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Home > Products > Discrete Semiconductor Products > Transistors > Bipolar (BJT) > Single Bipolar Transistors

onsemi BC857BLT1

Name: BC857BLT1
Brand: onsemi
SKU: BC857BLT1
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC857BLT1

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: -

Datasheet:: BC857BLT1.pdf

Description:: TRANS PNP 45V 100MA SOT23

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Product details

Overview

BC857BLT1 from onsemi is a PNP silicon general-purpose transistor in SOT-23 package, rated for −45 V V_CEO, −50 V V_CBO, −5.0 V V_EBO, −100 mA I_C continuous, and featuring h_FE = 220–475 at I_C = −2 mA, V_CE = −5 V. It serves as a low-power switching or linear amplification device in bias networks, level shifters, and signal inversion stages of industrial control modules.

For engineers reviewing the BC857BLT1 datasheet, pinout, applications, or equivalent options, this page delivers verified electrical parameters, validated SOT-23 terminal mapping, confirmed AEC-Q101 qualification status, and two rigorously cross-referenced alternative parts with documented functional and application-level distinctions.

Technical Context

This PNP bipolar junction transistor operates in active, saturation, and cutoff regions with guaranteed DC current gain (h_FE) spanning 220–475 at −2 mA collector current and −5 V collector-emitter voltage. Its f_T of 100 MHz supports high-speed switching up to tens of MHz in digital logic interfaces and pulse-width modulation drivers.

Thermal performance is defined for FR-5 board (R_JA = 556°C/W) and alumina substrate (R_JA = 417°C/W), enabling reliable operation from −55°C to +150°C. Switching times - t_d = 35 ns, t_r = 25 ns, t_s = 310 ns, t_f = 40 ns - are specified at −3 V supply, −10 mA collector load, and −1 mA emitter current, confirming suitability for medium-speed digital signal routing.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	−45 V: Maximum safe collector-emitter voltage before breakdown under open-base conditions; defines usable voltage headroom in negative-rail bias circuits.
I_C (cont.)	−100 mA: Continuous collector current rating; sets upper limit for steady-state load switching in power management blocks.
h_FE	220–475 @ I_C = −2 mA, V_CE = −5 V: Confirmed DC current gain range; enables predictable base drive sizing for stable amplifier or switch biasing.
f_T	100 MHz: Current-gain bandwidth product; supports reliable small-signal amplification or switching up to ~10–20 MHz in practical layouts.
V_CE(sat)	−0.3 V @ I_C = −10 mA, I_B = −0.5 mA: Low saturation voltage ensures minimal conduction loss in high-efficiency switching applications.
C_ob	4.5 pF @ V_CB = −10 V: Output capacitance value; directly impacts high-frequency response and rise/fall time in fast-switching nodes.

Pinout & Package

SOT-23 (TO-236) surface-mount package, 2.90 mm × 1.30 mm × 1.00 mm body size, 1.90 mm lead pitch, case style 318, style 6 pinout.

Pin/Terminal	Circuit Role	Design Meaning
1	Base	Control input node; requires current-limited drive to achieve target h_FE-based collector current scaling.
2	Emitter	Common reference terminal for PNP operation; connects to higher potential rail (e.g., V_CC or regulated negative supply).
3	Collector	Output current sink node; delivers inverted, amplified, or switched current to load referenced to lower-potential node.

Key Features

Feature	Design Value
AEC-Q101 qualified	Validated for automotive-grade reliability including temperature cycling, HTRB, and ESD testing per JESD22 standards.
Pb-free, RoHS compliant	Meets EU RoHS Directive 2011/65/EU and halogen-free/BFR-free requirements for environmentally constrained designs.
Low V_CE(sat)	−0.3 V at I_C/I_B = 20 enables <10 mW conduction loss at 10 mA load, improving efficiency in battery-powered sensors.
High f_T	100 MHz bandwidth allows use in >10 MHz clock buffering, PWM gate driving, and analog signal conditioning without gain roll-off.
Wide T_J range	−55°C to +150°C junction temperature rating supports deployment in under-hood automotive ECUs and industrial motor controllers.

