KSC1674OTA Equivalent & Substitute Parts

Part Overview

The KSC1674OTA is an RF transistor NPN manufactured by onsemi, rated for 20V collector-emitter breakdown voltage with a transition frequency of 600MHz and maximum power dissipation of 250mW. This component is packaged in a through-hole TO-92-3 configuration and is classified as obsolete. Due to its obsolete status, equivalent and substitute parts are necessary for ongoing design requirements, system maintenance, and production continuity. Substitute parts listed below provide functional alternatives with varying electrical specifications and packaging options suitable for RF applications.

Key Parameters

Parameter	KSC1674OTA	Unit
Transistor Type	NPN	-
Voltage - Collector Emitter Breakdown (Max)	20V	V
Frequency - Transition	600MHz	MHz
Noise Figure (Typ @ f)	3dB ~ 5dB @ 100MHz	dB
Power - Max	250mW	mW
DC Current Gain (hFE) (Min) @ Ic, Vce	70 @ 1mA, 6V	-
Current - Collector (Ic) (Max)	20mA	mA
Operating Temperature (TJ)	150°C	°C
Mounting Type	Through Hole	-
Package / Case	TO-226-3, TO-92-3	-
Product Status	Obsolete	-

Substitute Part Grouping Explanation

Substitution of the KSC1674OTA is determined by the following electrical and mechanical parameters: transistor type (NPN), voltage rating, frequency capability, power dissipation, current handling, and operating temperature. The substitute parts are grouped into two categories based on application suitability:

Category 1: Low-Power RF Transistors (Surface Mount) These substitutes maintain NPN type and operate within comparable frequency ranges (600MHz to 25GHz) with reduced power dissipation (100mW to 230mW) and lower voltage ratings (3.5V to 6V). These parts are suitable for applications where the original through-hole package can be replaced with surface-mount technology.

Category 2: High-Power RF Transistors (Chassis Mount) These substitutes provide significantly higher power handling (350W to 550W) and higher voltage ratings (65V to 80V) with chassis-mount packaging. These parts are suitable for applications requiring substantially greater power dissipation than the original part.

Key Parameters for Substitution:

Transistor Type: NPN (all substitutes match)
Operating Temperature: 150°C or higher (all substitutes match or exceed)
Voltage Rating: Must meet or exceed application requirements
Frequency Capability: Must meet or exceed application requirements
Power Dissipation: Must meet or exceed application requirements
Current Handling: Must meet or exceed application requirements

Parameter Comparison

Part Number	Manufacturer	Transistor Type	Voltage (Max)	Frequency	Power (Max)	Ic (Max)	Operating Temp	Mounting Type	Package	Product Status
KSC1674OTA	onsemi	NPN	20V	600MHz	250mW	20mA	150°C	Through Hole	TO-92-3	Obsolete
2SC4713KT146S	Rohm Semiconductor	NPN	6V	800MHz	200mW	50mA	150°C	Surface Mount	SOT-23-3	Active
BFP420H6433XTMA1	Infineon Technologies	NPN	5V	25GHz	160mW	35mA	150°C	Surface Mount	SOT-343	Active
BFP460H6327XTSA1	Infineon Technologies	NPN	5.8V	22GHz	230mW	70mA	150°C	Surface Mount	SOT-343	Active
BFP520FH6327XTSA1	Infineon Technologies	NPN	3.5V	45GHz	100mW	40mA	150°C	Surface Mount	4-TSFP	Active
BFR380L3E6327XTMA1	Infineon Technologies	NPN	9V	14GHz	380mW	80mA	150°C	Surface Mount	SOT-883	Active
MAPRST0912-350	MACOM Technology Solutions	NPN	65V	1.215GHz	350W	32.5A	200°C	Chassis Mount	Chassis Mount	Active
PH1090-550S	MACOM Technology Solutions	Chassis Mount	80V	-	550W	28A	200°C	Chassis Mount	Chassis Mount	Active

Engineering Selection Recommendations

For Low-Power RF Applications (Replacement in Signal-Level Circuits):

The 2SC4713KT146S, BFP420H6433XTMA1, BFP460H6327XTSA1, and BFP520FH6327XTSA1 are active products suitable for replacing the obsolete KSC1674OTA in applications where the original through-hole package can be transitioned to surface-mount technology. These parts maintain the 150°C operating temperature specification and provide NPN transistor functionality. The 2SC4713KT146S offers the closest voltage rating (6V) to the original 20V specification among low-power options, though it requires circuit redesign for lower voltage operation. The BFP460H6327XTSA1 provides the highest power dissipation (230mW) among surface-mount options, closest to the original 250mW rating. All low-power substitutes carry ROHS3 compliance and REACH Unaffected status.

