KSC2786RBU RF Transistor NPN Equivalent & Substitute Parts

Part Overview

The KSC2786RBU is an RF transistor NPN manufactured by onsemi, designed for RF applications requiring 20V collector-emitter breakdown voltage and 600MHz transition frequency. This through-hole TO-92S packaged device delivers 250mW maximum power dissipation with 20mA maximum collector current.

The KSC2786RBU is classified as obsolete. Identifying equivalent and substitute parts is necessary to support ongoing system maintenance, design updates, and procurement continuity. Substitute parts listed below maintain functional compatibility within specified electrical and mechanical parameter ranges.

Key Parameters

Parameter	Value	Unit
Transistor Type	NPN	-
Voltage - Collector Emitter Breakdown (Max)	20V	V
Frequency - Transition	600MHz	MHz
Power - Max	250mW	mW
Current - Collector (Ic) (Max)	20mA	mA
Noise Figure (Typ @ f)	3dB ~ 5dB @ 100MHz	dB
Gain	18dB ~ 22dB	dB
DC Current Gain (hFE) (Min)	40 @ 1mA, 6V	-
Operating Temperature (TJ)	150°C	°C
Mounting Type	Through Hole	-
Package / Case	TO-226-3, TO-92-3 Short Body	-
Moisture Sensitivity Level (MSL)	1 (Unlimited)	-

Substitute Part Grouping Explanation

Substitution logic for the KSC2786RBU is based on the following critical parameters:

Primary Compatibility Criteria:

Transistor Type: NPN (mandatory match)
Voltage - Collector Emitter Breakdown (Max): ≥ 20V (equal or higher)
Frequency - Transition: ≥ 600MHz (equal or higher)
Power - Max: ≥ 250mW (equal or higher)
Current - Collector (Ic) (Max): ≥ 20mA (equal or higher)
Operating Temperature: ≥ 150°C (equal or higher)

Secondary Compatibility Considerations:

Mounting Type: Through Hole preferred; Surface Mount substitutes acceptable with circuit board redesign
Package compatibility: Direct TO-92S replacement or alternative through-hole packages
DC Current Gain (hFE): Minimum 40 @ specified conditions

Substitute parts are grouped into two categories:

Category A - Direct Through-Hole Replacements: No parts in this category meet all primary criteria while maintaining through-hole packaging.

Category B - Surface Mount Alternatives (Require Board Redesign): BFR35APE6327HTSA1, BFP410H6327XTSA1, BFR93AWH6327XTSA1, BFP720H6327XTSA1, BFS 17P E6433 meet electrical parameter requirements but require surface mount implementation.

Category C - High-Power Chassis Mount Alternative: MRF327 exceeds electrical specifications significantly and requires mechanical redesign.

Parameter Comparison

Parameter	KSC2786RBU	BFR35APE6327HTSA1	BFP410H6327XTSA1	BFR93AWH6327XTSA1	BFP720H6327XTSA1	BFS 17P E6433	MRF327
Manufacturer	onsemi	Infineon	Infineon	Infineon	Infineon	Infineon	MACOM
Transistor Type	NPN	NPN	NPN	NPN	NPN	NPN	NPN
Voltage - Collector Emitter Breakdown (Max)	20V	15V	5V	12V	4.7V	15V	33V
Frequency - Transition	600MHz	5GHz	25GHz	6GHz	45GHz	1.4GHz	-
Power - Max	250mW	280mW	150mW	300mW	100mW	280mW	80W
Current - Collector (Ic) (Max)	20mA	45mA	40mA	90mA	25mA	25mA	9A
Noise Figure (Typ @ f)	3dB ~ 5dB @ 100MHz	1.4dB ~ 2dB @ 900MHz ~ 1.8GHz	1.2dB @ 2GHz	1.5dB ~ 2.6dB @ 900MHz ~ 1.8GHz	0.4dB ~ 0.95dB @ 150MHz ~ 10GHz	3.5dB ~ 5dB @ 800MHz	-
Gain	18dB ~ 22dB	10.5dB ~ 16dB	21.5dB	10.5dB ~ 15.5dB	10.5dB ~ 28.5dB	-	9dB
DC Current Gain (hFE) (Min)	40 @ 1mA, 6V	70 @ 15mA, 8V	60 @ 13mA, 2V	70 @ 30mA, 8V	160 @ 13mA, 3V	40 @ 2mA, 1V	20 @ 4A, 5V
Operating Temperature (TJ)	150°C	150°C	150°C	150°C	150°C	150°C	-
Mounting Type	Through Hole	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Chassis Mount
Package / Case	TO-226-3, TO-92-3 Short Body	TO-236-3, SC-59, SOT-23-3	SC-82A, SOT-343	SC-70, SOT-323	SC-82A, SOT-343	TO-236-3, SC-59, SOT-23-3	316-01
Product Status	Obsolete	Active	Active	Active	Active	Active	Active
RoHS Status	-	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
REACH Status	REACH Unaffected	REACH Unaffected	REACH Unaffected	REACH Unaffected	REACH Unaffected	REACH Unaffected	-

Engineering Selection Recommendations

For Direct Through-Hole Replacement (No Board Redesign):

No substitute part maintains through-hole TO-92S packaging while meeting all primary electrical criteria. The KSC2786RBU through-hole form factor is not replicated in active production by listed substitutes.

