KTC3198-Y B1G Equivalent & Substitute Parts

Part Overview

The KTC3198-Y B1G is an NPN bipolar junction transistor manufactured by Taiwan Semiconductor Corporation, designed for general-purpose switching and amplification applications. This device features a 50 V collector-emitter breakdown voltage, 150 mA maximum collector current, and 500 mW power dissipation in a through-hole TO-92 package.

The KTC3198-Y B1G is classified as obsolete. Locating equivalent substitute parts is necessary to support ongoing production requirements, maintenance operations, and system redesigns where this component is specified in existing designs.

Substiute Parts

KTC3198-Y B1G

Taiwan Semiconductor CorporationIn Stock: 783KTC3198-Y B1G Datasheet

Current PartRFQ

KSC945YBU

Fairchild SemiconductorIn Stock: 19512KSC945YBU Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the KTC3198-Y B1G is determined by electrical and mechanical compatibility across the following critical parameters:

Electrical Compatibility Criteria:

• Transistor type must be NPN
• Voltage - Collector Emitter Breakdown (Max) must be ≥ 50 V
• Current - Collector (Ic) (Max) must be ≥ 150 mA
• Vce Saturation characteristics must support the same switching performance envelope
• DC Current Gain (hFE) must be sufficient for the intended bias conditions
• Current - Collector Cutoff (Max) must be ≤ 100 nA

Mechanical Compatibility Criteria:

• Mounting type must be Through Hole
• Package must be TO-92-3 (TO-226AA)
• Pin configuration must be compatible with existing PCB layouts

The KSC945YBU meets all electrical and mechanical substitution criteria for the KTC3198-Y B1G. Both devices share identical voltage and current ratings, compatible saturation characteristics, and identical package specifications.

Parameter Comparison

Engineering Selection Recommendations

KSC945YBU as Primary Substitute:

The KSC945YBU is an active product manufactured by Fairchild Semiconductor and serves as a direct electrical and mechanical substitute for the obsolete KTC3198-Y B1G. Both devices are classified as NPN bipolar junction transistors with identical voltage and current ratings, compatible saturation characteristics, and identical TO-92-3 package specifications.

The KSC945YBU provides superior performance characteristics in several areas: DC current gain is higher (120 @ 1 mA, 6 V versus 70 @ 2 mA, 6 V), and transition frequency is significantly higher (300 MHz versus 80 MHz). These improvements enhance switching speed and reduce base drive requirements in typical applications.

One design consideration exists: the KSC945YBU has a maximum power dissipation rating of 250 mW compared to the KTC3198-Y B1G at 500 mW. Applications requiring sustained power dissipation above 250 mW require thermal analysis and potential circuit derating to ensure reliable operation within the substitute device's power envelope.

Both devices are RoHS compliant and carry identical ECCN and HTSUS classifications, supporting regulatory and supply chain continuity.

Frequently Asked Questions (FAQ)

Q: Can the KSC945YBU directly replace the KTC3198-Y B1G without circuit modification?

A: The KSC945YBU is mechanically and electrically compatible with the KTC3198-Y B1G for most general-purpose switching and amplification applications. Both devices share identical voltage ratings (50 V), current ratings (150 mA), package type (TO-92-3), and pin configuration. No circuit modification is required for pin-compatible substitution. However, applications operating near the 500 mW power dissipation limit of the original device require evaluation against the 250 mW maximum rating of the substitute.

Q: What is the difference in saturation voltage between these devices?

A: The KTC3198-Y B1G specifies a maximum Vce saturation of 250 mV at 10 mA base current and 100 mA collector current. The KSC945YBU specifies 300 mV under identical test conditions. This 50 mV difference is within acceptable tolerances for most switching applications and does not prevent substitution. Applications with strict saturation voltage requirements should evaluate the impact on circuit performance.

Q: Why does the KSC945YBU have a lower power rating than the KTC3198-Y B1G?

A: The KSC945YBU is rated for 250 mW maximum power dissipation, while the KTC3198-Y B1G is rated for 500 mW. This difference reflects the thermal design and package characteristics of each device. Both use identical TO-92-3 packages, but the KSC945YBU's lower power rating requires thermal management consideration in high-dissipation applications. Circuit design should ensure that sustained power dissipation does not exceed 250 mW.

Q: Are there any compliance or regulatory differences between these devices?

A: Both the KTC3198-Y B1G and KSC945YBU carry identical ECCN (EAR99) and HTSUS (8541.21.0095) classifications. Both are RoHS compliant. No regulatory or compliance barriers exist to substitution.

Q: What is the advantage of the higher transition frequency in the KSC945YBU?

A: The KSC945YBU operates at 300 MHz transition frequency compared to 80 MHz for the KTC3198-Y B1G. This higher frequency capability enables faster switching performance and supports applications requiring higher-speed signal processing. For applications operating below 80 MHz, this performance advantage is not utilized. For applications requiring switching speeds above 80 MHz, the KSC945YBU provides enhanced performance margin.

Q: Can I use the KSC945YBU in applications where the KTC3198-Y B1G was originally specified?

A: The KSC945YBU is suitable for applications where the KTC3198-Y B1G was originally specified, provided that power dissipation does not exceed 250 mW in sustained operation. The higher DC current gain and transition frequency of the KSC945YBU are compatible with or beneficial to most circuit designs. Verify that your specific application does not require the full 500 mW power capability of the original device.