BC858B-QR Equivalent & Substitute Parts

Part Overview

The BC858B-QR is an active PNP bipolar junction transistor manufactured by Nexperia USA Inc., designed for small-signal switching and amplification applications. This surface-mount device operates at 30 V maximum collector-emitter voltage with a maximum collector current of 100 mA and delivers 250 mW power dissipation. The part is packaged in TO-236AB (SOT-23-3) configuration and carries AEC-Q101 automotive qualification with ROHS3 compliance. Equivalent and substitute parts are identified based on matching electrical specifications, package compatibility, and operational parameters that define functional interchangeability within circuit designs.

Key Parameters

Parameter	Value	Unit
Transistor Type	PNP	—
Collector-Emitter Breakdown Voltage (Max)	30	V
Collector Current (Max)	100	mA
Power Dissipation (Max)	250	mW
Transition Frequency	100	MHz
DC Current Gain (hFE) @ Ic=2mA, Vce=5V	220 (Min)	—
Vce Saturation @ Ib=5mA, Ic=100mA	650	mV
Collector Cutoff Current (ICBO)	15	nA
Operating Temperature (Max)	150	°C
Package / Case	TO-236-3, SC-59, SOT-23-3	—
Mounting Type	Surface Mount	—
Grade	Automotive	—
Qualification	AEC-Q101	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitute parts for the BC858B-QR are classified into two categories based on electrical and mechanical parameter alignment:

Parametric Equivalents share identical or functionally equivalent electrical specifications across all critical parameters: 30 V collector-emitter breakdown voltage, 100 mA maximum collector current, 100 MHz transition frequency, 220 minimum DC current gain at specified conditions, 650 mV Vce saturation, and surface-mount SOT-23-3 packaging. These parts are direct functional replacements within the same circuit topology.

Similar Parts maintain core electrical specifications (30 V, 100 mA, 100 MHz, SOT-23-3 package) but exhibit variations in secondary parameters such as power dissipation (200 mW versus 250 mW), collector cutoff current (100 nA versus 15 nA), or DC current gain ranges (125 or 420 versus 220). These parts function in equivalent applications but require verification of circuit margin requirements for the specific parameter variance.

Substitution eligibility is determined by:

Matching transistor type (PNP)
Matching or exceeding voltage rating (30 V minimum)
Matching or exceeding current rating (100 mA minimum)
Matching or exceeding power dissipation (250 mW for parametric equivalents; 200 mW acceptable for similar parts with circuit analysis)
Matching package footprint (TO-236-3, SC-59, SOT-23-3)
Matching or exceeding transition frequency (100 MHz)
Matching saturation voltage characteristics (650 mV @ 5mA, 100mA)

Parameter Comparison

Part Number	Manufacturer	Ic (Max) mA	Vce(br) V	Power mW	hFE @ 2mA, 5V	Vce Sat mV	ICBO nA	Freq MHz	Package	Grade	AEC-Q101
BC858B-QR	Nexperia USA Inc.	100	30	250	220	650	15	100	TO-236AB	Automotive	Yes
BC858B,215	Nexperia USA Inc.	100	30	250	220	650	15	100	TO-236AB	Automotive	Yes
BC858B,235	Nexperia USA Inc.	100	30	250	220	650	15	100	TO-236AB	Automotive	Yes
BC859B,215	NXP Semiconductors	100	30	250	220	650	15	100	TO-236AB	Automotive	Yes
BC858A RFG	Taiwan Semiconductor Corporation	100	30	200	125	650	100	100	SOT-23	—	—
BC858B RFG	Taiwan Semiconductor Corporation	100	30	200	220	650	100	100	SOT-23	—	—
BC858C RFG	Taiwan Semiconductor Corporation	100	30	200	420	650	100	100	SOT-23	—	—
BC858B	Taiwan Semiconductor Corporation	100	30	200	220	650	100	100	SOT-23	—	—
BC859B	Diotec Semiconductor	100	30	250	220	650	15	100	SOT-23-3	—	—

Engineering Selection Recommendations

Parametric Equivalent Selection (Direct Replacement)

BC858B,215, BC858B,235, BC859B,215, and BC859B from Diotec Semiconductor are parametric equivalents to the BC858B-QR. These parts maintain identical electrical specifications across all critical parameters and are suitable for direct substitution in automotive-grade applications. BC858B,215 and BC858B,235 from Nexperia USA Inc. carry AEC-Q101 qualification and automotive grade designation, matching the original part's compliance profile. BC859B,215 from NXP Semiconductors and BC859B from Diotec Semiconductor provide equivalent performance with matching 250 mW power dissipation and 15 nA collector cutoff current specifications.

