KSC2690YSTU Equivalent & Substitute Parts

Part Overview

The KSC2690YSTU is an NPN bipolar junction transistor manufactured by onsemi, rated for 120 V collector-emitter breakdown voltage and 1.2 A maximum collector current. This device is packaged in TO-126-3 through-hole configuration and is classified as obsolete. The KSC2690YSTU has been superseded by active product variants within the KSC2690 series and alternative manufacturers' offerings. Identifying equivalent and substitute parts is necessary to maintain design continuity and ensure component availability for new production and repair applications.

Key Parameters

Parameter	Value	Unit
Transistor Type	NPN	—
Voltage - Collector Emitter Breakdown (Max)	120	V
Current - Collector (Ic) (Max)	1.2	A
Power - Max	1.2	W
Frequency - Transition	155	MHz
Vce Saturation (Max) @ Ib, Ic	700mV @ 200mA, 1A	—
DC Current Gain (hFE) (Min) @ Ic, Vce	160 @ 300mA, 5V	—
Operating Temperature (TJ)	150	°C
Mounting Type	Through Hole	—
Package / Case	TO-126-3	—

Substitute Part Grouping Explanation

Substitution of the KSC2690YSTU is determined by electrical and mechanical compatibility across the following critical parameters:

Primary Substitution Criteria:

Transistor Type: NPN configuration required
Mounting Type: Through Hole required
Package / Case: TO-126-3 compatible required
Voltage - Collector Emitter Breakdown (Max): Equal to or greater than 120 V
Current - Collector (Ic) (Max): Equal to or greater than 1.2 A
Power - Max: Equal to or greater than 1.2 W
Vce Saturation (Max): Equal to or less than 700mV @ 200mA, 1A
DC Current Gain (hFE) (Min): Equal to or greater than 160 @ 300mA, 5V

Secondary Compatibility Factors:

Frequency - Transition: Equal to or greater than 155 MHz
Operating Temperature: Equal to or greater than 150°C (TJ)

Parts meeting all primary criteria are classified as direct substitutes. Parts meeting primary electrical criteria but with different secondary parameters are classified as functional alternatives with application-dependent suitability.

Parameter Comparison

Parameter	KSC2690YSTU (Main)	KSC2690AYSTU	KSC2690AYS	MJE340
Manufacturer	onsemi	onsemi	onsemi	NTE Electronics, Inc
Transistor Type	NPN	NPN	NPN	NPN
Voltage - Collector Emitter Breakdown (Max)	120 V	160 V	160 V	300 V
Current - Collector (Ic) (Max)	1.2 A	1.2 A	1.2 A	500 mA
Power - Max	1.2 W	1.2 W	1.2 W	20 W
Frequency - Transition	155 MHz	155 MHz	155 MHz	—
Vce Saturation (Max) @ Ib, Ic	700mV @ 200mA, 1A	700mV @ 200mA, 1A	700mV @ 200mA, 1A	—
DC Current Gain (hFE) (Min) @ Ic, Vce	160 @ 300mA, 5V	160 @ 300mA, 5V	35 @ 5mA, 5V	30 @ 50mA, 10V
Current - Collector Cutoff (Max)	1µA (ICBO)	1µA (ICBO)	1µA (ICBO)	—
Operating Temperature (TJ)	150°C	150°C	150°C	—
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole
Package / Case	TO-126-3	TO-126-3	TO-126-3	TO-126
Product Status	Obsolete	Active	Active	Active
RoHS Status	—	ROHS3 Compliant	ROHS3 Compliant	RoHS non-compliant

Engineering Selection Recommendations

Direct Substitutes (Preferred):

KSC2690AYSTU and KSC2690AYS are direct substitutes for the KSC2690YSTU. Both parts are manufactured by onsemi, share identical electrical specifications including voltage rating (160 V), collector current (1.2 A), power dissipation (1.2 W), transition frequency (155 MHz), saturation voltage, and DC current gain. Both are packaged in TO-126-3 through-hole configuration. KSC2690AYSTU is available in tube packaging with 35,785 units in stock and holds active product status with ROHS3 compliance. KSC2690AYS is available in bulk packaging with 1,350 units in stock and also holds active product status with ROHS3 compliance. The higher voltage rating (160 V versus 120 V) of these substitutes provides enhanced design margin without compromising performance in applications rated for 120 V operation.

Functional Alternative:

MJE340 manufactured by NTE Electronics, Inc is a functional alternative with significant parameter differences. This device features a higher voltage rating (300 V), lower maximum collector current (500 mA), and substantially higher power dissipation capability (20 W). The MJE340 does not meet the primary substitution criterion of 1.2 A collector current and is therefore unsuitable for applications requiring the full 1.2 A rating of the KSC2690YSTU. The MJE340 is RoHS non-compliant, which may restrict its use in regulated applications. This part is listed as a functional alternative only for applications with reduced current requirements and is not recommended as a direct replacement.

Frequently Asked Questions (FAQ)

Q: Can KSC2690AYSTU be used as a direct replacement for KSC2690YSTU?

A: Yes. KSC2690AYSTU is a direct substitute. Both devices are NPN transistors with identical electrical specifications including 1.2 A collector current, 1.2 W power dissipation, 155 MHz transition frequency, and matching saturation voltage and DC current gain characteristics. The KSC2690AYSTU features a higher voltage rating (160 V versus 120 V), which provides additional design margin. Both use TO-126-3 through-hole packaging. KSC2690AYSTU is currently in active production status with ROHS3 compliance.

Q: What is the difference between KSC2690AYSTU and KSC2690AYS?

A: KSC2690AYSTU and KSC2690AYS are electrically identical NPN transistors with the same electrical specifications. The primary difference is packaging format: KSC2690AYSTU is supplied in tube packaging, while KSC2690AYS is supplied in bulk packaging. Both are manufactured by onsemi, hold active product status, and are ROHS3 compliant. Selection between these two variants depends on procurement and assembly requirements rather than electrical performance.

Q: Is MJE340 a suitable replacement for KSC2690YSTU?

A: MJE340 is not a suitable direct replacement. While both are NPN through-hole transistors in TO-126 packaging, the MJE340 has a maximum collector current of 500 mA, which is insufficient for applications requiring the 1.2 A rating of the KSC2690YSTU. The MJE340 is classified as a functional alternative only for applications with reduced current requirements below 500 mA. Additionally, MJE340 is RoHS non-compliant, which may restrict its use in regulated applications.

Q: Why is the KSC2690YSTU listed as obsolete?

A: The KSC2690YSTU is classified as obsolete by the manufacturer. However, direct substitutes in the KSC2690 series (KSC2690AYSTU and KSC2690AYS) are currently in active production and provide identical electrical performance with enhanced voltage ratings. These active variants are recommended for new designs and production applications.

Q: Are there any compliance differences between the substitute parts?

A: Yes. KSC2690AYSTU and KSC2690AYS are both ROHS3 compliant, while MJE340 is RoHS non-compliant. For applications subject to RoHS regulations, only KSC2690AYSTU or KSC2690AYS are acceptable substitutes. All three parts are REACH unaffected and classified under ECCN EAR99.

Q: Can these transistors be used interchangeably in existing circuit designs?

A: KSC2690AYSTU and KSC2690AYS can be used interchangeably with KSC2690YSTU in existing designs without circuit modification, provided the application does not depend on the specific 120 V voltage rating. The higher 160 V rating of the substitutes is backward compatible with 120 V designs. MJE340 requires circuit evaluation due to its lower current rating and is not recommended for direct interchange without design review.

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