BC858A-TP Equivalent & Substitute Parts

Part Overview

The BC858A-TP is an active PNP bipolar junction transistor manufactured by Micro Commercial Co, designed for general-purpose switching and amplification applications. This surface mount device operates at 30 V maximum collector-emitter breakdown voltage with a maximum collector current of 100 mA and 200 mW power dissipation. The BC858A-TP is packaged in SOT-23 (TO-236-3) configuration for compact circuit integration.

Substitute parts are necessary when the original BC858A-TP is unavailable, when alternative packaging formats are required for manufacturing processes, or when enhanced performance specifications are beneficial for specific circuit requirements while maintaining functional compatibility.

Key Parameters

Parameter	BC858A-TP	Unit
Transistor Type	PNP	—
Current - Collector (Ic) Max	100	mA
Voltage - Collector Emitter Breakdown (Max)	30	V
Vce Saturation (Max) @ Ib, Ic	650mV @ 5mA, 100mA	—
Current - Collector Cutoff (Max)	15	nA
DC Current Gain (hFE) Min @ Ic, Vce	125 @ 2mA, 5V	—
Power - Max	200	mW
Frequency - Transition	100	MHz
Operating Temperature Range	-55 to 150	°C
Mounting Type	Surface Mount	—
Package / Case	SOT-23-3 (TO-236-3)	—

Substitute Part Grouping Explanation

Substitution compatibility for the BC858A-TP is determined by the following critical parameters:

Mandatory Matching Parameters:

Transistor Type: PNP
Current - Collector (Ic) Max: 100 mA (minimum requirement)
Voltage - Collector Emitter Breakdown: 30 V or greater
Vce Saturation: 650 mV @ 5mA, 100mA (maximum)
Operating Temperature Range: Must encompass -55°C to 150°C
Package / Case: SOT-23-3 (TO-236-3) or equivalent mechanical footprint

Allowable Variation Parameters:

DC Current Gain (hFE): May exceed 125 @ 2mA, 5V minimum
Power - Max: May exceed 200 mW
Frequency - Transition: May equal or exceed 100 MHz
Current - Collector Cutoff (Max): May be lower than 15 nA
Packaging Format: Bulk, Tape & Reel, or Cut Tape acceptable

Substitute parts are grouped into three categories based on electrical performance alignment and packaging availability.

Parameter Comparison

Part Number	Manufacturer	Ic (Max) mA	Vce(br) V	hFE Min @ 2mA, 5V	Power Max mW	Freq MHz	Package	Packaging Format
BC858A-TP	Micro Commercial Co	100	30	125	200	100	SOT-23-3	Bulk
BC858A RFG	Taiwan Semiconductor Corporation	100	30	125	200	100	SOT-23-3	Tape & Reel
BC858B RFG	Taiwan Semiconductor Corporation	100	30	220	200	100	SOT-23-3	Tape & Reel
BC858BLT1G	onsemi	100	30	220	300	100	SOT-23-3	Cut Tape & Digi-Reel
BC858BLT3G	onsemi	100	30	220	300	100	SOT-23-3	Tape & Reel
BC858C RFG	Taiwan Semiconductor Corporation	100	30	420	200	100	SOT-23-3	Tape & Reel
BC859C,235	Nexperia USA Inc.	100	30	420	250	100	SOT-23-3	Tape & Reel
BCW30LT1G	onsemi	100	32	215	300	—	SOT-23-3	Tape & Reel
BCW61B,215	Nexperia USA Inc.	100	32	180	250	100	SOT-23-3	Tape & Reel

Engineering Selection Recommendations

Category 1: Direct Electrical Equivalents (30 V Breakdown)

BC858A RFG, BC858B RFG, BC858BLT1G, BC858BLT3G, BC858C RFG, and BC859C,235 maintain the 30 V collector-emitter breakdown voltage specification identical to the BC858A-TP. These parts are electrically interchangeable within circuits designed for 30 V maximum operating conditions.

BC858A RFG provides identical electrical specifications with Tape & Reel packaging. BC858B RFG and BC858BLT variants offer increased DC current gain (220 minimum) with enhanced power dissipation (300 mW for onsemi variants), providing improved performance margin in switching applications. BC858C RFG and BC859C,235 provide the highest DC current gain (420 minimum), suitable for low-base-current driver applications.

