BC858A-HF Equivalent & Substitute Parts Reference

Part Overview

The BC858A-HF is a PNP bipolar junction transistor manufactured by Comchip Technology, 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 transition frequency of 100 MHz. The part is currently in active production status with 821 pieces available in inventory.

Substitute parts are identified when equivalent electrical performance and mechanical compatibility are maintained across the specified parameter ranges. The BC858A-HF serves as the reference baseline for identifying functionally compatible alternatives from multiple manufacturers.

Key Parameters

Parameter	Value	Unit
Transistor Type	PNP	—
Maximum Collector Current (Ic)	100	mA
Maximum Collector-Emitter Breakdown Voltage	30	V
Vce Saturation @ Ib, Ic	650 mV @ 5 mA, 100 mA	—
Maximum Collector Cutoff Current (ICBO)	15	nA
DC Current Gain (hFE) @ Ic, Vce	125 @ 2.2 mA, 5 V	—
Maximum Power Dissipation	250	mW
Transition Frequency (fT)	100	MHz
Operating Temperature Range	−65 to +150	°C
Package Type	SOT-23-3 (TO-236-3, SC-59)	—
Mounting Type	Surface Mount	—
RoHS Status	ROHS3 Compliant	—
Moisture Sensitivity Level	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitute parts are classified into three categories based on their relationship to the BC858A-HF reference part:

Upgrade Substitutes maintain all critical electrical parameters while offering enhanced specifications or higher availability. These parts are direct functional replacements with identical or superior performance characteristics.

Manufacturer Recommended Substitutes are designated by original equipment manufacturers as approved alternatives. These parts meet or exceed the baseline specifications and carry manufacturer qualification or automotive-grade certifications where applicable.

The substitution logic is based strictly on the following key parameters:

Transistor polarity (PNP)
Maximum collector current: 100 mA minimum
Maximum collector-emitter breakdown voltage: 30 V minimum
Vce saturation: 650 mV @ 5 mA, 100 mA
Maximum collector cutoff current: 15 nA or lower
DC current gain (hFE): minimum 125 @ specified conditions
Transition frequency: 100 MHz minimum
Package compatibility: SOT-23-3 / TO-236-3 / SC-59
Surface-mount configuration
RoHS3 compliance
MSL rating: 1 (Unlimited)

Parts that deviate from these parameters in ways that would affect circuit performance are excluded from the substitute list.

Parameter Comparison

Part Number	Manufacturer	Ic (Max) mA	Vce(br) V	hFE @ 2 mA, 5V	Power mW	fT MHz	Temp Range °C	Package	Status
BC858A-HF	Comchip Technology	100	30	125	250	100	−65 to +150	SOT-23-3	Active
BC858B,235	Nexperia USA Inc.	100	30	220	250	100	−55 to +150	TO-236AB	Active
BC859B,215	NXP Semiconductors	100	30	220	250	100	−55 to +150	TO-236AB	Active
BC859C,215	Nexperia USA Inc.	100	30	420	250	100	−55 to +150	TO-236AB	Active
BC858A RFG	Taiwan Semiconductor Corporation	100	30	125	200	100	−55 to +150	SOT-23	Active
BC858B RFG	Taiwan Semiconductor Corporation	100	30	220	200	100	−55 to +150	SOT-23	Active
BC858BE6327HTSA1	Infineon Technologies	100	30	220	330	250	−55 to +150	PG-SOT23	Last Time Buy
BC858BE6433HTMA1	Infineon Technologies	100	30	220	330	250	−55 to +150	PG-SOT23	Last Time Buy
BC858BLT3G	onsemi	100	30	220	300	100	−55 to +150	SOT-23-3	Active
BC858C RFG	Taiwan Semiconductor Corporation	100	30	420	200	100	−55 to +150	SOT-23	Active
BC859CE6327HTSA1	Infineon Technologies	100	30	420	330	250	−55 to +150	PG-SOT23	Last Time Buy

Engineering Selection Recommendations

For Active Production Applications:

BC858BLT3G (onsemi) is the primary recommended substitute. This part maintains 100 MHz transition frequency, 100 mA collector current, and 30 V breakdown voltage. The SOT-23-3 package provides direct mechanical compatibility with the BC858A-HF. Higher power dissipation rating (300 mW vs. 250 mW) offers additional thermal margin. Active product status ensures long-term availability and supply chain stability.

BC858B,235 (Nexperia USA Inc.) provides an alternative with automotive-grade qualification (AEC-Q101) and higher current gain (hFE = 220). TO-236AB package is mechanically compatible. Active status and high inventory (5756 pieces) support production requirements.

BC859B,215 (NXP Semiconductors) offers the highest inventory availability (9,498,645 pieces) with automotive qualification. Current gain of 220 and identical electrical specifications support direct substitution. Bulk packaging option provides cost efficiency for high-volume applications.

