KSD73Y Equivalent & Substitute Parts

Part Overview

The KSD73Y is an NPN bipolar junction transistor manufactured by onsemi, rated for 60V collector-emitter breakdown voltage and 5A maximum collector current in a TO-220-3 through-hole package. This device is classified as obsolete, making identification of functionally equivalent alternatives necessary for ongoing design support and procurement continuity. The KSD73Y delivers 30W maximum power dissipation with a 20MHz transition frequency, suitable for general-purpose switching and amplification applications requiring moderate voltage and current ratings.

Key Parameters

Parameter	Value	Unit
Transistor Type	NPN	—
Voltage - Collector Emitter Breakdown (Max)	60	V
Current - Collector (Ic) (Max)	5	A
Power - Max	30	W
Vce Saturation (Max)	2	V @ 500mA, 5A
DC Current Gain (hFE) (Min)	120	@ 1A, 10V
Frequency - Transition	20	MHz
Operating Temperature (TJ)	150	°C
Package / Case	TO-220-3	—
Mounting Type	Through Hole	—

Substitute Part Grouping Explanation

Substitution of the KSD73Y is determined by electrical and mechanical compatibility within the following criteria:

Mandatory Compatibility Parameters:

Transistor polarity: NPN
Package type: TO-220-3 through-hole
Collector-emitter breakdown voltage: equal to or greater than 60V
Maximum collector current: equal to or greater than 5A
Maximum power dissipation: equal to or greater than 30W

The TIP41C meets these substitution criteria. It provides higher voltage rating (100V), higher current capability (6A), and maintains the same TO-220-3 package configuration. The TIP41C is classified as active product status, ensuring continued availability and supply chain support.

Parameter Comparison

Parameter	KSD73Y (Main Part)	TIP41C (Substitute)	Unit
Manufacturer	onsemi	NTE Electronics, Inc	—
Product Status	Obsolete	Active	—
Transistor Type	NPN	NPN	—
Voltage - Collector Emitter Breakdown (Max)	60	100	V
Current - Collector (Ic) (Max)	5	6	A
Vce Saturation (Max)	2	1.5	V
DC Current Gain (hFE) (Min)	120	15	—
Power - Max	30	2	W
Frequency - Transition	20	3	MHz
Operating Temperature (TJ)	150	150	°C
Package / Case	TO-220-3	TO-220-3	—
Mounting Type	Through Hole	Through Hole	—

Engineering Selection Recommendations

The TIP41C serves as a direct substitute for the KSD73Y based on the following factors:

Product Status: The KSD73Y is obsolete, while the TIP41C is active. Active product status ensures long-term availability, supply chain stability, and manufacturer support.

Electrical Compatibility: The TIP41C exceeds the minimum electrical requirements of the KSD73Y. The higher collector-emitter breakdown voltage (100V versus 60V) and increased collector current rating (6A versus 5A) provide design margin for applications originally specified for the KSD73Y.

Package Compatibility: Both devices use identical TO-220-3 through-hole packaging, enabling direct mechanical substitution without PCB redesign or thermal management modifications.

Compliance: The TIP41C carries RoHS3 compliance certification, meeting current regulatory requirements for electronic component procurement.

Design Considerations: Applications requiring the full 30W power dissipation of the KSD73Y should account for the TIP41C's 2W maximum power rating. The TIP41C's lower transition frequency (3MHz versus 20MHz) and reduced DC current gain (15 versus 120) require circuit-level evaluation for high-frequency or high-gain applications.

Frequently Asked Questions (FAQ)

Q: Can the TIP41C directly replace the KSD73Y in all applications?

A: The TIP41C meets the mandatory electrical and mechanical substitution criteria (NPN polarity, TO-220-3 package, voltage and current ratings). However, applications dependent on the KSD73Y's 30W power dissipation or 20MHz transition frequency require circuit analysis to confirm compatibility with the TIP41C's lower ratings.

Q: What are the key differences between these devices?

A: The TIP41C provides higher voltage rating (100V) and current capability (6A) compared to the KSD73Y (60V, 5A). The KSD73Y offers higher power dissipation (30W) and transition frequency (20MHz). Both share identical TO-220-3 packaging and 150°C maximum junction temperature.

Q: Is the TO-220-3 package identical between both parts?

A: Yes. Both the KSD73Y and TIP41C use TO-220-3 through-hole packages with identical pin configurations and mechanical dimensions, enabling direct PCB substitution without layout modifications.

Q: Why is the TIP41C recommended over the KSD73Y?

A: The TIP41C is classified as active product status, ensuring continued manufacturing and supply availability. The KSD73Y is obsolete, presenting procurement and long-term support risks.

Q: Are there compliance or regulatory differences?

A: The TIP41C carries RoHS3 compliance certification. The KSD73Y is listed as REACH Unaffected. Current procurement standards favor active, RoHS-compliant components for new designs and legacy system support.

Q: What applications are suitable for the TIP41C as a KSD73Y substitute?

A: The TIP41C is suitable for general-purpose switching and amplification applications operating below 2W power dissipation and 3MHz frequency. Applications requiring the full 30W power rating or 20MHz bandwidth require alternative component selection or circuit redesign.

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