TE85L,F) operates at 12V maximum with 150mW power dissipation and 80mA maximum collector current. This part is suitable for lower-power RF applications and provides higher DC current gain (120 minimum) compared to the BF494. Operating temperature maximum is 125°C, which is 25°C lower than the BF494 specification.

BFP183WH6327XTSA1 operates at 12V maximum with 450mW power dissipation and 65mA maximum collector current. This part maintains the 150°C operating temperature of the original BF494 and provides specified frequency response (8.5GHz transition frequency) and gain characteristics (22dB). RoHS3 compliance is confirmed.

BFP196E6327HTSA1 operates at 12V maximum with 700mW power dissipation and 150mA maximum collector current. This part provides the highest power handling among substitutes and maintains 150°C operating temperature. Specified frequency response (7.5GHz transition frequency) and gain range (10.5dB to 16.5dB) are provided. RoHS3 compliance is confirmed.

All substitutes require circuit redesign to accommodate surface-mount packaging and reduced voltage ratings. Applications operating above 12V collector-emitter voltage cannot use these substitutes without voltage regulation modifications.

Frequently Asked Questions (FAQ)

Q: Can the BF494 be directly replaced with any of these substitute parts?

A: Direct replacement is not possible due to packaging differences (through-hole versus surface-mount) and reduced voltage ratings (12V versus 20V). Circuit board redesign and voltage specification verification are required.

Q: What is the primary reason for substitution?

A: The BF494 is classified as obsolete. All substitute parts carry active product status from current manufacturers, ensuring long-term availability and supply chain continuity.

Q: Which substitute part most closely matches the BF494 power rating?

A: The BFP183WH6327XTSA1 provides 450mW power dissipation, closest to the BF494's 350mW rating. The BFP196E6327HTSA1 provides 700mW, exceeding the original specification.

Q: Are all substitutes RoHS compliant?

A: The BFP183WH6327XTSA1 and BFP196E6327HTSA1 are RoHS3 compliant. The 2SC5087R(TE85L,F) RoHS status is not specified in the provided data.

Q: What is the impact of reduced voltage rating on circuit design?

A: Applications designed for 20V operation cannot operate these 12V-rated substitutes at the original voltage without external voltage regulation. Circuit analysis is required to determine if reduced voltage operation is acceptable.

Q: How do the operating temperature ranges compare?

A: The BF494 and BFP183WH6327XTSA1 and BFP196E6327HTSA1 all specify 150°C maximum junction temperature. The 2SC5087R(TE85L,F) specifies 125°C maximum, which is 25°C lower.

Q: What packaging considerations apply to these substitutes?

A: All substitutes use surface-mount packages (SMQ, SOT-343, SOT-143) requiring different PCB layout, assembly equipment, and soldering processes compared to the through-hole TO-92-3 package of the BF494.

Q: Are frequency response specifications available for all parts?

A: The BF494 does not specify transition frequency. The 2SC5087R(TE85L,F) specifies 8GHz, BFP183WH6327XTSA1 specifies 8.5GHz, and BFP196E6327HTSA1 specifies 7.5GHz transition frequency.