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

onsemi BC559CBU

Name: BC559CBU
Brand: onsemi
SKU: BC559CBU
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC559CBU

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-226-3, TO-92-3 (TO-226AA)

Datasheet:: BC559CBU.pdf

Description:: TRANS PNP 30V 0.1A TO-92-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BC559CBU from onsemi is a PNP epitaxial silicon transistor optimized for low-noise amplification and general-purpose switching, with V_CEO = −30 V, h_FE = 420–800 (Class C), f_T = 150 MHz, and V_BE(on) = −600 to −750 mV at I_C = −2 mA - used in audio preamplifier stages and signal conditioning circuits where noise performance and gain stability are critical.

For engineers reviewing the BC559CBU datasheet, pinout, applications, or equivalent options, key selection criteria include its Class C h_FE range, low-noise figure (1.2–4.0 dB at 30–15 kHz), TO-92-3 package compatibility, and complementarity to BC549/BC550 NPN devices in push-pull amplifier designs.

Technical Context

The BC559CBU operates as a medium-gain, low-noise PNP bipolar junction transistor with fixed-emitter biasing capability and DC current gain controlled by h_FE classification (C = 420–800). Its thermal resistance R_JA = 250 °C/W enables operation up to T_J = 150 °C under defined PCB layout conditions.

It supports linear amplification with V_CE(sat) = −250 to −650 mV at I_C = −100 mA/I_B = −5 mA and exhibits Cob = 6 pF at V_CB = −10 V, making it suitable for audio-frequency small-signal amplification and low-speed switching below 150 MHz.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	−30 V - maximum collector-emitter voltage before breakdown; defines safe operating range in common-emitter amplifier configurations
h_FE (Class C)	420–800 - high DC current gain enabling low-base-drive requirements in amplifier and switch driver stages
f_T	150 MHz - usable bandwidth limit for small-signal amplification up to mid-VHF frequencies
Noise Figure	1.2–4.0 dB (30–15 kHz) - confirms suitability for low-noise audio preamplifier input stages
P_D	500 mW - total power dissipation at 25°C ambient; derates 4.0 mW/°C above that temperature
C_ob	6 pF - output capacitance limiting high-frequency response and affecting stability in tuned circuits
V_BE(on)	−600 to −750 mV @ I_C = −2 mA - base-emitter turn-on threshold defining bias network design margins

Pinout & Package

BC559CBU is housed in a TO-92-3 plastic package (Case 135AR), with leads formed for through-hole mounting. Dimensions: 4.83 mm × 4.76 mm × 4.0 mm.

Pin/Terminal	Circuit Role	Design Meaning
1 (Top View, Flat Side Up)	Collector	Main current sink terminal; connects to load or supply rail in common-emitter configuration
2	Base	Control input; requires current-limited drive to set operating point within h_FE-dependent I_C/I_B ratio
3	Emitter	Current source terminal; typically tied to ground or positive rail depending on circuit topology

Key Features

Feature	Design Value
Low-noise amplification	1.2–4.0 dB NF at audio band (30–15 kHz), enabling high-fidelity preamp stages without added filtering
High h_FE Class C	420–800 gain range reduces base drive current requirements and improves efficiency in linear and switching modes
Complementary pairing	Designed as direct PNP counterpart to BC549/BC550 NPN transistors for matched push-pull and differential pair implementations
Pb-free, RoHS-compliant	Meets EU Directive 2011/65/EU and halogen-free/BFR-free requirements for industrial and consumer end equipment

