KSC3503CS Equivalent & Substitute Parts

Part Overview

The KSC3503CS is a through-hole NPN bipolar junction transistor manufactured by onsemi, rated for 300 V collector-emitter breakdown voltage and 100 mA maximum collector current. This device is packaged in TO-126-3 configuration and is designed for general-purpose switching and amplification applications requiring moderate voltage and current ratings.

The KSC3503CS is classified as obsolete. Identifying equivalent and substitute parts is necessary to maintain design continuity and ensure component availability for production, repair, and maintenance applications.

Key Parameters

Parameter	Value	Unit
Transistor Type	NPN	—
Current - Collector (Ic) Max	100	mA
Voltage - Collector Emitter Breakdown (Max)	300	V
Vce Saturation (Max)	600	mV @ 2mA, 20mA
Current - Collector Cutoff (Max)	100	nA
DC Current Gain (hFE) Min	40	@ 10mA, 10V
Power - Max	7	W
Frequency - Transition	150	MHz
Operating Temperature Range	-55 to 150	°C
Mounting Type	Through Hole	—
Package / Case	TO-126-3	—

Substitute Part Grouping Explanation

Substitution of the KSC3503CS is determined by strict equivalence across the following electrical and mechanical parameters:

Transistor Type: NPN configuration
Current Rating: 100 mA maximum collector current
Voltage Rating: 300 V collector-emitter breakdown voltage
Saturation Characteristics: 600 mV Vce saturation at specified base and collector currents
Current Gain: Minimum 40 hFE at 10 mA collector current and 10 V Vce
Power Dissipation: 7 W maximum
Frequency Response: 150 MHz transition frequency
Temperature Range: -55°C to 150°C operating range
Package: TO-126-3 through-hole configuration

The KSC3503DSTU meets all electrical specifications and mechanical requirements for direct substitution. The primary distinction is product status and packaging format.

Parameter Comparison

Parameter	KSC3503CS	KSC3503DSTU	Match
Transistor Type	NPN	NPN	✓
Current - Collector (Ic) Max	100 mA	100 mA	✓
Voltage - Collector Emitter Breakdown (Max)	300 V	300 V	✓
Vce Saturation (Max)	600 mV @ 2mA, 20mA	600 mV @ 2mA, 20mA	✓
Current - Collector Cutoff (Max)	100 nA	100 nA	✓
DC Current Gain (hFE) Min	40 @ 10mA, 10V	40 @ 10mA, 10V	✓
Power - Max	7 W	7 W	✓
Frequency - Transition	150 MHz	150 MHz	✓
Operating Temperature Range	-55°C to 150°C	-55°C to 150°C	✓
Mounting Type	Through Hole	Through Hole	✓
Package / Case	TO-126-3	TO-126-3	✓
Product Status	Obsolete	Active	—
RoHS Status	Not specified	ROHS3 Compliant	—

Engineering Selection Recommendations

The KSC3503DSTU is the direct substitute for the obsolete KSC3503CS. All electrical parameters, mechanical specifications, and thermal characteristics are identical. The KSC3503DSTU is classified as an active product with current manufacturing support.

The KSC3503DSTU carries ROHS3 compliance certification, whereas the KSC3503CS compliance status is not specified. Both devices maintain REACH Unaffected status and EAR99 export classification.

For new designs and production applications, the KSC3503DSTU is the appropriate selection. For legacy system maintenance requiring the original KSC3503CS, the KSC3503DSTU provides full electrical and mechanical compatibility.

Frequently Asked Questions (FAQ)

Q: Can the KSC3503DSTU replace the KSC3503CS in existing designs?

A: Yes. The KSC3503DSTU is electrically and mechanically equivalent to the KSC3503CS across all specified parameters, including voltage rating, current rating, gain characteristics, frequency response, and temperature range. Both devices use the TO-126-3 through-hole package.

Q: What is the primary difference between these two parts?

A: The KSC3503CS is classified as obsolete, while the KSC3503DSTU is an active product with current manufacturing availability. The KSC3503DSTU also carries ROHS3 compliance certification. All electrical and mechanical specifications are identical.

Q: Are there any package or pinout differences?

A: No. Both the KSC3503CS and KSC3503DSTU use the TO-126-3 package configuration. Pinout and mechanical dimensions are identical, allowing direct board-level substitution.

Q: What are the critical parameters for substitution?

A: Substitution is valid when the following parameters match: NPN transistor type, 100 mA maximum collector current, 300 V collector-emitter breakdown voltage, 600 mV Vce saturation, 40 minimum hFE at specified conditions, 7 W power rating, 150 MHz transition frequency, -55°C to 150°C operating range, and TO-126-3 through-hole package.

Q: Is the KSC3503DSTU suitable for high-temperature applications?

A: Yes. The KSC3503DSTU operates across the full temperature range of -55°C to 150°C, matching the KSC3503CS specification. Thermal design considerations remain unchanged between the two devices.

Q: What compliance certifications apply to the KSC3503DSTU?

A: The KSC3503DSTU is ROHS3 compliant and REACH unaffected. It carries EAR99 export classification. Compliance documentation should be verified with the manufacturer for specific regulatory requirements.

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