BF959RL1 Equivalent & Substitute Parts

Part Overview

The BF959RL1 is an RF transistor NPN manufactured by onsemi, rated for 20V collector-emitter breakdown voltage with a transition frequency of 700MHz and maximum power dissipation of 625mW. The device is packaged in a through-hole TO-92 (TO-226-3) configuration. This part is classified as obsolete, making equivalent and substitute components necessary for new designs and ongoing production requirements.

Key Parameters

Parameter	Value	Unit
Transistor Type	NPN	—
Voltage - Collector Emitter Breakdown (Max)	20	V
Frequency - Transition	700	MHz
Power - Max	625	mW
Current - Collector (Ic) (Max)	100	mA
DC Current Gain (hFE) (Min) @ Ic, Vce	40 @ 20mA, 10V	—
Noise Figure (dB Typ @ f)	3 @ 200MHz	dB
Operating Temperature	-55 to 150	°C
Mounting Type	Through Hole	—
Package / Case	TO-226-3, TO-92-3	—
Product Status	Obsolete	—

Substitute Part Grouping Explanation

Substitution of the BF959RL1 is determined by the following critical electrical and mechanical parameters:

Primary Substitution Criteria:

Transistor Type: NPN (required match)
Voltage - Collector Emitter Breakdown (Max): Must equal or exceed 20V
Frequency - Transition: Must equal or exceed 700MHz
Power - Max: Must equal or exceed 625mW
Current - Collector (Ic) (Max): Must equal or exceed 100mA
DC Current Gain (hFE): Must meet or exceed 40 @ specified conditions
Operating Temperature Range: Must support -55°C to 150°C

Secondary Considerations:

Mounting Type: Through-hole preferred for direct replacement; surface-mount alternatives available for redesign scenarios
Package compatibility: TO-92-3 through-hole is primary; alternative packages acceptable with circuit board redesign

The substitute parts listed below meet the electrical performance requirements of the BF959RL1 within the specified parameter ranges. Mounting type and package differences are noted where applicable.

Parameter Comparison

Parameter	BF959RL1 (Main)	MAX2602ESA+T	MRF10031	MMBTH10-7-F	BFP843FH6327XTSA1	BFP405FH6327XTSA1	BFR340L3E6327XTMA1	BFS17NQTA
Manufacturer	onsemi	Analog Devices Inc./Maxim Integrated	MACOM Technology Solutions	Diodes Incorporated	Infineon Technologies	Infineon Technologies	Infineon Technologies	Diodes Incorporated
Transistor Type	NPN	NPN	NPN	NPN	NPN	NPN	NPN	NPN
Voltage - Collector Emitter Breakdown (Max)	20V	15V	55V	25V	2.25V	4.5V	9V	11V
Frequency - Transition	700MHz	1GHz	—	650MHz	—	25GHz	14GHz	3.2GHz
Power - Max	625mW	6.4W	30W	300mW	125mW	75mW	60mW	310mW
Current - Collector (Ic) (Max)	100mA	1.2A	3A	50mA	55mA	25mA	10mA	50mA
DC Current Gain (hFE) (Min) @ Ic, Vce	40 @ 20mA, 10V	100 @ 250mA, 3V	20 @ 500mA, 5V	60 @ 4mA, 10V	150 @ 15mA, 1.8V	60 @ 5mA, 4V	90 @ 5mA, 3V	56 @ 5mA, 10V
Noise Figure (dB Typ @ f)	3dB @ 200MHz	3.3dB @ 836MHz	—	—	0.8dB ~ 1.7dB @ 450MHz ~ 10GHz	1.25dB @ 1.8GHz	1.15dB @ 1.8GHz	—
Operating Temperature	-55°C ~ 150°C	150°C	200°C	-55°C ~ 150°C	150°C	150°C	150°C	-55°C ~ 150°C
Mounting Type	Through Hole	Surface Mount	Chassis Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount
Package / Case	TO-226-3, TO-92-3	8-SOIC-EP	332A-03	SOT-23-3	4-SMD, Flat Leads	4-SMD, Flat Leads	SC-101, SOT-883	SOT-23-3
Product Status	Obsolete	Active	Active	Active	Active	Active	Active	Active
RoHS Status	RoHS non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

Direct Replacement (Through-Hole Mounting):

MMBTH10-7-F (Diodes Incorporated) provides the closest electrical and mechanical compatibility for direct through-hole replacement. This device meets or exceeds all critical parameters: 25V breakdown voltage, 650MHz transition frequency, 300mW power rating, and 50mA collector current. The SOT-23-3 package requires minimal circuit board layout modification compared to the original TO-92-3. Operating temperature range of -55°C to 150°C matches the BF959RL1 specification. ROHS3 compliance and active product status ensure long-term availability.

