KSC1845UBU Equivalent & Substitute Parts

Part Overview

The KSC1845UBU is a Bipolar (BJT) NPN transistor manufactured by onsemi, rated for 120 V collector-emitter breakdown voltage and 50 mA maximum collector current. This device is packaged in a TO-92-3 through-hole configuration and is designed for general-purpose switching and amplification applications requiring 500 mW power dissipation capability.

The KSC1845UBU is classified as an obsolete product. Locating equivalent or substitute components is necessary to support ongoing maintenance, repair, and production requirements for legacy equipment and systems utilizing this transistor.

Substiute Parts

KSC1845UBU

onsemiIn Stock: 907KSC1845UBU Datasheet

Current PartRFQ

KSC1845FTA

onsemiIn Stock: 31820KSC1845FTA Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the KSC1845UBU is determined by electrical and mechanical parameter equivalence. The following criteria establish valid substitution:

Electrical Parameters (Must Match):

• Transistor Type: NPN
• Voltage - Collector Emitter Breakdown (Max): 120 V
• Current - Collector (Ic) (Max): 50 mA
• Power - Max: 500 mW
• Frequency - Transition: 110 MHz
• Operating Temperature (TJ): 150 °C

Mechanical Parameters (Must Match):

• Mounting Type: Through Hole
• Package / Case: TO-92-3 (TO-226AA)

The KSC1845FTA meets all electrical and mechanical substitution criteria. Both devices share the same base product number (KSC1845) and are manufactured by onsemi, confirming design compatibility at the functional level.

Parameter Comparison

Engineering Selection Recommendations

The KSC1845FTA is a direct electrical and mechanical substitute for the KSC1845UBU. Both devices are manufactured by onsemi and share identical electrical ratings for voltage, current, power dissipation, and frequency response. The physical package and through-hole mounting configuration are equivalent.

Product Status Consideration: The KSC1845UBU is classified as obsolete, while the KSC1845FTA is active. The KSC1845FTA is the current production equivalent and is available in higher inventory quantities (31,783 pieces versus 877 pieces for the obsolete variant).

Compliance Consideration: The KSC1845FTA carries ROHS3 compliance certification, whereas compliance information for the KSC1845UBU is not provided in the available data. Both devices are REACH Unaffected and carry the same ECCN (EAR99) and HTSUS (8541.21.0075) classifications.

DC Current Gain Variation: The KSC1845FTA specifies a minimum DC current gain (hFE) of 300 @ 1mA, 6V, compared to 600 @ 1mA, 6V for the KSC1845UBU. This represents a lower gain specification for the substitute part. Circuit designs dependent on specific hFE values require evaluation against the KSC1845FTA specification.

Packaging Difference: The KSC1845FTA is supplied in Cut Tape (CT) packaging, whereas the KSC1845UBU packaging type is not specified. Both devices use the TO-92-3 package with formed leads suitable for through-hole assembly.

Frequently Asked Questions (FAQ)

Q: Can the KSC1845FTA directly replace the KSC1845UBU in existing circuit designs?

A: The KSC1845FTA meets all primary electrical and mechanical substitution criteria. Both devices share identical voltage ratings (120 V), current ratings (50 mA), power dissipation (500 mW), and frequency response (110 MHz). The physical TO-92-3 package and through-hole mounting are equivalent. However, the DC current gain (hFE) specification differs between the two parts. Circuits designed with specific gain requirements must be evaluated against the KSC1845FTA specification of 300 @ 1mA, 6V.

Q: What is the difference between the KSC1845UBU and KSC1845FTA packaging?

A: Both devices use the TO-92-3 (TO-226AA) through-hole package. The KSC1845FTA is supplied in Cut Tape (CT) format, while the KSC1845UBU packaging format is not specified in the available data. The physical component dimensions and lead configuration are equivalent for circuit board assembly purposes.

Q: Why is the KSC1845UBU listed as obsolete?

A: The KSC1845UBU is classified as an obsolete product by onsemi. The KSC1845FTA is the active production equivalent. For new designs and ongoing production support, the KSC1845FTA is the recommended selection.

Q: Are there compliance differences between these two parts?

A: The KSC1845FTA carries ROHS3 compliance certification. Compliance information for the KSC1845UBU is not provided in the available technical data. Both devices are REACH Unaffected and share identical ECCN (EAR99) and HTSUS (8541.21.0075) classifications.

Q: What is the significance of the DC current gain (hFE) difference?

A: The KSC1845UBU specifies a minimum hFE of 600 @ 1mA, 6V, while the KSC1845FTA specifies 300 @ 1mA, 6V. This represents a 50% reduction in minimum gain specification. Circuits utilizing current-driven switching or amplification stages with tight gain tolerances require circuit analysis to confirm acceptable operation with the lower hFE value of the substitute part.

Q: Is the KSC1845FTA available in higher quantities than the KSC1845UBU?

A: Yes. The KSC1845FTA has 31,783 pieces in stock, compared to 877 pieces for the obsolete KSC1845UBU. The active production status of the KSC1845FTA ensures ongoing availability for production and maintenance applications.