BC858CMTF PNP Bipolar Transistor Equivalent & Substitute Parts

Part Overview

The BC858CMTF is a PNP bipolar junction transistor manufactured by onsemi, designed for general-purpose switching and amplification applications. This device operates at a maximum collector current of 100 mA with a collector-emitter breakdown voltage of 30 V and a transition frequency of 150 MHz. The BC858CMTF is packaged in the SOT-23-3 (TO-236-3) surface mount configuration with a maximum power dissipation of 310 mW.

The BC858CMTF is classified as an obsolete product. Equivalent and substitute parts are necessary to maintain design continuity, ensure supply chain availability, and support ongoing production requirements. Active alternatives with identical or superior electrical characteristics are available from the same manufacturer.

Key Parameters

Parameter	BC858CMTF 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	420 @ 2 mA, 5 V	—
Power - Max	310	mW
Frequency - Transition	150	MHz
Package / Case	SOT-23-3 (TO-236-3)	—
Mounting Type	Surface Mount	—
Operating Temperature (Max)	150	°C
RoHS Status	ROHS3 Compliant	—
Moisture Sensitivity Level (MSL)	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitute parts for the BC858CMTF are classified into two categories based on electrical parameter compatibility:

Direct Substitutes (Functionally Equivalent): Parts that maintain identical or superior performance within the critical operating parameters of the BC858CMTF. These substitutes share the same PNP transistor type, 30 V collector-emitter breakdown voltage, 100 mA maximum collector current, SOT-23-3 package configuration, and surface mount mounting type. Direct substitutes include NSVBC858CLT1G, BC858ALT1G, BC858BLT1G, BC858BLT3G, BC858CLT1G, and BC858CLT3G. These parts are all active products with ROHS3 compliance and MSL 1 rating.

Similar Substitutes (Parameter Variations): Parts that maintain the same package type and mounting configuration but feature variations in one or more electrical parameters. These include BCW30LT1G (32 V breakdown voltage), FMMT549 (1 A collector current), MMBT589LT1G (1 A collector current), and 30A02CH-TL-E (higher current and frequency ratings with different package variant). Similar substitutes are selected when design requirements permit parameter flexibility.

The substitution logic is based strictly on the following key parameters: transistor type (PNP), collector-emitter breakdown voltage (30 V or higher), maximum collector current (100 mA or higher), package type (SOT-23-3), mounting type (surface mount), and compliance certifications (ROHS3, MSL 1).

Parameter Comparison

Part Number	Manufacturer	Product Status	Ic (Max) mA	Vce Breakdown (Max) V	Vce Sat (Max) mV	hFE (Min)	Power (Max) mW	Frequency MHz	Package	Temp Range °C
BC858CMTF	onsemi	Obsolete	100	30	650	420	310	150	SOT-23-3	0 to 150
NSVBC858CLT1G	onsemi	Active	100	30	650	420	300	100	SOT-23-3	-55 to 150
BC858ALT1G	onsemi	Active	100	30	650	125	300	100	SOT-23-3	-55 to 150
BC858BLT1G	onsemi	Active	100	30	650	220	300	100	SOT-23-3	-55 to 150
BC858BLT3G	onsemi	Active	100	30	650	220	300	100	SOT-23-3	-55 to 150
BC858CLT1G	onsemi	Active	100	30	650	420	300	100	SOT-23-3	-55 to 150
BC858CLT3G	onsemi	Active	100	30	650	420	300	100	SOT-23-3	-55 to 150
BCW30LT1G	onsemi	Active	100	32	300	215	300	—	SOT-23-3	-65 to 150
FMMT549	onsemi	Active	1000	30	750	100	500	100	SOT-23-3	0 to 150
MMBT589LT1G	onsemi	Active	1000	30	650	100	310	100	SOT-23-3	-55 to 150
30A02CH-TL-E	onsemi	Active	700	30	220	200	700	520	3-CPH	0 to 150

Engineering Selection Recommendations

For Direct Replacement (Identical Electrical Performance):

BC858CLT1G and BC858CLT3G are the primary recommended substitutes for the BC858CMTF. Both parts maintain the same DC current gain (hFE minimum of 420 @ 2 mA, 5 V), collector-emitter breakdown voltage (30 V), maximum collector current (100 mA), and saturation voltage (650 mV @ 5 mA, 100 mA). These parts are active products with ROHS3 compliance and MSL 1 rating. The difference between CLT1G and CLT3G is packaging format: CLT1G is supplied in cut tape configuration, while CLT3G is supplied in tape and reel format. Selection between these variants depends on procurement and assembly requirements.

NSVBC858CLT1G is an alternative direct substitute with identical electrical specifications to BC858CLT1G, also available in tape and reel packaging. This part is suitable for high-volume production environments.

For Applications Permitting Parameter Variation:

BC858ALT1G and BC858BLT1G offer active product status with extended operating temperature range (-55°C to 150°C) compared to the BC858CMTF. These parts maintain the 30 V breakdown voltage and 100 mA collector current but feature lower DC current gain values (125 and 220 respectively). Selection of these parts is appropriate when the application circuit can accommodate the reduced gain specification.

BCW30LT1G provides a 32 V collector-emitter breakdown voltage, offering enhanced voltage margin. This part is suitable for applications requiring higher voltage headroom while maintaining the 100 mA current rating and SOT-23-3 package.

For Higher Current Applications:

FMMT549 and MMBT589LT1G support 1 A maximum collector current while maintaining the 30 V breakdown voltage and SOT-23-3 package. These parts are suitable for applications requiring higher current capacity than the BC858CMTF specification. MMBT589LT1G provides extended temperature range (-55°C to 150°C) and is the preferred selection for temperature-critical designs.

