BC858B Equivalent & Substitute Parts

Part Overview

The BC858B is a PNP bipolar junction transistor manufactured by Taiwan Semiconductor Corporation, designed for surface mount applications in the SOT-23 package. This device operates at a maximum collector current of 100 mA, collector-emitter breakdown voltage of 30 V, and maximum power dissipation of 200 mW. The BC858B is classified as an active product with full RoHS3 compliance and REACH unaffected status. Equivalent and substitute parts are identified to address inventory availability, manufacturing discontinuation, or specific application requirements while maintaining electrical and mechanical compatibility within defined parameter tolerances.

Key Parameters

Parameter	Value	Unit
Transistor Type	PNP	—
Current - Collector (Ic) Max	100	mA
Voltage - Collector Emitter Breakdown (Max)	30	V
Vce Saturation (Max) @ Ib, Ic	650 mV @ 5 mA, 100 mA	—
Current - Collector Cutoff (Max)	100	nA
DC Current Gain (hFE) Min @ Ic, Vce	220 @ 2 mA, 5 V	—
Power - Max	200	mW
Frequency - Transition	100	MHz
Operating Temperature Range	-55 to 150	°C
Mounting Type	Surface Mount	—
Package / Case	TO-236-3, SC-59, SOT-23-3	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitute parts for the BC858B are classified into two categories based on electrical parameter alignment and product status:

Parametric Equivalent: Parts that maintain identical electrical specifications across all critical parameters including collector current, breakdown voltage, saturation voltage, current gain, power dissipation, and transition frequency. These parts differ only in packaging format (Tape & Reel versus bulk) or manufacturer source.

Similar Manufacturer Parts: Parts that share the same base product number (BC858) and maintain compatibility in collector current, breakdown voltage, and saturation voltage characteristics. These parts may exhibit variations in transition frequency, power dissipation, current gain, or collector cutoff current. Substitution is permissible when application requirements accommodate these parameter differences.

Critical Substitution Parameters:

Transistor Type: PNP (mandatory match)
Current - Collector (Ic) Max: 100 mA (mandatory match)
Voltage - Collector Emitter Breakdown: 30 V minimum (mandatory match)
Vce Saturation: 650 mV @ 5 mA, 100 mA (mandatory match)
Package / Case: TO-236-3, SC-59, SOT-23-3 (mandatory match)
Mounting Type: Surface Mount (mandatory match)

Parameter Comparison

Part Number	Manufacturer	Ic Max (mA)	Vce Breakdown (V)	Vce Sat (mV)	hFE Min @ 2mA, 5V	Power Max (mW)	Frequency (MHz)	Icbo Max (nA)	Product Status	Package
BC858B	Taiwan Semiconductor	100	30	650	220	200	100	100	Active	SOT-23
BC858B RFG	Taiwan Semiconductor	100	30	650	220	200	100	100	Active	SOT-23
BC858CLT3G	onsemi	100	30	650	420	300	100	15	Active	SOT-23-3
BC858BE6327HTSA1	Infineon Technologies	100	30	650	220	330	250	15	Last Time Buy	PG-SOT23
BC858CE6327HTSA1	Infineon Technologies	100	30	650	420	330	250	15	Last Time Buy	PG-SOT23
BCW61DE6327HTSA1	Infineon Technologies	100	32	550	380	330	250	20	Obsolete	PG-SOT23

Engineering Selection Recommendations

Primary Equivalent Selection: BC858B RFG is the direct parametric equivalent to BC858B. Both parts are manufactured by Taiwan Semiconductor Corporation and maintain identical electrical specifications. The only distinction is packaging format: BC858B RFG is supplied in Tape & Reel format while BC858B is supplied in standard packaging. Both parts carry Active product status and full RoHS3 compliance. Selection between these two parts depends solely on procurement and assembly requirements.