BC859C,235 carries AEC-Q101 automotive qualification and is suitable for automotive-grade applications requiring enhanced reliability documentation.

Category 2: Enhanced Voltage Rating Substitutes (32 V Breakdown)

BCW30LT1G and BCW61B,215 provide 32 V collector-emitter breakdown voltage, exceeding the 30 V specification of the BC858A-TP. These parts are suitable for circuits where additional voltage margin is beneficial. BCW30LT1G offers 300 mW power dissipation and 215 minimum DC current gain. BCW61B,215 carries AEC-Q101 automotive qualification with 250 mW power dissipation and 180 minimum DC current gain.

Compliance and Certification:

All substitute parts maintain RoHS3 compliance, REACH unaffected status, and Moisture Sensitivity Level 1 (unlimited). BC859C,235 and BCW61B,215 carry AEC-Q101 automotive qualification for applications requiring automotive-grade component certification.

Frequently Asked Questions (FAQ)

Q: Can BC858B RFG replace BC858A-TP in all applications?

A: BC858B RFG is electrically compatible with BC858A-TP. Both maintain 30 V breakdown voltage, 100 mA maximum collector current, and 100 MHz transition frequency. BC858B RFG provides higher DC current gain (220 minimum versus 125 minimum), which may reduce base drive requirements in switching circuits. The primary difference is packaging format: BC858B RFG is supplied in Tape & Reel format while BC858A-TP is supplied in Bulk.

Q: What is the difference between BC858BLT1G and BC858BLT3G?

A: BC858BLT1G and BC858BLT3G are electrically identical. Both are manufactured by onsemi with 30 V breakdown voltage, 100 mA collector current, 220 minimum DC current gain, and 300 mW power dissipation. The difference is packaging format: BC858BLT1G is supplied in Cut Tape & Digi-Reel format, while BC858BLT3G is supplied in standard Tape & Reel format.

Q: When should BCW30LT1G or BCW61B,215 be selected instead of BC858 variants?

A: BCW30LT1G and BCW61B,215 provide 32 V collector-emitter breakdown voltage compared to 30 V for BC858 variants. Select these parts when circuit design requires additional voltage margin above 30 V, or when enhanced power dissipation capability (300 mW for BCW30LT1G, 250 mW for BCW61B,215) is necessary. BCW61B,215 is preferred for automotive applications due to AEC-Q101 qualification.

Q: Are all substitute parts compatible with the SOT-23 footprint?

A: All substitute parts listed are packaged in SOT-23-3 (TO-236-3) or TO-236AB configuration, which share identical mechanical footprints and pin assignments. Direct PCB footprint compatibility is maintained across all substitutes.

Q: What is the significance of DC current gain (hFE) variation among substitutes?

A: DC current gain variation affects base drive requirements in switching circuits. BC858A-TP specifies 125 minimum hFE, while BC858C RFG and BC859C,235 specify 420 minimum hFE. Higher hFE reduces required base current for saturation, potentially improving switching speed and reducing power dissipation in base drive circuits. Lower hFE (BCW61B,215 at 180 minimum) requires higher base drive but may provide more predictable gain characteristics in certain applications.

Q: Can BC859C,235 be used in non-automotive applications?

A: Yes. BC859C,235 is qualified for automotive applications (AEC-Q101) but is fully functional in general-purpose applications. The automotive qualification indicates enhanced reliability testing and documentation, making it suitable for any application requiring high reliability. Electrical specifications are identical to other 30 V BC858 variants with 420 minimum DC current gain.

Q: What packaging format should be selected for high-volume manufacturing?

A: Tape & Reel format (BC858A RFG, BC858B RFG, BC858BLT3G, BC858C RFG, BC859C,235, BCW30LT1G, BCW61B,215) is standard for automated pick-and-place assembly. Cut Tape & Digi-Reel format (BC858BLT1G) is suitable for lower-volume or mixed-component assembly. Bulk format (BC858A-TP) is used for manual assembly or component stocking.

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