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

onsemi BC859BLT1G

Name: BC859BLT1G
Brand: onsemi
SKU: BC859BLT1G
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC859BLT1G

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-236-3, SC-59, SOT-23-3

Datasheet:: BC859BLT1G.pdf

Description:: TRANS PNP 30V 0.1A SOT23-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BC859BLT1G from onsemi is a PNP silicon general-purpose transistor in SOT-23 package, rated for V_CEO = −30 V, I_C = −100 mA continuous, and h_FE = 220–475 (at I_C = −2 mA, V_CE = −5 V). It delivers low V_CE(sat) of −0.3 V (I_C = −10 mA, I_B = −0.5 mA) and f_T = 100 MHz, enabling use in compact DC amplification and switching circuits in power management subsystems.

For engineers reviewing the BC859BLT1G datasheet, pinout, applications, or equivalent options, key selection considerations include its −30 V V_CEO, SOT-23 footprint compatibility, AEC-Q101 qualification for automotive-grade reliability, and verified noise figure of 4.0 dB at 1 kHz - critical for low-noise biasing and signal conditioning stages.

Technical Context

This PNP bipolar junction transistor operates in active, saturation, and cutoff regions with defined safe operating area (SOA) limits up to −100 mA and −45 V under pulsed conditions. Its base-emitter junction exhibits a temperature coefficient of −2.2 mV/°C and V_BE(on) = −0.75 V at I_C = −10 mA, supporting stable bias design across −55°C to +150°C.

Small-signal behavior is characterized by C_ob = 4.5 pF at V_CB = −10 V and f_T = 100 MHz, confirming suitability for audio-frequency amplification and moderate-speed switching (t_r = 25 ns, t_f = 40 ns). The device meets Pb-free, RoHS, and halogen-free requirements per onsemi's manufacturing standards.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	−30 V - Maximum collector-emitter voltage before breakdown; defines safe DC rail headroom in PNP switch or amplifier stages
I_C Continuous	−100 mA - Continuous collector current rating; sets upper limit for steady-state load driving capability
h_FE	220–475 - DC current gain range at I_C = −2 mA; enables predictable base drive sizing for switching or linear operation
V_CE(sat)	−0.3 V (I_C/I_B = 20) - Low saturation voltage minimizes conduction loss in high-efficiency PNP switch applications
f_T	100 MHz - Unity-gain frequency confirms usable bandwidth for audio and low-MHz signal amplification
NF	4.0 dB @ 1 kHz - Verified noise figure supports low-noise preamplifier and sensor interface designs
R_JA	556 °C/W (FR-5 board) - Thermal resistance informs heatsinking needs for sustained 100 mA operation

Pinout & Package

SOT-23 (TO-236) surface-mount package, 2.90 mm × 1.30 mm × 1.00 mm body, 1.90 mm lead pitch. RoHS-compliant, Pb-free construction.

Pin/Terminal	Circuit Role	Design Meaning
1	Base	Control terminal; requires current-limited drive to achieve specified h_FE and switching speed
2	Emitter	Current source terminal; connected to higher potential rail in PNP configuration
3	Collector	Output terminal; sinks current to load when biased on; polarity must match PNP topology

Key Features

Feature	Design Value
AEC-Q101 qualified	Validated for automotive applications including engine control modules and body electronics requiring extended temperature and reliability compliance
V_CEO = −30 V	Enables direct replacement of legacy BC559 in 24 V industrial control systems without derating
Low V_CE(sat)	Reduces power dissipation below 3 mW at 10 mA load, improving thermal margin in dense PCB layouts
4.0 dB noise figure	Supports precision analog front-ends in sensor signal chains where emitter-follower buffering is required
SOT-23 footprint	Ensures drop-in compatibility with existing pick-and-place tooling and reflow profiles used for BC846–BC859 family