Applications

Audio Preamp Stage	Signal Level Shifting
Use Scenario: Amplifying weak microphone or piezoelectric sensor outputs in battery-powered portable recorders. IC Role / Device Role / Timing Role: Small-signal PNP amplifier providing voltage gain and impedance transformation in first-stage amplification. Use Value: Low 1.2–4.0 dB noise figure preserves signal integrity while Class C h_FE ensures stable gain across temperature without excessive base bias current.	Use Scenario: Converting logic-level signals from microcontrollers to higher-voltage analog control lines in mixed-signal instrumentation. IC Role / Device Role / Timing Role: Active level shifter using emitter-follower or common-emitter topology to invert and scale voltage levels. Use Value: V_CEO = −30 V and V_BE(on) = −600 to −750 mV enable reliable operation with ±12 V rails and predictable turn-on behavior.
Discrete Oscillator Core	LED Driver Switch
Use Scenario: Building low-frequency relaxation oscillators in timing circuits for blinkers or pulse generators. IC Role / Device Role / Timing Role: Active gain element in RC-timed feedback loop, leveraging h_FE stability and low C_ob for predictable frequency drift. Use Value: 6 pF Cob minimizes parasitic phase shift, while 150 MHz f_T ensures sufficient gain margin well above target oscillation frequencies (<1 MHz).	Use Scenario: Driving indicator LEDs in automotive dashboard modules requiring robust on/off control under varying supply conditions. IC Role / Device Role / Timing Role: Saturated switch controlling LED anode connection to regulated supply via collector-emitter path. Use Value: V_CE(sat) = −250 to −650 mV at I_C = −100 mA ensures minimal power loss and heat generation during continuous conduction.

Audio Preamp Stage

Signal Level Shifting

Use Scenario: Amplifying weak microphone or piezoelectric sensor outputs in battery-powered portable recorders.

IC Role / Device Role / Timing Role: Small-signal PNP amplifier providing voltage gain and impedance transformation in first-stage amplification.

Use Value: Low 1.2–4.0 dB noise figure preserves signal integrity while Class C h_FE ensures stable gain across temperature without excessive base bias current.

Use Scenario: Converting logic-level signals from microcontrollers to higher-voltage analog control lines in mixed-signal instrumentation.

IC Role / Device Role / Timing Role: Active level shifter using emitter-follower or common-emitter topology to invert and scale voltage levels.

Use Value: V_CEO = −30 V and V_BE(on) = −600 to −750 mV enable reliable operation with ±12 V rails and predictable turn-on behavior.

Discrete Oscillator Core

LED Driver Switch

Use Scenario: Building low-frequency relaxation oscillators in timing circuits for blinkers or pulse generators.

IC Role / Device Role / Timing Role: Active gain element in RC-timed feedback loop, leveraging h_FE stability and low C_ob for predictable frequency drift.

Use Value: 6 pF Cob minimizes parasitic phase shift, while 150 MHz f_T ensures sufficient gain margin well above target oscillation frequencies (<1 MHz).

Use Scenario: Driving indicator LEDs in automotive dashboard modules requiring robust on/off control under varying supply conditions.

IC Role / Device Role / Timing Role: Saturated switch controlling LED anode connection to regulated supply via collector-emitter path.

Use Value: V_CE(sat) = −250 to −650 mV at I_C = −100 mA ensures minimal power loss and heat generation during continuous conduction.

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP small-signal transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
BC559BTA	Same TO-92-3 package and electrical specs, but h_FE Class B (200–450) - lower gain, tighter tolerance spread	Suitable for applications needing moderate gain consistency over temperature, e.g., fixed-gain buffer stages	Select BC559BTA when gain predictability matters more than maximum amplification; avoid where high h_FE is required for low-base-current drive
BC558BTA	V_CEO = −30 V same, but h_FE Class B (200–450) and higher noise figure (2–10 dB); no Class C variant available	Preferred in cost-sensitive general-purpose switching where noise is non-critical, e.g., relay drivers	Choose BC558BTA only if noise performance is secondary and gain >420 is not required; verify Cob and f_T meet circuit bandwidth needs

Compared with BC559BTA and BC558BTA, the BC559CBU delivers highest h_FE and lowest noise figure in the BC55x family, making it optimal for precision audio amplification and low-current gain-critical designs - though its Class C gain spread requires tighter biasing control.