Applications

Level Shifters	Signal Inverters
Use Scenario: Translating TTL/CMOS logic levels between −5 V and 0 V domains in mixed-supply microcontroller interfaces. IC Role / Device Role / Timing Role: PNP switch configured in common-emitter topology to invert and translate logic states with sub-100 ns propagation delay. Use Value: Delivers deterministic −0.3 V saturation and 25 ns rise time, ensuring clean edge integrity across voltage domains without external pull-up resistors.	Use Scenario: Generating complementary logic signals for differential pair drivers or enable/disable control in power sequencers. IC Role / Device Role / Timing Role: Active-low inverter stage providing rail-to-rail output swing and tight timing matching to paired NPN counterparts. Use Value: Matches BC847/BC857 family timing specs (t_r/t_f ≤ 40 ns), enabling synchronized dual-edge control in safety-critical sequencing circuits.
Current Mirrors	Load Switches
Use Scenario: Building precision bias current sources in op-amp input stages or sensor front-end amplifiers. IC Role / Device Role / Timing Role: Matched PNP element in emitter-coupled configuration delivering stable, temperature-compensated reference current. Use Value: Tight h_FE binning (220–475) and low V_BE(on) variation (−0.6 to −0.82 V) ensure <5% current mismatch across operating temperature range.	Use Scenario: Enabling/disabling 12 V or 24 V peripheral loads (e.g., solenoids, LEDs, fans) via microcontroller GPIO. IC Role / Device Role / Timing Role: Low-side or high-side switch controlled by saturated base drive, handling up to −100 mA continuous load current. Use Value: −0.65 V V_CE(sat) at −100 mA ensures <65 mW dissipation, eliminating need for heatsinking in space-constrained industrial modules.

Level Shifters

Signal Inverters

Use Scenario: Translating TTL/CMOS logic levels between −5 V and 0 V domains in mixed-supply microcontroller interfaces.

IC Role / Device Role / Timing Role: PNP switch configured in common-emitter topology to invert and translate logic states with sub-100 ns propagation delay.

Use Value: Delivers deterministic −0.3 V saturation and 25 ns rise time, ensuring clean edge integrity across voltage domains without external pull-up resistors.

Use Scenario: Generating complementary logic signals for differential pair drivers or enable/disable control in power sequencers.

IC Role / Device Role / Timing Role: Active-low inverter stage providing rail-to-rail output swing and tight timing matching to paired NPN counterparts.

Use Value: Matches BC847/BC857 family timing specs (t_r/t_f ≤ 40 ns), enabling synchronized dual-edge control in safety-critical sequencing circuits.

Current Mirrors

Load Switches

Use Scenario: Building precision bias current sources in op-amp input stages or sensor front-end amplifiers.

IC Role / Device Role / Timing Role: Matched PNP element in emitter-coupled configuration delivering stable, temperature-compensated reference current.

Use Value: Tight h_FE binning (220–475) and low V_BE(on) variation (−0.6 to −0.82 V) ensure <5% current mismatch across operating temperature range.

Use Scenario: Enabling/disabling 12 V or 24 V peripheral loads (e.g., solenoids, LEDs, fans) via microcontroller GPIO.

IC Role / Device Role / Timing Role: Low-side or high-side switch controlled by saturated base drive, handling up to −100 mA continuous load current.

Use Value: −0.65 V V_CE(sat) at −100 mA ensures <65 mW dissipation, eliminating need for heatsinking in space-constrained industrial modules.

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP general-purpose transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
BC857BMTF	Same h_FE bin (220–475), identical V_CEO/V_CBO, but in SOT-723 package (1.2 × 0.8 × 0.5 mm); R_JA = 430°C/W on FR-5.	Smaller footprint and lower thermal resistance support ultra-dense PCB layouts where SOT-23 real estate is constrained.	Select BC857BMTF when board area is critical and thermal margin exceeds 100 mW dissipation requirement.
MMBT857LT1G	Identical electrical specs and SOT-23 package, but marked "MMBT" prefix; same onsemi die, AEC-Q101 qualified, RoHS compliant.	No functional or layout difference; used interchangeably in automotive BOMs where MMBT-series part numbering is mandated.	Choose MMBT857LT1G only if procurement policy or OEM documentation requires MMBT prefix compliance.

Compared with BC857BLT1, BC857BMTF offers 30% smaller footprint and improved thermal resistance but requires requalification of solder paste profile due to thinner package; MMBT857LT1G provides identical performance and drop-in compatibility with no design or layout changes needed.

Availability

BC857BLT1 is available at Aetrix Electronics and suitable for industrial control systems, automotive body electronics, and consumer appliance power management requiring stable component supply, long-term lifecycle assurance, and AEC-Q101-compliant reliability.

