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

onsemi BC859BLT1

Name: BC859BLT1
Brand: onsemi
SKU: BC859BLT1
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC859BLT1

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: BC859BLT1.pdf

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

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BC859BLT1 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) = −0.3 V (at I_C = −10 mA, I_B = −0.5 mA) and f_T = 100 MHz, supporting switching and linear amplification in compact power management circuits.

For engineers reviewing the BC859BLT1 datasheet, pinout, applications, or equivalent options, key selection criteria include its −30 V V_CEO, SOT-23 footprint compatibility, AEC-Q101 qualification status, noise figure of 4.0 dB (at I_C = −0.2 mA), and guaranteed h_FE binning (B grade).

Technical Context

The BC859BLT1 operates as a discrete PNP bipolar junction transistor optimized for medium-speed switching and analog amplification. Its DC current gain (h_FE) is binned to 220–475 at −2 mA collector current, with saturation voltage tightly specified at −0.3 V under standard test conditions.

Thermal performance is defined for FR-5 board (R_JA = 556 °C/W) and alumina substrate (R_JA = 417 °C/W), supporting reliable operation from −55 °C to +150 °C. Switching times are characterized at −3 V supply: t_d = 35 ns, t_r = 25 ns, t_s = 310 ns, t_f = 40 ns.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	−30 V - Maximum safe collector-emitter voltage before breakdown in open-base configuration
I_C (continuous)	−100 mA - Continuous collector current limit defining steady-state power handling capability
h_FE (B grade)	220–475 - Confirmed DC current gain range at −2 mA I_C, enabling predictable bias design
V_CE(sat)	−0.3 V @ −10 mA I_C, −0.5 mA I_B - Low saturation voltage reduces conduction loss in switch applications
f_T	100 MHz - Transition frequency confirming suitability for audio and low-MHz signal amplification
NF	4.0 dB @ −0.2 mA I_C - Measured noise figure supporting low-noise preamplifier stages
P_D (FR-5)	225 mW - Maximum dissipation on standard PCB, derated by 1.8 mW/°C above 25 °C

Pinout & Package

SOT-23 (TO-236) surface-mount package, 2.90 × 1.30 × 1.00 mm, 3-pin, Pb-free and RoHS compliant.

Pin/Terminal	Circuit Role	Design Meaning
1	Base	Control terminal for forward-biased PNP operation; requires negative base current relative to emitter
2	Emitter	Current source terminal; connected to higher potential in PNP circuit topology
3	Collector	Current sink terminal; output node where load is typically connected to ground or lower potential

Key Features

Feature	Design Value
AEC-Q101 qualified	Validated for automotive-grade reliability including temperature cycling, HTRB, and ESD testing per JESD47
h_FE binned (B grade)	Guaranteed 220–475 gain range enables consistent bias point setting without post-layout trimming
Low V_CE(sat)	−0.3 V ensures <10 mW conduction loss at 10 mA, critical for battery-powered load switches
100 MHz f_T	Supports stable small-signal amplification up to mid-audio frequencies with minimal phase shift
−55 °C to +150 °C T_J	Extended junction temperature range allows deployment in under-hood or industrial ambient environments

Applications

LED Driver Circuit	Level-Shifting Interface
Use Scenario: Driving 20 mA indicator LEDs from 3.3 V microcontroller GPIO pins with inverted logic. IC Role / Device Role / Timing Role: PNP switch controlling LED anode connection to supply rail; turns ON when GPIO is LOW. Use Value: −0.3 V V_CE(sat) minimizes voltage drop across transistor, preserving >2.7 V for LED forward bias at full current.	Use Scenario: Translating 1.8 V logic signals to 5 V domains in mixed-voltage MCU systems. IC Role / Device Role / Timing Role: Active-low level shifter using emitter-follower configuration with pull-up resistor. Use Value: 100 MHz f_T and 4.0 dB NF ensure clean edge integrity and low added noise during voltage translation.
Current Mirror Reference	Power Supply Enable Switch
Use Scenario: Building matched current sources in precision analog sensor conditioning circuits. IC Role / Device Role / Timing Role: PNP element in two-transistor mirror topology, leveraging tight h_FE binning for ratio accuracy. Use Value: 220–475 h_FE range and −5.0 V V_EBO allow stable base-emitter biasing without excessive base current error.	Use Scenario: Enabling/disabling 3.3 V subsystem rails via microcontroller-controlled high-side switch. IC Role / Device Role / Timing Role: High-side PNP pass device with base driven through current-limiting resistor. Use Value: −30 V V_CEO provides 2× margin over 12 V input transients, ensuring robustness in industrial power sequencing.

LED Driver Circuit

Level-Shifting Interface

Use Scenario: Driving 20 mA indicator LEDs from 3.3 V microcontroller GPIO pins with inverted logic.

IC Role / Device Role / Timing Role: PNP switch controlling LED anode connection to supply rail; turns ON when GPIO is LOW.

Use Value: −0.3 V V_CE(sat) minimizes voltage drop across transistor, preserving >2.7 V for LED forward bias at full current.

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

IC Role / Device Role / Timing Role: Active-low level shifter using emitter-follower configuration with pull-up resistor.

Use Value: 100 MHz f_T and 4.0 dB NF ensure clean edge integrity and low added noise during voltage translation.

Current Mirror Reference

Power Supply Enable Switch

Use Scenario: Building matched current sources in precision analog sensor conditioning circuits.

IC Role / Device Role / Timing Role: PNP element in two-transistor mirror topology, leveraging tight h_FE binning for ratio accuracy.

