2N6123 PBFREE Equivalent & Substitute Parts

Part Overview

The 2N6123 PBFREE is an NPN bipolar junction transistor manufactured by Central Semiconductor Corp, rated for 80V collector-emitter breakdown voltage and 4A maximum collector current in a TO-220-3 through-hole package. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement continuity. The part operates across a temperature range of -65°C to 150°C and delivers 40W maximum power dissipation with a 2.5MHz transition frequency.

Key Parameters

Parameter	Value	Unit
Transistor Type	NPN	—
Voltage - Collector Emitter Breakdown (Max)	80	V
Current - Collector (Ic) (Max)	4	A
Power - Max	40	W
Frequency - Transition	2.5	MHz
Operating Temperature Range	-65 to 150	°C
Mounting Type	Through Hole	—
Package / Case	TO-220-3	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution of the 2N6123 PBFREE is determined by strict alignment of the following electrical and mechanical parameters:

Critical Matching Parameters:

Transistor Type: NPN (all substitutes must be NPN)
Voltage - Collector Emitter Breakdown (Max): 80V (all substitutes rated at 80V)
Package / Case: TO-220-3 through-hole configuration (all substitutes use TO-220-3 or compatible TO-220 variants)
Operating Temperature Range: -65°C to 150°C (all substitutes support this range)
RoHS3 Compliance: Required for regulatory alignment

Allowable Parameter Variation:

Current - Collector (Ic) (Max): Substitutes may exceed 4A (higher current capability is acceptable for drop-in replacement)
Power - Max: Substitutes may differ from 40W (power rating variation is acceptable)
Frequency - Transition: Substitutes may differ from 2.5MHz (frequency variation is acceptable)
DC Current Gain (hFE): Substitutes may differ from 20 (gain variation is acceptable)

The three substitute parts listed below meet all critical matching parameters and are electrically and mechanically compatible with the 2N6123 PBFREE.

Parameter Comparison

Parameter	2N6123 PBFREE	2N6488G	KSD1408YTU	KSE44H11
Manufacturer	Central Semiconductor Corp	onsemi	Fairchild Semiconductor	onsemi
Transistor Type	NPN	NPN	NPN	NPN
Voltage - Collector Emitter Breakdown (Max)	80 V	80 V	80 V	80 V
Current - Collector (Ic) (Max)	4 A	15 A	4 A	10 A
Power - Max	40 W	1.8 W	25 W	1.67 W
Frequency - Transition	2.5 MHz	5 MHz	8 MHz	50 MHz
Operating Temperature Range	-65 to 150 °C	-65 to 150 °C	to 150 °C	to 150 °C
Package / Case	TO-220-3	TO-220-3	TO-220-3 Full Pack	TO-220-3
Product Status	Obsolete	Active	Active	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	Not specified	ROHS3 Compliant

Engineering Selection Recommendations

2N6488G (onsemi) is suitable for applications requiring higher collector current capacity (15A maximum) while maintaining the 80V voltage rating and TO-220-3 package. This part is active in production with ROHS3 compliance and identical operating temperature range. The increased current capability provides design margin for applications originally designed around the 2N6123 PBFREE 4A specification.

KSD1408YTU (Fairchild Semiconductor) matches the 4A collector current specification of the 2N6123 PBFREE and provides 25W power dissipation in a TO-220-3 full pack configuration. This part is active in production and maintains the 80V voltage rating and operating temperature range. RoHS compliance status is not specified in available documentation.

KSE44H11 (onsemi) provides 10A collector current capacity with 80V voltage rating in a TO-220-3 package. This part is active in production with ROHS3 compliance and identical operating temperature range. The higher transition frequency (50MHz) and increased current capability support applications requiring enhanced performance margins.

All three substitute parts are electrically and mechanically compatible with the 2N6123 PBFREE based on matching critical parameters: NPN type, 80V breakdown voltage, TO-220-3 package, and -65°C to 150°C operating temperature range.

Frequently Asked Questions (FAQ)

Q: Can the 2N6488G replace the 2N6123 PBFREE in all applications?

A: The 2N6488G is electrically and mechanically compatible as a substitute. It maintains the 80V voltage rating, NPN type, and TO-220-3 package. The higher 15A collector current rating does not prevent substitution in circuits designed for 4A operation. Verify that circuit design does not depend on the specific 2.5MHz transition frequency of the original part.

Q: What is the primary difference between KSD1408YTU and the other substitutes?

A: KSD1408YTU matches the 4A collector current specification of the 2N6123 PBFREE, making it the closest electrical equivalent. It is packaged as TO-220-3 full pack (bulk packaging) rather than tube packaging. All three substitutes maintain the critical 80V voltage rating and TO-220-3 through-hole configuration.

Q: Are all substitute parts RoHS3 compliant?

A: 2N6488G and KSE44H11 are explicitly ROHS3 compliant. KSD1408YTU RoHS compliance status is not specified in the provided documentation. Verify RoHS requirements for your specific application before final selection.

Q: Can I use KSE44H11 in place of 2N6123 PBFREE?

A: Yes. KSE44H11 is electrically and mechanically compatible. It provides 10A collector current (exceeding the 4A requirement), maintains 80V voltage rating, uses TO-220-3 package, and operates across -65°C to 150°C. The 50MHz transition frequency exceeds the original 2.5MHz specification.

Q: What packaging differences exist among the substitutes?

A: 2N6123 PBFREE and 2N6488G are supplied in tube packaging. KSD1408YTU is supplied in bulk packaging as TO-220-3 full pack. KSE44H11 is supplied in bulk packaging. All three use the same TO-220-3 through-hole footprint and are mechanically interchangeable.

Q: Is the 2N6123 PBFREE still available for procurement?

A: The 2N6123 PBFREE is classified as obsolete. However, 1599 pieces are reported in stock as new original inventory. For long-term design continuity, use one of the three active substitute parts: 2N6488G, KSD1408YTU, or KSE44H11.

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