2SB861-B-BP Equivalent & Substitute Parts

Part Overview

The 2SB861-B-BP is a PNP bipolar junction transistor manufactured by Micro Commercial Co, designed for general-purpose switching and amplification applications. This component features a 150 V collector-emitter breakdown voltage rating and a maximum collector current of 2 A, housed in a TO-220AB through-hole package. The device is classified as obsolete, necessitating identification of functionally equivalent alternatives for ongoing design support and production requirements. Substitute parts must maintain electrical compatibility across critical parameters including voltage ratings, current capacity, and thermal characteristics.

Key Parameters

Parameter	Value	Unit
Transistor Type	PNP	—
Current - Collector (Ic) (Max)	2	A
Voltage - Collector Emitter Breakdown (Max)	150	V
Power - Max	1.8	W
Operating Temperature Range	−55 to 150	°C
Mounting Type	Through Hole	—
Package / Case	TO-220-3	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution of the 2SB861-B-BP is determined by strict equivalence across the following critical electrical and mechanical parameters:

Mandatory Matching Criteria:

Transistor polarity: PNP configuration
Collector current rating: 2 A maximum
Collector-emitter breakdown voltage: 150 V minimum
Package type: TO-220-3 through-hole configuration
RoHS compliance: ROHS3 Compliant

Allowable Parameter Variations: Substitute parts may exceed the maximum power dissipation rating, DC current gain (hFE), transition frequency, and collector cutoff current (ICBO) without compromising functional compatibility. These parameters represent performance enhancements that do not degrade circuit operation. Vce saturation characteristics may vary within acceptable limits for switching applications.

The KSB546YTU meets all mandatory matching criteria and is therefore qualified as a direct substitute for the 2SB861-B-BP.

Parameter Comparison

Parameter	2SB861-B-BP	KSB546YTU	Unit
Manufacturer	Micro Commercial Co	onsemi	—
Transistor Type	PNP	PNP	—
Current - Collector (Ic) (Max)	2	2	A
Voltage - Collector Emitter Breakdown (Max)	150	150	V
Vce Saturation (Max) @ Ib, Ic	3 V @ 50 mA, 500 mA	1 V @ 50 mA, 500 mA	V
Current - Collector Cutoff (Max)	1 µA	50 µA	µA
DC Current Gain (hFE) (Min)	60 @ 50 mA, 4 V	120 @ 400 mA, 10 V	—
Power - Max	1.8	25	W
Frequency - Transition	—	5	MHz
Operating Temperature (TJ)	−55 to 150	150	°C
Mounting Type	Through Hole	Through Hole	—
Package / Case	TO-220-3	TO-220-3	—
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	—
Product Status	Obsolete	Last Time Buy	—

Engineering Selection Recommendations

The KSB546YTU is a qualified substitute for the 2SB861-B-BP based on electrical and mechanical parameter equivalence. Both devices are ROHS3 compliant and housed in identical TO-220-3 through-hole packages, ensuring direct mechanical compatibility in existing PCB layouts.

The KSB546YTU exhibits superior performance characteristics, including higher maximum power dissipation (25 W versus 1.8 W), improved DC current gain (120 versus 60), and defined transition frequency (5 MHz). These enhancements provide additional design margin without introducing compatibility issues.

The KSB546YTU carries a Last Time Buy product status, indicating limited future availability. Procurement planning should account for this status when establishing long-term supply strategies.

Both devices operate within overlapping temperature ranges, with the KSB546YTU specified to 150°C maximum junction temperature. The 2SB861-B-BP supports operation from −55°C to 150°C. Applications requiring operation below 0°C require verification of the KSB546YTU's lower temperature limit through the manufacturer's detailed datasheet.

Frequently Asked Questions (FAQ)

Q: Can the KSB546YTU directly replace the 2SB861-B-BP in existing designs?

A: Yes. Both devices are PNP transistors with identical 2 A collector current and 150 V breakdown voltage ratings, housed in TO-220-3 packages. Pin configuration and mechanical dimensions are compatible, enabling direct substitution without PCB modification.

Q: What are the key differences between these two parts?

A: The KSB546YTU provides higher power dissipation capability (25 W versus 1.8 W), higher DC current gain (120 versus 60), and specified transition frequency (5 MHz). Vce saturation is lower on the KSB546YTU (1 V versus 3 V), indicating improved switching performance. These differences represent performance enhancements rather than incompatibilities.

Q: Are there packaging differences between the 2SB861-B-BP and KSB546YTU?

A: Both devices use TO-220-3 through-hole packages. The 2SB861-B-BP is supplied in bulk packaging, while the KSB546YTU is supplied in tube packaging. This difference affects handling and storage but does not impact electrical or mechanical compatibility.

Q: What is the significance of the product status difference?

A: The 2SB861-B-BP is classified as obsolete, indicating discontinued production and limited availability. The KSB546YTU is classified as Last Time Buy, indicating a final production run with defined end-of-life date. Designers should establish procurement timelines accordingly.

Q: Do both devices meet the same compliance standards?

A: Yes. Both the 2SB861-B-BP and KSB546YTU are ROHS3 compliant. Both carry EAR99 ECCN classification and identical HTSUS codes (8541.29.0095).

Q: Is the lower operating temperature limit of the KSB546YTU a concern?

A: The KSB546YTU datasheet specifies 150°C maximum junction temperature but does not explicitly state a minimum operating temperature. The 2SB861-B-BP supports −55°C to 150°C operation. Applications requiring sub-zero operation require confirmation of the KSB546YTU's lower temperature capability through the manufacturer's detailed specifications.

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