Applications

LED Driver Circuit	Level-Shifting Interface
Use Scenario: Driving 20 mA indicator LEDs from 3.3 V microcontroller GPIO pins in automotive dashboards. IC Role / Device Role / Timing Role: PNP switch controlling LED anode connection to 5 V rail; base driven by inverted logic signal. Use Value: V_CE(sat) ≤ −0.3 V ensures <10 mW dissipation per LED channel, eliminating need for external heat sinking in space-constrained clusters.	Use Scenario: Translating 1.8 V logic outputs to 5 V domains in mixed-voltage MCU peripherals. IC Role / Device Role / Timing Role: Emitter-follower level shifter with grounded emitter, base driven by low-V_OH source. Use Value: h_FE ≥ 220 guarantees sufficient current sourcing into 10 kΩ pull-up loads while maintaining <100 ns propagation delay.
Low-Noise Sensor Bias	Power Supply Enable Switch
Use Scenario: Providing stable bias current to piezoresistive pressure sensor bridges in medical instrumentation. IC Role / Device Role / Timing Role: Constant-current source configured with emitter resistor; operates in active region with minimal thermal drift. Use Value: NF = 4.0 dB and −2.2 mV/°C V_BE TC enable sub-μV output drift over 0–50°C ambient range.	Use Scenario: Enabling/disabling 12 V auxiliary rails in industrial PLC I/O modules via microcontroller command. IC Role / Device Role / Timing Role: High-side switch controlling PMOS gate drive or directly sourcing load current up to 100 mA. Use Value: −30 V V_CEO and −100 mA I_C rating allow direct control of 12 V/100 mA loads without external driver staging.

LED Driver Circuit

Level-Shifting Interface

Use Scenario: Driving 20 mA indicator LEDs from 3.3 V microcontroller GPIO pins in automotive dashboards.

IC Role / Device Role / Timing Role: PNP switch controlling LED anode connection to 5 V rail; base driven by inverted logic signal.

Use Value: V_CE(sat) ≤ −0.3 V ensures <10 mW dissipation per LED channel, eliminating need for external heat sinking in space-constrained clusters.

Use Scenario: Translating 1.8 V logic outputs to 5 V domains in mixed-voltage MCU peripherals.

IC Role / Device Role / Timing Role: Emitter-follower level shifter with grounded emitter, base driven by low-V_OH source.

Use Value: h_FE ≥ 220 guarantees sufficient current sourcing into 10 kΩ pull-up loads while maintaining <100 ns propagation delay.

Low-Noise Sensor Bias

Power Supply Enable Switch

Use Scenario: Providing stable bias current to piezoresistive pressure sensor bridges in medical instrumentation.

IC Role / Device Role / Timing Role: Constant-current source configured with emitter resistor; operates in active region with minimal thermal drift.

Use Value: NF = 4.0 dB and −2.2 mV/°C V_BE TC enable sub-μV output drift over 0–50°C ambient range.

Use Scenario: Enabling/disabling 12 V auxiliary rails in industrial PLC I/O modules via microcontroller command.

IC Role / Device Role / Timing Role: High-side switch controlling PMOS gate drive or directly sourcing load current up to 100 mA.

Use Value: −30 V V_CEO and −100 mA I_C rating allow direct control of 12 V/100 mA loads without external driver staging.

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
BC859CLT1G	Higher h_FE (420–800), same V_CEO/I_C ratings and SOT-23 package	Better suited for low-base-drive applications like battery-powered sensor nodes	Select when minimizing base current is critical and tighter h_FE tolerance is acceptable
MMBT3906LT1G	Same V_CEO (−40 V), lower h_FE (100–300), identical SOT-23 footprint and pinout	Widely available alternative with broader distributor stock but less gain consistency	Choose for cost-sensitive designs where gain variation ≤3× is tolerable and AEC-Q101 is not required

Compared with BC859BLT1G, BC859CLT1G offers higher gain for ultra-low-drive scenarios, while MMBT3906LT1G provides broader supply-chain availability at the expense of AEC-Q101 qualification and tighter h_FE distribution - making BC859BLT1G optimal for automotive-qualified, gain-stable PNP switching.