Active Product Alternatives: BC858CLT3G, manufactured by onsemi, is an active product offering enhanced electrical performance. This part maintains the mandatory electrical parameters (100 mA collector current, 30 V breakdown voltage, 650 mV saturation voltage) while providing higher DC current gain (420 versus 220), increased power dissipation capability (300 mW versus 200 mW), and improved collector cutoff current specification (15 nA versus 100 nA). The BC858CLT3G is suitable for applications where enhanced performance margins are beneficial.

Discontinued Product Alternatives: BC858BE6327HTSA1 and BC858CE6327HTSA1, both manufactured by Infineon Technologies, carry Last Time Buy status. These parts maintain the mandatory electrical parameters but offer enhanced transition frequency (250 MHz versus 100 MHz) and increased power dissipation (330 mW versus 200 mW). The BC858CE6327HTSA1 additionally provides higher DC current gain (420 versus 220). These parts are suitable for applications requiring higher frequency performance but should not be selected for new designs due to discontinued status.

Obsolete Parts: BCW61DE6327HTSA1 is classified as obsolete and should not be selected for any application. This part exhibits parameter deviations including higher breakdown voltage (32 V versus 30 V) and different saturation voltage characteristics (550 mV @ 1.25 mA, 50 mA versus 650 mV @ 5 mA, 100 mA), which violate mandatory substitution criteria.

Frequently Asked Questions (FAQ)

Q: Can BC858B RFG be used as a direct replacement for BC858B?

A: Yes. BC858B RFG is a parametric equivalent manufactured by Taiwan Semiconductor Corporation with identical electrical specifications. The difference is packaging format: BC858B RFG is supplied in Tape & Reel format for automated assembly, while BC858B is supplied in standard packaging. Both parts are Active products with full RoHS3 compliance.

Q: What are the key differences between BC858B and BC858CLT3G?

A: Both parts maintain the mandatory electrical parameters for substitution: 100 mA collector current, 30 V breakdown voltage, and 650 mV saturation voltage. BC858CLT3G, manufactured by onsemi, provides enhanced performance with higher DC current gain (420 versus 220), increased power dissipation capability (300 mW versus 200 mW), and improved collector cutoff current (15 nA versus 100 nA). BC858CLT3G is an active product suitable for new designs.

Q: Why are BC858BE6327HTSA1 and BC858CE6327HTSA1 marked as Last Time Buy?

A: These Infineon Technologies parts are in Last Time Buy status, indicating the manufacturer has discontinued production. While these parts maintain the mandatory electrical parameters for substitution, they should not be selected for new product designs. Existing inventory may be available for legacy system support only.

Q: Can BCW61DE6327HTSA1 be used as a substitute for BC858B?

A: No. BCW61DE6327HTSA1 is classified as obsolete and exhibits parameter deviations that violate substitution criteria. The breakdown voltage is 32 V (versus 30 V) and saturation voltage characteristics differ (550 mV @ 1.25 mA, 50 mA versus 650 mV @ 5 mA, 100 mA). This part is not suitable for any application requiring BC858B compatibility.

Q: What packaging formats are available for BC858B equivalents?

A: BC858B is available in standard SOT-23 packaging. BC858B RFG is supplied in Tape & Reel format for automated assembly. BC858CLT3G is supplied in SOT-23-3 (TO-236) format. Infineon parts (BC858BE6327HTSA1, BC858CE6327HTSA1, BCW61DE6327HTSA1) are supplied in PG-SOT23 format. All packages are mechanically compatible with TO-236-3, SC-59, SOT-23-3 specifications.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All substitute parts listed in this reference maintain RoHS3 compliance and REACH unaffected status, matching the compliance profile of the BC858B.

Q: What is the operating temperature range for BC858B substitutes?

A: BC858B and BC858CLT3G both specify operating temperature range of -55°C to 150°C. Infineon parts (BC858BE6327HTSA1, BC858CE6327HTSA1, BCW61DE6327HTSA1) specify maximum operating temperature of 150°C without lower temperature specification in the provided data. Applications requiring full -55°C to 150°C range should prioritize Taiwan Semiconductor or onsemi sources.

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