KSA940 Equivalent & Substitute Parts

Part Overview

The KSA940 is a PNP Bipolar Junction Transistor (BJT) manufactured by onsemi, rated for 150 V collector-emitter breakdown voltage and 1.5 A maximum collector current. The device is packaged in a TO-220-3 through-hole configuration and is designed for general-purpose switching and amplification applications requiring 1.5 W power dissipation capability.

The KSA940 is classified as an obsolete product. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production requirements for applications utilizing this transistor.

Key Parameters

Parameter	Value	Unit
Transistor Type	PNP	—
Voltage - Collector Emitter Breakdown (Max)	150	V
Current - Collector (Ic) (Max)	1.5	A
Power - Max	1.5	W
Frequency - Transition	4	MHz
Mounting Type	Through Hole	—
Package / Case	TO-220-3	—
Operating Temperature (Max)	150	°C

Substitute Part Grouping Explanation

Substitute parts for the KSA940 are classified into two categories based on electrical and mechanical parameter alignment:

Direct Substitutes share identical electrical specifications and mechanical packaging. These parts satisfy all functional requirements of the original KSA940 without circuit modification.

Similar Substitutes maintain the same transistor type (PNP), voltage rating (150 V), and through-hole TO-220 package configuration, but feature enhanced current-handling capability, power dissipation, and frequency response. These parts are electrically compatible for applications where the KSA940 operates below its maximum ratings.

The critical parameters determining substitution eligibility are:

Transistor polarity (PNP)
Collector-emitter breakdown voltage (minimum 150 V)
Through-hole mounting configuration
TO-220 package family

Parameter Comparison

Parameter	KSA940	KSA940TU	MJE15031G
Manufacturer	onsemi	onsemi	onsemi
Transistor Type	PNP	PNP	PNP
Voltage - Collector Emitter Breakdown (Max)	150 V	150 V	150 V
Current - Collector (Ic) (Max)	1.5 A	1.5 A	8 A
Vce Saturation (Max) @ Ib, Ic	1.5V @ 50mA, 500mA	1.5V @ 50mA, 500mA	500mV @ 100mA, 1A
Current - Collector Cutoff (Max)	10µA	10µA	100µA
DC Current Gain (hFE) (Min) @ Ic, Vce	40 @ 500mA, 10V	40 @ 500mA, 10V	20 @ 4A, 2V
Power - Max	1.5 W	1.5 W	50 W
Frequency - Transition	4 MHz	4 MHz	30 MHz
Operating Temperature (Max)	150°C	150°C	150°C
Mounting Type	Through Hole	Through Hole	Through Hole
Package / Case	TO-220-3	TO-220-3	TO-220-3
Product Status	Obsolete	Active	Active
RoHS Status	Not specified	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

KSA940TU is the primary direct substitute for the KSA940. This part maintains identical electrical specifications and mechanical packaging while offering active product status and ROHS3 compliance. The KSA940TU is suitable for direct replacement in all applications where the KSA940 was originally specified. Inventory availability is significantly higher (35,250 units) compared to the original KSA940 (1,225 units).

MJE15031G is a similar substitute offering enhanced performance characteristics. This part maintains the 150 V voltage rating and through-hole TO-220 package configuration but provides increased current capacity (8 A versus 1.5 A), higher power dissipation (50 W versus 1.5 W), and improved frequency response (30 MHz versus 4 MHz). The MJE15031G is suitable for applications where the KSA940 operates below its maximum electrical ratings and where enhanced performance margins are beneficial. This part is also ROHS3 compliant and maintains active product status.

Both substitute parts are manufactured by onsemi, carry REACH Unaffected status, and are classified under identical ECCN and HTSUS codes as the original KSA940, ensuring regulatory and compliance consistency.

Frequently Asked Questions (FAQ)

Q: Can the KSA940TU be used as a direct replacement for the KSA940?

A: Yes. The KSA940TU is electrically and mechanically identical to the KSA940, with matching voltage ratings, current capacity, power dissipation, and frequency response. The primary difference is product status (active versus obsolete) and packaging format (tube versus unspecified). No circuit modifications are required.

Q: What are the advantages of using MJE15031G over KSA940TU?

A: The MJE15031G provides enhanced performance specifications including 5.3 times higher maximum collector current (8 A versus 1.5 A), 33 times higher power dissipation capability (50 W versus 1.5 W), and 7.5 times higher transition frequency (30 MHz versus 4 MHz). These enhancements provide greater design margin and performance headroom for applications requiring higher switching speeds or current handling.

Q: Are there packaging differences between the substitute parts?

A: All three parts utilize the TO-220-3 through-hole package configuration. The KSA940TU is supplied in tube packaging, while the MJE15031G is also supplied in tube packaging. The original KSA940 packaging format is not specified in the available data. Physical dimensions and pin configurations are identical across all three parts.

Q: Is the MJE15031G suitable for all KSA940 applications?

A: The MJE15031G is suitable for applications where the KSA940 operates below its maximum electrical ratings. The MJE15031G maintains the same 150 V voltage rating and PNP polarity, ensuring compatibility with existing circuit designs. However, the enhanced current and power specifications of the MJE15031G may result in different thermal characteristics and require verification of thermal management in the specific application context.

Q: What is the compliance status of the substitute parts?

A: Both KSA940TU and MJE15031G are ROHS3 compliant and carry REACH Unaffected status. Both parts are classified under EAR99 ECCN and identical HTSUS codes (8541.29.0095 for KSA940TU and 8541.29.0075 for MJE15031G), ensuring regulatory consistency with the original KSA940.

Q: Why is the KSA940 classified as obsolete?

A: The KSA940 is listed as an obsolete product by onsemi. The KSA940TU, which maintains identical specifications, is the active replacement part and should be used for new designs and ongoing production requirements.

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