BC857CT,115 Equivalent & Substitute Parts Reference

Part Overview

The BC857CT,115 is a PNP bipolar junction transistor manufactured by NXP USA Inc., designed for general-purpose switching and amplification applications. This device features a 45 V collector-emitter breakdown voltage, 100 mA maximum collector current, and 150 mW power dissipation in an SC-75 surface mount package. The part is classified as obsolete, which necessitates identification of active equivalent and substitute components that maintain functional compatibility within the specified electrical and mechanical parameters.

Key Parameters

Parameter	Value	Unit
Transistor Type	PNP	—
Collector-Emitter Breakdown Voltage (Max)	45	V
Collector Current (Max)	100	mA
Power Dissipation (Max)	150	mW
Transition Frequency	100	MHz
DC Current Gain (hFE) @ Ic, Vce	420 @ 2mA, 5V	—
Vce Saturation (Max) @ Ib, Ic	400mV @ 5mA, 100mA	—
Collector Cutoff Current (Max)	15	nA
Operating Temperature (Max)	150	°C
Package Type	SC-75, SOT-416	—
Mounting Type	Surface Mount	—
Grade	Automotive	—
Qualification	AEC-Q101	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution of the BC857CT,115 is determined by strict adherence to the following electrical and mechanical parameters:

Primary Substitution Criteria:

Transistor type must be PNP
Collector-emitter breakdown voltage must be ≥45 V
Maximum collector current must be ≥100 mA
Maximum power dissipation must be ≥150 mW
Transition frequency must be ≥100 MHz
DC current gain (hFE) must support the application requirements
Collector cutoff current must be ≤15 nA or compatible with circuit design
Operating temperature range must include 150°C maximum junction temperature
Surface mount mounting type required
RoHS3 compliance required

Package Compatibility Considerations: Substitutes are grouped into three package categories: SC-75/SOT-416 (direct footprint match), SOT-23/TO-236-3 (alternative compact package), and SOT-323/SC-70 (ultra-compact package). Each category maintains electrical equivalence while offering different board layout options.

Parameter Comparison

Part Number	Manufacturer	Vce(BR) Max (V)	Ic Max (mA)	Power Max (mW)	fT (MHz)	hFE @ 2mA, 5V	Package	Status
BC857CT,115	NXP USA Inc.	45	100	150	100	420	SC-75	Obsolete
2SA1774T1G	onsemi	50	100	150	140	120	SC-75	Active
BC857A-TP	Micro Commercial Co	45	100	310	200	125	SOT-23	Active
BC857B-TP	Micro Commercial Co	45	100	310	200	220	SOT-23	Active
BC857BTT1G	onsemi	45	100	200	100	220	SC-75	Active
BC857BWT1G	onsemi	45	100	150	100	220	SC-70	Active
BC857C TR PBFREE	Central Semiconductor Corp	45	100	350	100	420	SOT-23	Active
BC857C,215	Nexperia USA Inc.	45	100	250	100	420	TO-236AB	Active
BC857CM,315	Nexperia USA Inc.	45	100	150	100	420	SOT-883	Active
BC857CMB,315	NXP Semiconductors	45	100	250	100	420	DFN1006B-3	Active
BC857CW,115	Nexperia USA Inc.	45	100	200	100	420	SOT-323	Active

Engineering Selection Recommendations

Direct Package Replacement (SC-75/SOT-416): BC857BTT1G and 2SA1774T1G provide direct footprint compatibility with the BC857CT,115. Both are active products with AEC-Q101 qualification available. BC857BTT1G maintains identical electrical specifications and is manufactured by onsemi with high inventory availability (118,200 pcs). The 2SA1774T1G offers enhanced voltage rating (50 V) and higher transition frequency (140 MHz) from onsemi, suitable for applications requiring additional performance margin.

Automotive-Grade Alternatives: BC857C,215 (Nexperia USA Inc.) and BC857CM,315 (Nexperia USA Inc.) both carry AEC-Q101 automotive qualification matching the original part's grade. BC857C,215 is available in TO-236AB package with 63,200 pcs in stock, while BC857CM,315 uses the ultra-compact SOT-883 package with 11,054 pcs available. Both maintain the 420 hFE specification and 45 V breakdown voltage of the original.

Compact Package Options: BC857CW,115 (SOT-323) and BC857BWT1G (SC-70) provide space-constrained board layout solutions while maintaining electrical compatibility. BC857CW,115 offers automotive qualification and 77,847 pcs inventory. BC857BWT1G provides 150 mW power rating identical to the original with 15,918 pcs available.

Enhanced Power Dissipation: BC857A-TP and BC857B-TP (Micro Commercial Co, SOT-23 package) offer 310 mW power rating with 200 MHz transition frequency, providing additional thermal and frequency margin. BC857C TR PBFREE (Central Semiconductor Corp) delivers 350 mW in SOT-23 package with 420 hFE matching the original specification.

Product Status Consideration: All recommended substitutes are active products with established supply chains. The BC857CT,115 obsolete status necessitates transition to one of these active alternatives to ensure long-term component availability and supply chain continuity.

Frequently Asked Questions (FAQ)

Q: Can BC857BTT1G directly replace BC857CT,115 without circuit modification? A: Yes. BC857BTT1G maintains identical electrical specifications (45 V, 100 mA, 100 MHz, 220 hFE @ 2mA, 5V) and uses the same SC-75 package footprint. Both are surface mount devices with compatible pinouts. No circuit redesign is required.

Q: What is the difference between BC857C,215 and BC857CM,315? A: Both are manufactured by Nexperia USA Inc. with identical electrical specifications and AEC-Q101 automotive qualification. The primary difference is package: BC857C,215 uses TO-236AB (SOT-23 footprint), while BC857CM,315 uses SOT-883 (ultra-compact). Selection depends on available board space and layout requirements.

Q: Why does 2SA1774T1G have lower hFE (120) compared to BC857CT,115 (420)? A: The 2SA1774T1G is a different device variant with different DC current gain characteristics. While hFE differs, it remains within acceptable ranges for general-purpose switching applications. Circuit designers must verify that the lower hFE does not impact bias point calculations or switching speed in their specific application.

Q: Are all substitute parts RoHS3 compliant? A: Yes. All listed substitute parts are RoHS3 compliant, matching the environmental compliance of the original BC857CT,115.

Q: Which substitute offers the best thermal performance? A: BC857A-TP and BC857B-TP (Micro Commercial Co) offer the highest power dissipation rating at 310 mW, followed by BC857C TR PBFREE at 350 mW. These are suitable for applications requiring enhanced thermal margin. Standard alternatives (BC857BTT1G, BC857CM,315, BC857CW,115, BC857BWT1G) maintain the original 150 mW rating.

Q: Can I use SOT-23 package substitutes if my PCB is designed for SC-75? A: No. SOT-23 and SC-75 packages have different footprints and pinout arrangements. PCB layout modification is required. However, electrical functionality remains equivalent. Consult package datasheets for pin correspondence before redesign.

Q: What is the inventory status for immediate procurement? A: BC857BTT1G offers the highest availability (118,200 pcs), followed by BC857CMB,315 (179,840 pcs in bulk). BC857C,215 provides 63,200 pcs in tape and reel format. All listed substitutes maintain active production status with established supply channels.

Q: Is automotive qualification required for my application? A: If your application requires AEC-Q101 automotive qualification, select BC857C,215, BC857CM,315, BC857CMB,315, or BC857CW,115. These parts carry explicit automotive grade designation. Standard industrial-grade alternatives (BC857A-TP, BC857B-TP, BC857BTT1G) do not carry automotive qualification.

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