BC858AMTF Equivalent & Substitute Parts

Part Overview

The BC858AMTF is a PNP bipolar junction transistor manufactured by onsemi, designed for general-purpose switching and amplification applications in surface mount configurations. This device operates at a maximum collector current of 100 mA with a collector-emitter breakdown voltage of 30 V and a maximum power dissipation of 310 mW. The BC858AMTF is classified as obsolete, which necessitates identification of active equivalent and substitute parts for new designs and ongoing production requirements. Substitute parts must maintain electrical compatibility within the specified parameter ranges while offering active product status and current manufacturing availability.

Key Parameters

Parameter	BC858AMTF 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)	15	nA
DC Current Gain (hFE) (Min) @ Ic, Vce	110 @ 2 mA, 5 V	—
Power - Max	310	mW
Frequency - Transition	150	MHz
Package / Case	SOT-23-3 (TO-236-3, SC-59)	—
Mounting Type	Surface Mount	—
Operating Temperature (Max)	150	°C
Product Status	Obsolete	—

Substitute Part Grouping Explanation

Substitute parts for the BC858AMTF are selected based on strict electrical and mechanical compatibility criteria. The primary substitution parameters are:

Transistor Type: Must be PNP
Package / Case: Must be SOT-23-3 (TO-236-3, SC-59) for mechanical and thermal compatibility
Current - Collector (Ic) (Max): Must be ≥ 100 mA
Voltage - Collector Emitter Breakdown (Max): Must be ≥ 30 V
Power - Max: Must be ≥ 310 mW (or ≥ 300 mW for active variants with equivalent thermal performance)
Vce Saturation: Must not exceed 650 mV @ 5 mA, 100 mA
Current - Collector Cutoff (Max): Must not exceed 15 nA (ICBO)

Substitute parts are grouped into two categories:

Category A: Direct BC858 Variants (Active Status) These parts share the BC858 base product number and maintain identical electrical specifications with active product status and RoHS3 compliance. These include BC858ALT1G, BC858BLT1G, BC858BLT3G, BC858CLT1G, and BC858CLT3G. Differences exist in DC current gain (hFE) ranges and packaging formats (Cut Tape or Tape & Reel), but all meet or exceed the BC858AMTF electrical requirements.

Category B: Alternative PNP Transistors (Active Status) These parts include BCW30LT1G, SBCW30LT1G, NSVBC858BLT1G, NSVBC858CLT1G, and 2SB1695KT146. These devices maintain PNP type and SOT-23-3 packaging with active product status. BCW30LT1G and SBCW30LT1G offer slightly higher breakdown voltage (32 V) and different saturation characteristics. NSVBC858 variants are automotive-qualified alternatives. The 2SB1695KT146 exceeds current rating (1.5 A) and offers higher transition frequency (280 MHz) but maintains 30 V breakdown voltage and SOT-23-3 packaging.

Parameter Comparison

Part Number	Manufacturer	Ic (Max) mA	Vce Breakdown (Max) V	Vce Sat (Max) mV	hFE (Min) @ 2mA, 5V	Power (Max) mW	Freq - Transition MHz	Temp Range °C	Product Status	RoHS3
BC858AMTF	onsemi	100	30	650	110	310	150	0 to 150	Obsolete	—
BC858ALT1G	onsemi	100	30	650	125	300	100	-55 to 150	Active	Yes
BC858BLT1G	onsemi	100	30	650	220	300	100	-55 to 150	Active	Yes
BC858BLT3G	onsemi	100	30	650	220	300	100	-55 to 150	Active	Yes
BC858CLT1G	onsemi	100	30	650	420	300	100	-55 to 150	Active	Yes
BC858CLT3G	onsemi	100	30	650	420	300	100	-55 to 150	Active	Yes
BCW30LT1G	onsemi	100	32	300	215	300	—	-65 to 150	Active	Yes
NSVBC858BLT1G	onsemi	100	30	650	220	300	100	-55 to 150	Active	Yes
NSVBC858CLT1G	onsemi	100	30	650	420	300	100	-55 to 150	Active	Yes
SBCW30LT1G	onsemi	100	32	300	215	300	—	-55 to 150	Active	Yes
2SB1695KT146	Rohm Semiconductor	1500	30	370	270	200	280	0 to 150	Active	Yes

Engineering Selection Recommendations

Primary Substitutes (Recommended for Direct Replacement)

BC858BLT1G, BC858BLT3G, BC858CLT1G, and BC858CLT3G are the preferred substitutes for the BC858AMTF. These parts maintain identical electrical specifications (30 V breakdown, 100 mA collector current, 650 mV saturation voltage, SOT-23-3 packaging) while offering active product status and RoHS3 compliance. The primary difference is reduced maximum power dissipation (300 mW versus 310 mW), which is acceptable for most applications within the BC858 design envelope. These variants differ only in DC current gain (hFE) ranges: BC858BLT variants specify 220 minimum, while BC858CLT variants specify 420 minimum. Selection between these should be based on circuit gain requirements.

BC858ALT1G is also a direct substitute with identical electrical parameters and active status, though it specifies a lower hFE minimum (125) compared to the BC858AMTF (110), making it suitable for applications requiring lower current gain.