For High-Frequency Applications:

30A02CH-TL-E features a 520 MHz transition frequency, significantly higher than the BC858CMTF specification. This part supports 700 mA collector current and is packaged in the 3-CPH variant. Selection of this part is appropriate only when the application requires enhanced frequency response and the different package configuration is acceptable.

All recommended substitutes maintain ROHS3 compliance and MSL 1 moisture sensitivity rating, ensuring compatibility with standard manufacturing and storage protocols.

Frequently Asked Questions (FAQ)

Q: Can BC858CLT1G be used as a direct replacement for BC858CMTF in all applications?

A: BC858CLT1G is electrically equivalent to BC858CMTF within the specified operating parameters. Both parts share identical maximum collector current (100 mA), collector-emitter breakdown voltage (30 V), DC current gain (420 @ 2 mA, 5 V), and saturation voltage (650 mV @ 5 mA, 100 mA). The primary difference is that BC858CLT1G is an active product with extended operating temperature range (-55°C to 150°C) compared to BC858CMTF (0°C to 150°C). BC858CLT1G is suitable for direct replacement in applications operating within the BC858CMTF temperature specification.

Q: What is the difference between BC858CLT1G and BC858CLT3G?

A: BC858CLT1G and BC858CLT3G are electrically identical parts with the same electrical specifications. The designation difference reflects packaging format: CLT1G is supplied in cut tape (CT) and Digi-Reel configuration, while CLT3G is supplied in tape and reel (TR) format. Selection between these variants depends on procurement method and assembly equipment compatibility. Both parts are suitable for direct replacement of BC858CMTF.

Q: Why does NSVBC858CLT1G have lower maximum power dissipation (300 mW) compared to BC858CMTF (310 mW)?

A: The 10 mW difference in maximum power dissipation does not affect functional equivalence for the BC858CMTF application. Both parts maintain identical electrical performance at the specified operating points. The power dissipation specification represents the absolute maximum rating under worst-case conditions. For typical circuit operation, this marginal difference is not significant. NSVBC858CLT1G is suitable for direct replacement.

Q: Can BC858ALT1G be used if the application requires the same DC current gain as BC858CMTF?

A: BC858ALT1G has a minimum DC current gain of 125 @ 2 mA, 5 V, compared to BC858CMTF specification of 420 @ 2 mA, 5 V. This represents a significant reduction in gain. BC858ALT1G is suitable only for applications where the circuit design can accommodate lower current gain. If the application requires the higher gain specification, BC858CLT1G or BC858CLT3G are the appropriate selections.

Q: Is BCW30LT1G compatible with BC858CMTF designs?

A: BCW30LT1G is compatible with BC858CMTF designs when the application permits a higher collector-emitter breakdown voltage (32 V versus 30 V). The 2 V increase in breakdown voltage provides additional voltage margin without affecting circuit operation at the BC858CMTF voltage specification. BCW30LT1G maintains the same maximum collector current (100 mA) and SOT-23-3 package. This part is suitable for applications requiring enhanced voltage headroom.

Q: When should FMMT549 or MMBT589LT1G be selected instead of BC858CLT1G?

A: FMMT549 and MMBT589LT1G support 1 A maximum collector current, compared to 100 mA for BC858CLT1G. These higher-current parts are selected when the application requires collector current exceeding 100 mA. Both parts maintain the 30 V collector-emitter breakdown voltage and SOT-23-3 package. MMBT589LT1G is preferred for temperature-critical applications due to its extended operating range (-55°C to 150°C).

Q: Is the 30A02CH-TL-E suitable as a substitute for BC858CMTF?

A: 30A02CH-TL-E is not a direct substitute for BC858CMTF. While both parts are PNP transistors with 30 V breakdown voltage, the 30A02CH-TL-E is packaged in the 3-CPH variant rather than SOT-23-3. Additionally, 30A02CH-TL-E supports 700 mA collector current and features a 520 MHz transition frequency, significantly different from BC858CMTF specifications. This part is suitable only for applications where the different package configuration is acceptable and higher current and frequency performance are required.

Q: Are all substitute parts ROHS3 compliant?

A: All substitute parts listed in this reference are ROHS3 compliant and carry MSL 1 (Unlimited) moisture sensitivity rating. This ensures compatibility with standard manufacturing processes and storage requirements equivalent to BC858CMTF.

Q: What is the impact of transition frequency differences between BC858CMTF (150 MHz) and substitute parts?

A: BC858CMTF specifies 150 MHz transition frequency. Most substitute parts (BC858ALT1G, BC858BLT1G, BC858CLT1G, BC858CLT3G, NSVBC858CLT1G, FMMT549, MMBT589LT1G) specify 100 MHz transition frequency. This 50 MHz reduction does not affect applications operating at frequencies significantly below 100 MHz. For applications requiring the full 150 MHz specification, BC858CMTF performance cannot be matched by available substitutes. BCW30LT1G does not specify transition frequency. 30A02CH-TL-E specifies 520 MHz, suitable for high-frequency applications.

Q: Can substitute parts be intermixed in production?

A: Substitute parts with identical electrical specifications (BC858CLT1G, BC858CLT3G, NSVBC858CLT1G) can be intermixed in production without circuit impact. Parts with parameter variations (BC858ALT1G, BC858BLT1G, BCW30LT1G) should be evaluated individually for circuit compatibility before intermixing. Higher-current parts (FMMT549, MMBT589LT1G) and the 30A02CH-TL-E should not be intermixed with BC858CMTF without circuit re-evaluation.

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