For Extended Temperature Range Requirements:

BC858A-HF specifies −65°C to +150°C operating range. All listed substitutes operate to −55°C minimum, which covers most industrial and commercial applications. Applications requiring −65°C operation should retain the BC858A-HF or verify circuit performance at the lower temperature limit with substitute parts.

For Power-Constrained Applications:

BC858A RFG and BC858C RFG (Taiwan Semiconductor Corporation) offer reduced power dissipation (200 mW) compared to the reference part (250 mW). These parts are suitable for applications where thermal management is critical. Active status and adequate inventory support production use.

For Enhanced Performance Applications:

BC858BE6327HTSA1 and BC858BE6433HTMA1 (Infineon Technologies) provide 250 MHz transition frequency and 330 mW power dissipation. These parts exceed baseline specifications but carry Last Time Buy status, indicating discontinued production. Use only when enhanced performance justifies supply chain risk.

BC859CE6327HTSA1 (Infineon Technologies) combines highest current gain (hFE = 420), enhanced transition frequency (250 MHz), and increased power rating (330 mW). Last Time Buy status requires inventory planning.

Compliance and Certification:

All listed parts maintain RoHS3 compliance and MSL rating of 1 (Unlimited). Nexperia and NXP parts carry AEC-Q101 automotive qualification, suitable for automotive and high-reliability applications. Taiwan Semiconductor Corporation parts are qualified for commercial and industrial use.

Frequently Asked Questions (FAQ)

Q: Can BC858B,235 directly replace BC858A-HF in existing designs?

A: Yes. Both parts maintain identical maximum ratings for collector current (100 mA), collector-emitter breakdown voltage (30 V), and saturation voltage (650 mV @ 5 mA, 100 mA). The higher current gain of BC858B,235 (hFE = 220 vs. 125) may require bias network adjustment in precision amplifier circuits, but switching applications tolerate this variation. Package compatibility (SOT-23-3 / TO-236AB) is confirmed.

Q: What is the difference between BC858 and BC859 series parts?

A: BC858 and BC859 are distinct part numbers within the same product family. Both are PNP transistors with identical maximum ratings (30 V, 100 mA, 100 MHz). The primary difference is DC current gain specification: BC858 series specifies hFE minimum of 125, while BC859 series specifies hFE minimum of 220. Selection depends on circuit bias requirements. Higher gain (BC859) reduces base current requirements; lower gain (BC858) provides more predictable saturation characteristics.

Q: Are Taiwan Semiconductor Corporation parts (RFG suffix) equivalent to Nexperia and NXP parts?

A: Yes, within specified electrical parameters. BC858A RFG, BC858B RFG, and BC858C RFG maintain identical maximum ratings and package compatibility. Power dissipation is reduced to 200 mW compared to 250 mW in Comchip and Nexperia versions. Operating temperature range is −55°C to +150°C (vs. −65°C to +150°C for BC858A-HF). These parts are suitable for applications not requiring −65°C operation.

Q: What does "Last Time Buy" status mean for Infineon parts?

A: Last Time Buy indicates the manufacturer has discontinued production and will accept orders only until a specified cutoff date. Existing inventory may be available, but long-term supply is not guaranteed. BC858BE6327HTSA1, BC858BE6433HTMA1, and BC859CE6327HTSA1 carry this status. Use these parts only when enhanced specifications (250 MHz, 330 mW) justify inventory risk, or transition to active-status alternatives.

Q: Can I use BC859C,215 instead of BC858A-HF for higher current gain?

A: Yes. BC859C,215 provides hFE minimum of 420 at identical test conditions (2 mA, 5 V). This higher gain reduces base current requirements and may improve circuit efficiency. All other electrical parameters (30 V, 100 mA, 100 MHz, 650 mV saturation) are identical. Package compatibility is confirmed. Verify bias network calculations for precision applications.

Q: Is the SOT-23-3 package identical to TO-236AB?

A: SOT-23-3, TO-236-3, SC-59, and TO-236AB are equivalent package designations for the same three-lead surface-mount component. Pin assignments and PCB footprints are identical. All listed substitute parts use compatible packages. Verify footprint dimensions with component datasheets before PCB layout.

Q: Which substitute part offers the best thermal performance?

A: BC858BE6327HTSA1 and BC858BE6433HTMA1 (Infineon) offer maximum power dissipation of 330 mW, compared to 250 mW for BC858A-HF. BC858BLT3G (onsemi) provides 300 mW. These parts dissipate more heat at equivalent current levels, reducing junction temperature rise. However, Last Time Buy status limits long-term availability for Infineon parts. BC858BLT3G is recommended for thermal-constrained applications with active production requirements.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All listed substitute parts carry RoHS3 compliance certification. Moisture sensitivity level is MSL 1 (Unlimited) for all parts, indicating no moisture-related handling restrictions during storage or assembly.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message