KSC1815YBU Equivalent & Substitute Parts

Part Overview

The KSC1815YBU is an NPN bipolar junction transistor manufactured by onsemi, rated for 50V collector-emitter breakdown voltage and 150mA maximum collector current. This device is packaged in a TO-92-3 through-hole configuration and is classified as obsolete. Due to its obsolete status, equivalent substitute parts with active product status are necessary for new designs and ongoing production requirements. Substitute parts must maintain electrical and mechanical compatibility within the specified parameter ranges.

Key Parameters

Parameter	Value	Unit
Transistor Type	NPN	—
Voltage - Collector Emitter Breakdown (Max)	50	V
Current - Collector (Ic) (Max)	150	mA
Power - Max	400	mW
Frequency - Transition	80	MHz
Mounting Type	Through Hole	—
Package / Case	TO-92-3	—
Operating Temperature (Max)	150	°C

Substitute Part Grouping Explanation

Substitution eligibility for the KSC1815YBU is determined by the following critical parameters: transistor type (NPN), collector-emitter breakdown voltage (50V maximum), collector current rating (150mA maximum), power dissipation (400mW maximum), transition frequency (80MHz minimum), through-hole mounting configuration, and TO-92-3 package compatibility.

Substitute parts are grouped into two categories:

Category 1: Direct Electrical Equivalents — Parts that match all primary electrical specifications and maintain identical or superior performance characteristics within the defined parameter envelope.

Category 2: Higher-Performance Alternatives — Parts that exceed the KSC1815YBU specifications in one or more parameters while maintaining backward compatibility in circuit applications designed for the original part.

The KSC1815YTA qualifies as a direct equivalent with active product status. The 2N6428 PBFREE qualifies as a higher-performance alternative, offering increased current and power ratings while maintaining voltage and package compatibility.

Parameter Comparison

Parameter	KSC1815YBU	KSC1815YTA	2N6428 PBFREE
Manufacturer	onsemi	onsemi	Central Semiconductor Corp
Product Status	Obsolete	Active	Active
Transistor Type	NPN	NPN	NPN
Voltage - Collector Emitter Breakdown (Max)	50 V	50 V	50 V
Current - Collector (Ic) (Max)	150 mA	150 mA	200 mA
Power - Max	400 mW	400 mW	1.5 W
Frequency - Transition	80 MHz	80 MHz	100 MHz
Mounting Type	Through Hole	Through Hole	Through Hole
Package / Case	TO-92-3	TO-92-3	TO-92-3
Operating Temperature (Max)	150°C	150°C	150°C
Vce Saturation (Max) @ Ib, Ic	250mV @ 10mA, 100mA	250mV @ 10mA, 100mA	600mV @ 5mA, 100mA
DC Current Gain (hFE) (Min) @ Ic, Vce	120 @ 2mA, 6V	70 @ 2mA, 6V	250 @ 10mA, 5V
Current - Collector Cutoff (Max)	100nA	100nA	25nA
RoHS Status	Not specified	ROHS3 Compliant	ROHS3 Compliant
REACH Status	REACH Unaffected	REACH Unaffected	REACH Unaffected

Engineering Selection Recommendations

KSC1815YTA is the primary substitute for the obsolete KSC1815YBU. Both parts are manufactured by onsemi and share identical electrical specifications across all critical parameters: 50V breakdown voltage, 150mA collector current, 400mW power dissipation, and 80MHz transition frequency. The KSC1815YTA maintains active product status and ROHS3 compliance, making it suitable for new designs and production continuity. The primary difference is packaging format (cut tape versus bulk), which does not affect electrical performance or circuit compatibility.

2N6428 PBFREE is a higher-performance alternative manufactured by Central Semiconductor Corp. This part exceeds the KSC1815YBU specifications in collector current (200mA versus 150mA), power dissipation (1.5W versus 400mW), and transition frequency (100MHz versus 80MHz). The 2N6428 PBFREE maintains the same 50V breakdown voltage and TO-92-3 package configuration. This part is suitable for applications requiring higher current capacity or power handling while operating within the same voltage envelope. The 2N6428 PBFREE is ROHS3 compliant and maintains active product status.

Both substitute parts are REACH unaffected and carry EAR99 export classification, matching the compliance profile of the original KSC1815YBU.

Frequently Asked Questions (FAQ)

Q: Can the KSC1815YTA directly replace the KSC1815YBU in existing circuits?

A: Yes. The KSC1815YTA is electrically equivalent to the KSC1815YBU across all critical parameters: 50V breakdown voltage, 150mA maximum collector current, 400mW power dissipation, and 80MHz transition frequency. Both parts are NPN transistors in TO-92-3 packages with identical pin configurations. The KSC1815YTA is the recommended direct replacement due to its active product status and identical electrical specifications.

Q: What are the differences between KSC1815YTA and 2N6428 PBFREE?

A: The KSC1815YTA matches the KSC1815YBU specifications exactly. The 2N6428 PBFREE offers higher performance: 200mA collector current (versus 150mA), 1.5W power dissipation (versus 400mW), and 100MHz transition frequency (versus 80MHz). Both maintain 50V breakdown voltage and TO-92-3 packaging. The 2N6428 PBFREE is suitable for applications requiring higher current or power handling within the same voltage rating.

Q: Are there DC current gain differences between these parts?

A: Yes. The KSC1815YBU specifies minimum DC current gain (hFE) of 120 at 2mA collector current and 6V collector-emitter voltage. The KSC1815YTA specifies minimum hFE of 70 at the same conditions. The 2N6428 PBFREE specifies minimum hFE of 250 at 10mA collector current and 5V collector-emitter voltage. Circuit designs dependent on specific gain characteristics must account for these differences.

Q: Are all substitute parts RoHS compliant?

A: The KSC1815YTA and 2N6428 PBFREE are both ROHS3 compliant. The original KSC1815YBU does not specify RoHS status. Both substitute parts are REACH unaffected, matching the compliance profile of the original part.

Q: Can the 2N6428 PBFREE be used in all applications designed for the KSC1815YBU?

A: The 2N6428 PBFREE is electrically compatible with the KSC1815YBU for applications operating within the original part's specifications. The higher current rating (200mA versus 150mA), power dissipation (1.5W versus 400mW), and transition frequency (100MHz versus 80MHz) provide additional performance margin. However, the higher Vce saturation voltage (600mV versus 250mV) may affect switching speed in saturation-mode applications. Circuit validation is necessary for applications with tight saturation voltage requirements.

Q: What is the significance of the TO-92-3 package designation?

A: TO-92-3 is a three-lead through-hole package with a specific pin configuration. All three substitute parts use this package, ensuring mechanical and electrical compatibility with existing PCB layouts and socket configurations. The package supports through-hole soldering and is suitable for manual assembly and repair operations.

Q: Why is the KSC1815YBU classified as obsolete?

A: The KSC1815YBU is listed as obsolete by onsemi. The KSC1815YTA, manufactured by the same company, is the active replacement part with identical specifications. For new designs and production, the KSC1815YTA is the recommended choice to ensure long-term component availability and supply chain continuity.

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