For High-Power RF Applications (Replacement in Power Amplifier Circuits):

The MAPRST0912-350 and PH1090-550S are active products designed for high-power RF applications. These parts provide substantially higher power handling and voltage ratings compared to the original KSC1674OTA. The MAPRST0912-350 operates at 65V with 350W maximum power dissipation and 1.215GHz frequency capability. The PH1090-550S operates at 80V with 550W maximum power dissipation. Both parts feature 200°C operating temperature capability and carry ROHS3 compliance and REACH Unaffected status. These parts are suitable only for applications requiring power levels significantly exceeding the original 250mW specification.

For Intermediate Power Applications:

The BFR380L3E6327XTMA1 provides intermediate power handling (380mW) with 9V voltage rating and 14GHz frequency capability, positioned between low-power and high-power categories. This part is an active product with ROHS3 compliance and REACH Unaffected status.

Frequently Asked Questions (FAQ)

Q: Can the KSC1674OTA be directly replaced with the 2SC4713KT146S?

A: Direct replacement requires circuit redesign. The 2SC4713KT146S operates at 6V maximum collector-emitter breakdown voltage compared to the original 20V rating. The part is also surface-mount (SOT-23-3) rather than through-hole (TO-92-3). Electrical circuit parameters must be recalculated for the lower voltage rating and different current characteristics.

Q: What is the primary difference between the low-power and high-power substitute categories?

A: Low-power substitutes (2SC4713KT146S, BFP420H6433XTMA1, BFP460H6327XTSA1, BFP520FH6327XTSA1, BFR380L3E6327XTMA1) are surface-mount devices with power dissipation ranging from 100mW to 380mW, suitable for signal-level RF applications. High-power substitutes (MAPRST0912-350, PH1090-550S) are chassis-mount devices with power dissipation of 350W to 550W, suitable for power amplifier applications. Selection depends on application power requirements.

Q: Are all substitute parts RoHS compliant?

A: All substitute parts listed carry ROHS3 compliance status. The original KSC1674OTA does not specify RoHS status in the provided data.

Q: What packaging considerations apply when selecting a substitute?

A: The original KSC1674OTA uses through-hole TO-92-3 packaging. Low-power substitutes use surface-mount packages (SOT-23-3, SOT-343, 4-TSFP, SOT-883), requiring PCB redesign and different assembly processes. High-power substitutes use chassis-mount packaging, requiring mechanical mounting modifications. Package selection must align with PCB design and assembly capabilities.

Q: Which substitute provides the closest electrical match to the original KSC1674OTA?

A: No single substitute provides a complete electrical match across all parameters. The BFP460H6327XTSA1 provides the closest power dissipation match (230mW versus 250mW original) and operates at 150°C like the original. However, it operates at 5.8V versus the original 20V and uses surface-mount SOT-343 packaging. Application-specific requirements determine the most suitable substitute.

Q: Can the MAPRST0912-350 or PH1090-550S be used in low-power applications?

A: These high-power chassis-mount parts are designed for applications requiring their specified power levels and voltage ratings. Using them in low-power applications would result in inefficient design and unnecessary cost. Low-power substitutes should be selected for signal-level applications.

Q: What is the operating temperature range for all substitute parts?

A: All low-power substitutes operate at 150°C maximum junction temperature, matching the original KSC1674OTA. High-power substitutes (MAPRST0912-350, PH1090-550S) operate at 200°C maximum junction temperature, providing higher thermal capability.

Q: Are all substitute parts currently in active production?

A: Yes, all substitute parts listed carry Active product status. The original KSC1674OTA is classified as Obsolete, making active substitutes necessary for new designs and ongoing production.

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