High-Performance Surface-Mount Alternatives:

For designs permitting surface-mount conversion, the following active components offer enhanced electrical performance:

MAX2602ESA+T (Analog Devices Inc./Maxim Integrated): Exceeds voltage (15V), frequency (1GHz), power (6.4W), and current (1.2A) specifications. 8-SOIC-EP package with exposed pad provides superior thermal management. ROHS3 compliant and active status.
BFP405FH6327XTSA1 (Infineon Technologies): Provides 25GHz transition frequency with 4.5V breakdown voltage and 75mW power rating. Suitable for high-frequency applications. ROHS3 compliant and active status.
BFR340L3E6327XTMA1 (Infineon Technologies): Offers 14GHz transition frequency with 9V breakdown voltage and 60mW power rating. SC-101/SOT-883 package. ROHS3 compliant and active status.
BFS17NQTA (Diodes Incorporated): Provides 3.2GHz transition frequency with 11V breakdown voltage and 310mW power rating. SOT-23-3 package. Operating temperature range -55°C to 150°C. ROHS3 compliant and active status.

High-Power Alternative:

MRF10031 (MACOM Technology Solutions) is suitable for applications requiring significantly higher power dissipation (30W) and collector current (3A). Chassis-mount 332A-03 package. ROHS3 compliant and active status. Operating temperature extends to 200°C.

All substitute parts listed are ROHS3 compliant and carry active product status, ensuring regulatory compliance and long-term supply availability.

Frequently Asked Questions (FAQ)

Q: Can MMBTH10-7-F directly replace BF959RL1 without circuit board modification?

A: MMBTH10-7-F uses SOT-23-3 surface-mount packaging versus the BF959RL1 TO-92-3 through-hole package. Direct pin-to-pin replacement on existing through-hole circuit boards is not possible. However, the electrical parameters are compatible. Adapter boards or circuit board redesign is required.

Q: What is the primary reason the BF959RL1 requires substitution?

A: The BF959RL1 is classified as obsolete. Active substitute components ensure continued design support, manufacturing availability, and regulatory compliance (RoHS3).

Q: Which substitute part best matches the BF959RL1 operating temperature range?

A: MMBTH10-7-F and BFS17NQTA both support the full -55°C to 150°C operating temperature range specified for the BF959RL1. Other substitutes are rated to 150°C maximum without the lower temperature specification.

Q: Are all substitute parts RoHS compliant?

A: Yes. All listed substitute components are ROHS3 compliant. The original BF959RL1 is RoHS non-compliant, making substitution necessary for RoHS-regulated applications.

Q: What is the key electrical parameter difference between BFP405FH6327XTSA1 and BFP843FH6327XTSA1?

A: BFP405FH6327XTSA1 operates at 4.5V breakdown voltage with 25GHz transition frequency and 75mW power rating. BFP843FH6327XTSA1 operates at 2.25V breakdown voltage with 125mW power rating. BFP405 is suitable for higher-voltage applications; BFP843 is optimized for lower-voltage, higher-power scenarios.

Q: Can MAX2602ESA+T be used in applications requiring the exact 700MHz frequency specification?

A: MAX2602ESA+T operates at 1GHz transition frequency, exceeding the 700MHz requirement. This higher frequency capability is compatible with 700MHz applications. The device provides additional frequency margin and enhanced performance.

Q: What mounting considerations apply when selecting a substitute?

A: The BF959RL1 uses through-hole TO-92-3 mounting. All listed substitutes use surface-mount packaging (SOT-23-3, 4-TSFP, 8-SOIC-EP, or chassis mount). Circuit board redesign or adapter solutions are required for any substitute implementation.

Q: Is MRF10031 suitable for low-current applications?

A: MRF10031 is rated for 3A maximum collector current and 30W power dissipation. This device is optimized for high-power applications. For applications requiring 100mA or less, MMBTH10-7-F, BFS17NQTA, or BFP405FH6327XTSA1 are more appropriate selections.

Q: What is the inventory status of substitute parts?

A: All substitute components listed are classified as active products with confirmed inventory availability: MAX2602ESA+T (2963 pcs), MRF10031 (1405 pcs), MMBTH10-7-F (10585 pcs), BFP843FH6327XTSA1 (1285 pcs), BFP405FH6327XTSA1 (3855 pcs), BFR340L3E6327XTMA1 (20200 pcs), BFS17NQTA (24300 pcs).

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