Availability

BC559CBU is available at Aetrix Electronics and suitable for audio preamplifiers, discrete oscillator circuits, LED driver switches, and signal level-shifting applications requiring stable component supply and consistent low-noise performance.

Supply support for BC559CBU 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 delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.

The BC559CBU belongs to onsemi's legacy BC5xx PNP/NPN complementary transistor family, engineered for high-reliability analog signal conditioning and discrete logic interfacing in cost-sensitive, space-constrained designs.

FAQ

What is the h_FE range for BC559CBU?

The BC559CBU has a DC current gain (h_FE) range of 420 to 800 at V_CE = −5 V and I_C = −2 mA, classified as Class C per onsemi's datasheet. This high gain enables low-base-drive operation in amplifier and switching circuits. Designers must account for this wide spread when setting bias points - the BC559CBU requires careful resistor selection to maintain stability across the full h_FE range.

Is BC559CBU RoHS-compliant and lead-free?

Yes, the BC559CBU is Pb-free, halogen-free/BFR-free, and fully RoHS-compliant per EU Directive 2011/65/EU. It uses lead-free plating on its TO-92-3 (Case 135AR) package terminals and meets onsemi's environmental specifications. This makes the BC559CBU suitable for consumer electronics, industrial controls, and medical devices requiring strict material compliance.

What is the maximum collector-emitter voltage rating for BC559CBU?

The BC559CBU has a maximum collector-emitter voltage (V_CEO) rating of −30 V. This defines the absolute upper limit for reverse-biased collector-to-emitter voltage in active or cutoff operation. Exceeding −30 V risks avalanche breakdown; designers should maintain ≥20% derating margin in practical circuits - especially in inductive load switching or AC-coupled amplifier stages.

How does BC559CBU compare to BC549C in complementary use?

The BC559CBU is the designated PNP complement to the NPN BC549C, sharing matching h_FE Class C (420–800), noise performance, and TO-92-3 packaging. Their symmetrical characteristics allow balanced push-pull output stages and differential pairs with minimized offset and thermal drift. The BC559CBU's V_CEO = −30 V mirrors BC549C's V_CEO = +30 V, enabling true complementary rail-to-rail operation in discrete amplifier designs.

What is the typical noise figure of BC559CBU and at what conditions?

The BC559CBU has a noise figure of 1.2–4.0 dB measured at V_CE = −5 V, I_C = −200 µA, R_G = 2 kΩ, and frequency range 30–15,000 Hz. This low-noise specification is explicitly validated for the BC559 and BC560 variants - distinguishing them from BC556/557/558 - and confirms the BC559CBU's suitability for high-fidelity audio front-end amplification where signal-to-noise ratio is critical.

BC559CBU Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-226-3, TO-92-3 (TO-226AA)

Packaging:: Bulk

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:: 420 @ 2mA, 5V

Power - Max:: 500 mW

Frequency - Transition:: 150MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92-3

BC559CBU FAQ

1.How can I place an order for BC559CBU through Aetrix?

Please submit a Request for Quotation (RFQ) for BC559CBU 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 BC559CBU reliable?

The price and inventory of BC559CBU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC559CBU is usually 5 days.

3.What payment methods are accepted for BC559CBU?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC559CBU transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC559CBU?

BC559CBU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC559CBU 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 BC559CBU?

For technical support, including BC559CBU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC559CBU requirements.

6.How does Aetrix verify that BC559CBU is sourced from the original manufacturer or authorized distributors?

All BC559CBU 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 BC559CBU meets industry standards.

7.What is the process for return or replacement of BC559CBU?

All BC559CBU units undergo pre-shipment inspection (PSI). If there is an issue with BC559CBU, 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 BC559CBU part is unused and in its original packaging.

Return procedure for BC559CBU:

1.Submit a request within 90 days.

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

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