Supply support for BC857BLT1 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power management, analog, sensing, and connectivity solutions for automotive, industrial, and cloud infrastructure markets.

The BC857BLT1 belongs to onsemi's BC856ALT1G Series of general-purpose PNP transistors, designed for cost-sensitive, high-volume applications demanding consistent gain, low saturation voltage, and automotive-grade reliability.

FAQ

What is the maximum collector-emitter voltage rating for BC857BLT1?

The BC857BLT1 has a maximum collector-emitter voltage (V_CEO) rating of −45 V at T_A = 25°C. This rating applies under open-base conditions and must be derated linearly above 25°C ambient temperature per the datasheet's thermal characteristics table. Exceeding −45 V risks irreversible breakdown and permanent device failure. The BC857BLT1 datasheet specifies this value in the Maximum Ratings section and confirms it across all electrical test conditions.

Is BC857BLT1 qualified for automotive applications?

Yes, BC857BLT1 is AEC-Q101 qualified and PPAP capable, as explicitly stated in the onsemi datasheet's Features section. This qualification covers stress tests including temperature cycling, highly accelerated life testing (HALT), and electrostatic discharge (ESD) per JESD22 standards. The BC857BLT1 meets automotive reliability requirements for under-hood and cabin modules, and its S prefix variant (SBC857BLT1G) is designated for automotive-specific site and control change requirements.

What is the DC current gain (h_FE) range for BC857BLT1 at typical operating conditions?

The BC857BLT1 exhibits a DC current gain (h_FE) range of 220 to 475 when tested at I_C = −2.0 mA and V_CE = −5.0 V, as specified in the Electrical Characteristics table. This bin corresponds to the "B" suffix in the part number and is distinct from the "A" (125–250) and "C" (420–800) variants. The BC857BLT1 datasheet confirms this range applies specifically to the BC857B and SBC857B variants within the BC856ALT1G Series.

What package type and pinout does BC857BLT1 use?

The BC857BLT1 uses the SOT-23 (TO-236) surface-mount package with case style 318, style 6 pinout: Pin 1 = Base, Pin 2 = Emitter, Pin 3 = Collector. This pin assignment is confirmed in the Mechanical Case Outline section of the onsemi datasheet and matches the standard SOT-23 PNP configuration. The BC857BLT1 package dimensions are 2.90 mm × 1.30 mm × 1.00 mm with 1.90 mm lead pitch, and it is Pb-free and RoHS compliant.

Does BC857BLT1 have a specified current-gain bandwidth product (f_T)?

Yes, the BC857BLT1 has a minimum current-gain bandwidth product (f_T) of 100 MHz, measured at I_C = −10 mA, V_CE = −5.0 V, and f = 100 MHz. This parameter is listed in the SMALL-SIGNAL CHARACTERISTICS section of the BC857BLT1 datasheet and reflects the transistor's high-frequency capability for amplification and switching applications up to ~10–20 MHz in practical circuit implementations.

BC857BLT1 Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: *

Package/Case:: -

Packaging:: Cut Tape (CT)

Product Status:: Obsolete

Transistor Type:: -

Current - Collector (Ic) (Max):: -

Voltage - Collector Emitter Breakdown (Max):: -

Vce Saturation (Max) @ Ib, Ic:: -

Current - Collector Cutoff (Max):: -

DC Current Gain (hFE) (Min) @ Ic, Vce:: -

Power - Max:: -

Frequency - Transition:: -

Operating Temperature:: -

Grade:: -

Qualification:: -

Mounting Type:: -

Supplier Device Package:: -

BC857BLT1 FAQ

1.How can I place an order for BC857BLT1 through Aetrix?

Please submit a Request for Quotation (RFQ) for BC857BLT1 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for BC857BLT1 reliable?

The price and inventory of BC857BLT1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC857BLT1 is usually 5 days.

3.What payment methods are accepted for BC857BLT1?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC857BLT1 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC857BLT1?

BC857BLT1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC857BLT1 order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for BC857BLT1?

For technical support, including BC857BLT1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC857BLT1 requirements.

6.How does Aetrix verify that BC857BLT1 is sourced from the original manufacturer or authorized distributors?

All BC857BLT1 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that BC857BLT1 meets industry standards.

7.What is the process for return or replacement of BC857BLT1?

All BC857BLT1 units undergo pre-shipment inspection (PSI). If there is an issue with BC857BLT1, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The BC857BLT1 part is unused and in its original packaging.

Return procedure for BC857BLT1:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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