Similar Part Selection (Application-Dependent)

BC858A RFG, BC858B RFG, BC858C RFG, and BC858B from Taiwan Semiconductor Corporation are similar parts with reduced power dissipation (200 mW versus 250 mW) and elevated collector cutoff current (100 nA versus 15 nA). These parts are suitable for applications where thermal margin is not critical and leakage current specifications are less stringent. The BC858C RFG variant exhibits elevated DC current gain (420 minimum) compared to the standard 220 specification, which may affect circuit biasing in gain-sensitive applications.

Compliance Considerations

For automotive applications requiring AEC-Q101 qualification, BC858B,215, BC858B,235, and BC859B,215 maintain the original part's certification status. Taiwan Semiconductor Corporation variants do not carry automotive grade or AEC-Q101 qualification and are restricted to non-automotive applications unless additional qualification documentation is obtained.

Package Compatibility

All listed parts employ SOT-23-3 or TO-236AB packaging with identical footprints (TO-236-3, SC-59, SOT-23-3 designations refer to the same physical package). Surface-mount assembly compatibility is maintained across all substitutes.

Frequently Asked Questions (FAQ)

Q: Can BC858B,215 replace BC858B-QR in automotive applications?

A: Yes. BC858B,215 is a parametric equivalent manufactured by Nexperia USA Inc. with identical electrical specifications, AEC-Q101 qualification, and automotive grade designation. Direct substitution is supported without circuit modification.

Q: What is the difference between BC858B-QR and BC859B?

A: BC858B-QR and BC859B are parametric equivalents sharing identical electrical specifications (30 V, 100 mA, 100 MHz, 250 mW, 220 hFE). The primary difference is manufacturer designation and packaging variant. Both are functionally interchangeable in circuit applications.

Q: Are Taiwan Semiconductor Corporation variants suitable for automotive use?

A: Taiwan Semiconductor Corporation BC858 variants (BC858A RFG, BC858B RFG, BC858C RFG, BC858B) do not carry automotive grade or AEC-Q101 qualification. These parts are restricted to non-automotive applications unless additional qualification documentation is provided by the supplier.

Q: Why do some substitutes show 200 mW power dissipation instead of 250 mW?

A: Taiwan Semiconductor Corporation and some other manufacturers specify 200 mW maximum power dissipation for the BC858 series, compared to 250 mW for Nexperia and Diotec variants. This represents a secondary parameter variance. Substitution is valid when circuit thermal analysis confirms that 200 mW dissipation capacity is sufficient for the application's power budget.

Q: What is the significance of collector cutoff current (ICBO) differences?

A: Nexperia and Diotec variants specify 15 nA maximum ICBO, while Taiwan Semiconductor Corporation parts specify 100 nA. Lower ICBO values indicate reduced leakage current and improved performance in high-impedance or precision analog circuits. For standard switching applications, both specifications are functionally equivalent.

Q: Can BC858C RFG be used where BC858B-QR is specified?

A: BC858C RFG exhibits elevated DC current gain (420 minimum versus 220 minimum). While electrically compatible, the higher gain may alter circuit biasing characteristics in gain-sensitive applications. Circuit analysis is required to confirm that the elevated gain does not compromise design margins or introduce instability.

Q: Are all substitutes available in the same package footprint?

A: Yes. All listed substitutes employ SOT-23-3 or TO-236AB packaging with identical physical footprints. Surface-mount assembly compatibility is maintained across all parts without PCB redesign.

Q: What packaging designation should I use when ordering substitutes?

A: Use the supplier device package designation provided by the manufacturer. Nexperia parts specify TO-236AB; Taiwan Semiconductor Corporation and Diotec parts specify SOT-23 or SOT-23-3. These designations refer to the same physical package and are interchangeable for PCB assembly purposes.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message