Alternative Substitutes (Extended Operating Range)

NSVBC858BLT1G and NSVBC858CLT1G are automotive-qualified variants (AEC-Q101) with identical electrical specifications to their standard BC858 counterparts. These are suitable for applications requiring automotive-grade reliability and traceability.

BCW30LT1G and SBCW30LT1G offer higher collector-emitter breakdown voltage (32 V versus 30 V) and lower saturation voltage (300 mV versus 650 mV), providing improved performance margins in switching applications. SBCW30LT1G includes automotive qualification (AEC-Q101). These parts are suitable when enhanced voltage headroom or reduced saturation losses are beneficial.

Higher Current Alternative

2SB1695KT146 from Rohm Semiconductor is suitable only for applications requiring collector currents exceeding 100 mA. This part specifies 1.5 A maximum collector current and 280 MHz transition frequency, exceeding BC858AMTF capabilities. Use this substitute only when higher current capacity is a design requirement, as it introduces unnecessary complexity for standard 100 mA applications.

All recommended substitutes maintain SOT-23-3 packaging compatibility, surface mount mounting type, and REACH compliance status with the BC858AMTF.

Frequently Asked Questions (FAQ)

Q: Can BC858BLT1G directly replace BC858AMTF in existing designs?

A: Yes. BC858BLT1G maintains identical electrical specifications for collector current (100 mA), breakdown voltage (30 V), saturation voltage (650 mV @ 5 mA, 100 mA), and package type (SOT-23-3). The maximum power dissipation is 300 mW versus 310 mW for the BC858AMTF, which is acceptable for applications designed within the BC858 envelope. Pin configuration and package dimensions are identical.

Q: What is the difference between BC858ALT1G, BC858BLT1G, and BC858CLT1G?

A: These three parts differ only in DC current gain (hFE) specification at 2 mA, 5 V: BC858ALT1G specifies 125 minimum, BC858BLT1G specifies 220 minimum, and BC858CLT1G specifies 420 minimum. All other electrical parameters are identical. Selection depends on circuit design requirements for current gain. Higher hFE variants (BC858CLT1G) require less base current for a given collector current.

Q: What is the difference between Cut Tape (CT) and Tape & Reel (TR) packaging?

A: Cut Tape and Tape & Reel refer to supply formats, not the component itself. Both formats contain identical BC858 transistors in SOT-23-3 packages. Cut Tape is suitable for small-quantity orders and manual assembly, while Tape & Reel is optimized for high-volume automated pick-and-place assembly. Electrical performance is identical between formats.

Q: Can BCW30LT1G replace BC858AMTF?

A: BCW30LT1G is electrically compatible with BC858AMTF for most applications. It maintains 100 mA collector current and SOT-23-3 packaging. However, BCW30LT1G specifies 32 V breakdown voltage (versus 30 V) and 300 mV saturation voltage (versus 650 mV). The lower saturation voltage reduces power dissipation in switching applications, which is beneficial. Use BCW30LT1G when improved switching performance or higher voltage margin is required.

Q: Is SBCW30LT1G suitable for automotive applications?

A: Yes. SBCW30LT1G is qualified to AEC-Q101 automotive standard and carries automotive-grade designation. It maintains identical electrical specifications to BCW30LT1G (32 V breakdown, 100 mA collector current, 300 mV saturation, SOT-23-3 package) with extended operating temperature range (-55°C to 150°C). Use SBCW30LT1G for automotive designs requiring automotive-qualified components.

Q: When should 2SB1695KT146 be used instead of BC858 variants?

A: 2SB1695KT146 should be used only when collector current requirements exceed 100 mA. This part specifies 1.5 A maximum collector current and 280 MHz transition frequency, significantly exceeding BC858 capabilities. For standard applications requiring 100 mA or less, BC858 variants are more appropriate and cost-effective.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All active substitute parts listed (BC858ALT1G, BC858BLT1G, BC858BLT3G, BC858CLT1G, BC858CLT3G, BCW30LT1G, NSVBC858BLT1G, NSVBC858CLT1G, SBCW30LT1G, and 2SB1695KT146) are RoHS3 compliant. The obsolete BC858AMTF does not specify RoHS status.

Q: What is the difference between standard BC858 and NSVBC858 variants?

A: NSVBC858 variants are automotive-qualified versions of BC858 transistors. NSVBC858BLT1G and NSVBC858CLT1G maintain identical electrical specifications to their BC858 counterparts (BC858BLT1G and BC858CLT1G respectively) but include AEC-Q101 automotive qualification. Use NSVBC858 variants for automotive applications requiring qualified component traceability.

Q: Can I use BC858CLT1G in place of BC858ALT1G?

A: Yes. BC858CLT1G is a direct substitute for BC858ALT1G. Both maintain identical electrical specifications (30 V breakdown, 100 mA collector current, 650 mV saturation, 100 MHz transition frequency, SOT-23-3 package). The only difference is DC current gain: BC858CLT1G specifies 420 minimum hFE versus 125 minimum for BC858ALT1G. BC858CLT1G is suitable for any application designed for BC858ALT1G.

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