Use Value: 220–475 h_FE range and −5.0 V V_EBO allow stable base-emitter biasing without excessive base current error.

Use Scenario: Enabling/disabling 3.3 V subsystem rails via microcontroller-controlled high-side switch.

IC Role / Device Role / Timing Role: High-side PNP pass device with base driven through current-limiting resistor.

Use Value: −30 V V_CEO provides 2× margin over 12 V input transients, ensuring robustness in industrial power sequencing.

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
BC857BLT1G	V_CEO = −45 V, V_CBO = −50 V, h_FE = 220–475 (same B grade), same SOT-23 package	Higher voltage rating supports 24 V system interfaces; identical pinout and gain binning	Select when operating beyond 30 V collector-emitter stress or requiring higher breakdown margin
BC859CLT1G	h_FE = 420–800 (C grade), same V_CEO/V_CBO/package, V_CE(sat) = −0.3 V (typ)	Higher gain enables reduced base drive current; same thermal and switching specs	Choose for low-drive applications like high-impedance sensor buffers where base current must be minimized

Compared with BC857BLT1G, BC859BLT1 offers lower voltage rating but identical gain and saturation behavior; compared with BC859CLT1G, it trades higher h_FE for tighter gain tolerance control-critical where predictable bias stability outweighs maximum gain.

Availability

BC859BLT1 is available at Aetrix Electronics and suitable for LED driver circuits, level-shifting interfaces, current mirror references, and power supply enable switches requiring stable component supply, automotive-grade reliability, and SOT-23 footprint consistency.

Supply support for BC859BLT1 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 is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.

The BC859BLT1 belongs to onsemi's BC856ALT1G Series of general-purpose PNP transistors, designed for cost-sensitive, space-constrained switching and amplification tasks in consumer, industrial, and automotive electronics.

FAQ

What is the maximum collector-emitter voltage rating for BC859BLT1?

The BC859BLT1 has a maximum collector-emitter voltage (V_CEO) rating of −30 V at T_A = 25 °C. This rating applies under open-base conditions and defines the upper limit for safe DC or peak repetitive voltage across the collector and emitter terminals. Exceeding this value risks irreversible breakdown. The BC859BLT1 datasheet confirms this parameter in both Maximum Ratings and Electrical Characteristics tables.

Is BC859BLT1 suitable for automotive applications?

Yes, BC859BLT1 is AEC-Q101 qualified and PPAP capable, meeting the stress test requirements for automotive electronics including temperature cycling, highly accelerated life testing (HALT), and electrostatic discharge (ESD) per JESD47. Its −55 °C to +150 °C junction temperature range and Pb-free, RoHS-compliant SOT-23 package make it appropriate for under-dash, body control, and lighting modules where reliability under thermal and vibration stress is mandatory. The BC859BLT1 datasheet explicitly lists AEC-Q101 qualification in its Features section.

What is the h_FE range for BC859BLT1 and how is it tested?

The BC859BLT1 is binned to the "B" gain grade, with a guaranteed h_FE range of 220 to 475 at I_C = −2.0 mA and V_CE = −5.0 V, measured at T_A = 25 °C. This specification is verified per the Electrical Characteristics table in the official onsemi datasheet. The binning ensures consistent DC current gain across production lots, reducing need for circuit-level gain compensation in production designs using BC859BLT1.

Does BC859BLT1 have a specified noise figure, and under what conditions?

Yes, BC859BLT1 has a specified noise figure (NF) of 4.0 dB, measured at I_C = −0.2 mA, V_CE = −5.0 V, R_S = 2.0 kΩ, f = 1.0 kHz, and BW = 200 Hz. This value appears in the Electrical Characteristics table under SMALL-SIGNAL CHARACTERISTICS and reflects the transistor's contribution to signal degradation in low-level analog amplification stages-making BC859BLT1 suitable for microphone preamps or sensor front-ends where noise performance matters.

What is the thermal resistance of BC859BLT1 on FR-5 board?

The BC859BLT1 has a thermal resistance from junction-to-ambient (R_JA) of 556 °C/W when mounted on an FR-5 board (1.0 × 0.75 × 0.062 in), with a total device dissipation (P_D) of 225 mW at T_A = 25 °C. Derating is 1.8 mW/°C above 25 °C. These values are confirmed in the THERMAL CHARACTERISTICS section of the BC859BLT1 datasheet and define the maximum power the device can safely dissipate without exceeding its 150 °C maximum junction temperature.

BC859BLT1 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)

BC859BLT1 FAQ

1.How can I place an order for BC859BLT1 through Aetrix?

Please submit a Request for Quotation (RFQ) for BC859BLT1 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 BC859BLT1 reliable?

The price and inventory of BC859BLT1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC859BLT1 is usually 5 days.

3.What payment methods are accepted for BC859BLT1?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC859BLT1 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC859BLT1?

BC859BLT1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC859BLT1 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 BC859BLT1?

For technical support, including BC859BLT1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC859BLT1 requirements.

6.How does Aetrix verify that BC859BLT1 is sourced from the original manufacturer or authorized distributors?

All BC859BLT1 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 BC859BLT1 meets industry standards.

7.What is the process for return or replacement of BC859BLT1?

All BC859BLT1 units undergo pre-shipment inspection (PSI). If there is an issue with BC859BLT1, 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 BC859BLT1 part is unused and in its original packaging.

Return procedure for BC859BLT1:

1.Submit a request within 90 days.

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

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