Availability

BC859BLT1G is available at Aetrix Electronics and suitable for automotive body control modules, industrial sensor interfaces, and consumer power management systems requiring stable component supply, long-term lifecycle support, and AEC-Q101 compliance.

Supply support for BC859BLT1G 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, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and IoT markets.

The BC859BLT1G belongs to onsemi's BC856ALT1G Series of general-purpose PNP transistors, designed specifically for high-reliability, space-constrained switching and amplification in automotive and industrial control applications.

FAQ

What is the maximum collector-emitter voltage rating for BC859BLT1G?

The BC859BLT1G has a maximum collector-emitter voltage (V_CEO) rating of −30 V at T_A = 25°C. This rating applies under standard test conditions with I_C = −10 mA and defines the absolute maximum reverse-biased voltage the transistor can withstand before breakdown. Exceeding this value risks permanent damage and is not recommended in any design using BC859BLT1G.

Is BC859BLT1G suitable for automotive applications?

Yes, BC859BLT1G is AEC-Q101 qualified and PPAP capable, making it suitable for automotive applications including body electronics, lighting control, and power distribution modules. Its guaranteed operation from −55°C to +150°C, Pb-free/RoHS compliance, and validated reliability testing per AEC-Q101 ensure robust performance in vehicle environments where BC859BLT1G is deployed.

What is the DC current gain (h_FE) range for BC859BLT1G?

The BC859BLT1G 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. This gain bin ('B' suffix) is confirmed in the official onsemi datasheet and distinguishes BC859BLT1G from 'A' (125–250) and 'C' (420–800) variants within the same family.

Does BC859BLT1G have the same pinout as other SOT-23 PNP transistors?

Yes, BC859BLT1G uses Style 6 pinout per onsemi's mechanical drawings: Pin 1 = Base, Pin 2 = Emitter, Pin 3 = Collector. This matches industry-standard SOT-23 PNP configurations including MMBT3906LT1G and BC857BLT1G, enabling layout reuse and simplified PCB design when BC859BLT1G is substituted within compatible gain/voltage classes.

What is the thermal resistance (R_JA) of BC859BLT1G on FR-5 board?

The BC859BLT1G has a junction-to-ambient thermal resistance (R_JA) of 556°C/W when mounted on a standard FR-5 PCB (1.0 × 0.75 × 0.062 in) at T_A = 25°C. This value is critical for calculating junction temperature rise under load and confirms that BC859BLT1G can dissipate up to 225 mW continuously before exceeding its 150°C maximum junction temperature limit.

BC859BLT1G Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-236-3, SC-59, SOT-23-3

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Transistor Type:: PNP

Current - Collector (Ic) (Max):: 100 mA

Voltage - Collector Emitter Breakdown (Max):: 30 V

Vce Saturation (Max) @ Ib, Ic:: 650mV @ 5mA, 100mA

Current - Collector Cutoff (Max):: 15nA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 220 @ 2mA, 5V

Power - Max:: 300 mW

Frequency - Transition:: 100MHz

Operating Temperature:: -55°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-23-3 (TO-236)

BC859BLT1G FAQ

1.How can I place an order for BC859BLT1G through Aetrix?

Please submit a Request for Quotation (RFQ) for BC859BLT1G 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 BC859BLT1G reliable?

The price and inventory of BC859BLT1G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC859BLT1G is usually 5 days.

3.What payment methods are accepted for BC859BLT1G?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC859BLT1G transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC859BLT1G?

BC859BLT1G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC859BLT1G 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 BC859BLT1G?

For technical support, including BC859BLT1G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC859BLT1G requirements.

6.How does Aetrix verify that BC859BLT1G is sourced from the original manufacturer or authorized distributors?

All BC859BLT1G 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 BC859BLT1G meets industry standards.

7.What is the process for return or replacement of BC859BLT1G?

All BC859BLT1G units undergo pre-shipment inspection (PSI). If there is an issue with BC859BLT1G, 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 BC859BLT1G part is unused and in its original packaging.

Return procedure for BC859BLT1G:

1.Submit a request within 90 days.

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

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