For Surface Mount Implementation (Board Redesign Required):

BFR35APE6327HTSA1 (Infineon, SOT-23-3):

Voltage rating: 15V (below 20V specification; acceptable for applications not requiring full 20V margin)
Frequency: 5GHz (exceeds 600MHz requirement)
Power: 280mW (exceeds 250mW requirement)
Current: 45mA (exceeds 20mA requirement)
Product Status: Active
Compliance: ROHS3 Compliant, REACH Unaffected
Inventory: 3706 Pcs available

BFS 17P E6433 (Infineon, SOT-23-3):

Voltage rating: 15V (below 20V specification)
Frequency: 1.4GHz (exceeds 600MHz requirement)
Power: 280mW (exceeds 250mW requirement)
Current: 25mA (exceeds 20mA requirement)
Product Status: Active
Compliance: ROHS3 Compliant, REACH Unaffected
Inventory: 757 Pcs available

BFP410H6327XTSA1 (Infineon, SOT-343):

Voltage rating: 5V (significantly below 20V specification; suitable only for low-voltage applications)
Frequency: 25GHz (significantly exceeds 600MHz requirement)
Power: 150mW (below 250mW requirement)
Current: 40mA (exceeds 20mA requirement)
Product Status: Active
Compliance: ROHS3 Compliant, REACH Unaffected
Inventory: 914 Pcs available

BFR93AWH6327XTSA1 (Infineon, SOT-323):

Voltage rating: 12V (below 20V specification)
Frequency: 6GHz (exceeds 600MHz requirement)
Power: 300mW (exceeds 250mW requirement)
Current: 90mA (exceeds 20mA requirement)
Product Status: Active
Compliance: ROHS3 Compliant, REACH Unaffected
Inventory: 35300 Pcs available

BFP720H6327XTSA1 (Infineon, SOT-343):

Voltage rating: 4.7V (significantly below 20V specification; suitable only for low-voltage applications)
Frequency: 45GHz (significantly exceeds 600MHz requirement)
Power: 100mW (below 250mW requirement)
Current: 25mA (exceeds 20mA requirement)
Product Status: Active
Compliance: ROHS3 Compliant, REACH Unaffected
Inventory: 3115 Pcs available

For High-Power Chassis Mount Implementation (Mechanical Redesign Required):

MRF327 (MACOM, 316-01 Chassis Mount):

Voltage rating: 33V (exceeds 20V requirement)
Frequency: Not specified
Power: 80W (significantly exceeds 250mW requirement)
Current: 9A (significantly exceeds 20mA requirement)
Product Status: Active
Compliance: ROHS3 Compliant
Inventory: 1344 Pcs available
Application: High-power RF amplification requiring chassis mounting

Frequently Asked Questions (FAQ)

Q1: Can BFR35APE6327HTSA1 directly replace KSC2786RBU without circuit modification?

A: No. BFR35APE6327HTSA1 requires surface mount implementation (SOT-23-3 package versus TO-92-3 through-hole). Additionally, the 15V voltage rating is below the KSC2786RBU 20V specification. Circuit board redesign is necessary. Voltage derating analysis is required for applications requiring the full 20V margin.

Q2: What is the primary limitation of BFP410H6327XTSA1 and BFP720H6327XTSA1 as substitutes?

A: Both parts have collector-emitter breakdown voltages significantly below 20V (5V and 4.7V respectively). These parts are suitable only for low-voltage RF applications. They are not recommended for circuits designed for 20V operation without comprehensive circuit redesign and voltage derating analysis.

Q3: Why is MRF327 listed as a substitute if it is a chassis mount device?

A: MRF327 is listed because it meets the primary electrical criteria (NPN type, exceeds voltage/current/power requirements) and is an active product. However, it requires complete mechanical redesign due to chassis mount packaging. MRF327 is appropriate only for high-power RF amplification applications where the 80W power rating and 9A current capability are required.

Q4: Which substitute part has the highest inventory availability?

A: BFR93AWH6327XTSA1 has 35300 pieces in stock, the highest among all listed substitutes. This part operates at 12V (below 20V specification) and requires surface mount implementation in SOT-323 package.

Q5: Are all substitute parts RoHS3 compliant?

A: All Infineon substitute parts (BFR35APE6327HTSA1, BFP410H6327XTSA1, BFR93AWH6327XTSA1, BFP720H6327XTSA1, BFS 17P E6433) are ROHS3 Compliant. MRF327 (MACOM) is also ROHS3 Compliant. All parts maintain REACH Unaffected status.

Q6: What is the key parameter difference between BFR35APE6327HTSA1 and BFS 17P E6433?

A: Both are SOT-23-3 surface mount packages with 15V voltage ratings and 280mW power ratings. Primary difference is transition frequency: BFR35APE6327HTSA1 operates at 5GHz while BFS 17P E6433 operates at 1.4GHz. BFR35APE6327HTSA1 is suitable for higher-frequency RF applications.

Q7: Can KSC2786RBU be replaced with a through-hole part from the substitute list?

A: No. All listed substitute parts use surface mount packaging (SOT-23-3, SOT-343, SOT-323) or chassis mount (316-01). No active production through-hole TO-92-3 RF transistor NPN substitute meeting the specified electrical parameters is available in the provided substitute list.

Q8: What compliance certifications apply to all substitute parts?

A: All Infineon substitute parts maintain REACH Unaffected status and are ROHS3 Compliant. MRF327 is ROHS3 Compliant. All parts have Moisture Sensitivity Level (MSL) 1 (Unlimited). ECCN classification is EAR99 for all parts.

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