My Inquiry
My Account
onsemi BC559BU
,TO-226_straightlead.jpg)
- Part No.:
- BC559BU
- Manufacturer:
- onsemi
- Category:
- Single Bipolar Transistors
- Package:
- TO-226-3, TO-92-3 (TO-226AA)
- Datasheet:
-
BC559BU.pdf
- Description:
- TRANS PNP 30V 0.1A TO-92-3
- Quantity:
- Payment:
- Shipping:
Inventory:2,584
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
BC559BU from onsemi is a PNP epitaxial silicon transistor optimized for low-noise amplification and general-purpose switching, with VCEO = −30 V, IC = −100 mA, hFE = 420–800 (Class C), fT = 150 MHz, and VBE(on) = −600 to −750 mV at IC = −2 mA - used in audio preamplifier stages, sensor signal conditioning, and discrete logic interface circuits.
For engineers reviewing the BC559BU datasheet, pinout, applications, or equivalent options, key selection criteria include low-noise figure (1.2–4.0 dB at 30–15 kHz), TO-92-3 package compatibility, complementary pairing with BC549/BC550, and verified performance under −5 V VCE, −2 mA IC bias conditions.
Technical Context
The BC559BU operates as a medium-gain, low-noise PNP bipolar junction transistor with fixed emitter-base and collector-base junction geometry optimized for linear amplification below 150 MHz. Its hFE classification (C-grade) ensures minimum DC current gain of 420 at −5 V VCE and −2 mA IC, while noise figure is specified across 30–15,000 Hz with RG = 2 kΩ source impedance.
Thermal design relies on RJA = 250 °C/W (FR-4 PCB, 76 mm × 114 mm), PD = 500 mW at 25°C derating at 4.0 mW/°C above ambient. Absolute maximum ratings confirm safe operation up to TJ = 150°C, VCBO = −30 V, and pulsed ICP = −200 mA.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | −30 V - supports rail-to-rail operation in negative-supply analog stages up to −30 V collector swing. |
| IC (DC) | −100 mA - enables drive capability for small-signal loads including LED indicators and relay coils. |
| hFE (Class C) | 420–800 - provides stable current amplification for high-fidelity audio gain blocks without external feedback compensation. |
| fT | 150 MHz - allows use in RF front-end buffers and wideband instrumentation amplifier input stages. |
| Noise Figure | 1.2–4.0 dB (30–15 kHz, RG = 2 kΩ) - meets low-noise requirements for microphone preamps and precision sensor interfaces. |
| VBE(on) | −600 to −750 mV @ IC = −2 mA - defines predictable base drive voltage for accurate bias network design. |
| PD | 500 mW @ 25°C - sets thermal limit for continuous operation on standard FR-4 PCBs without heatsinking. |
Pinout & Package
BC559BU is housed in a TO-92-3 plastic package (Case 135AR), lead-formed configuration, with standardized pin assignment: Pin 1 = Collector, Pin 2 = Base, Pin 3 = Emitter.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Collector) | Current sink node | Connected to negative supply rail or load return path; handles full output current up to −100 mA DC. |
| 2 (Base) | Control input | Receives forward-biased current to enable conduction; requires −600 to −750 mV relative to emitter for turn-on. |
| 3 (Emitter) | Reference terminal | Typically tied to circuit ground or positive rail in PNP common-emitter configurations; establishes bias reference point. |
Key Features
| Feature | Design Value |
|---|---|
| Low-noise amplification | 1.2 dB min NF at audio band (30–15 kHz), enabling clean signal gain in microphone and sensor front-ends. |
| High DC current gain (hFE) | 420–800 range (Class C) ensures consistent amplification across production lots without gain-bin sorting. |
| Complementary pairing | Designed as PNP counterpart to BC549/BC550 NPN transistors, supporting matched differential pair and push-pull stage implementation. |
| Pb-free, RoHS-compliant | Meets EU RoHS Directive 2011/65/EU and halogen-free/BFR-free requirements for industrial and consumer end-equipment. |
Applications
| Audio Preamp Stage | Sensor Signal Conditioning |
|---|---|
|
Use Scenario: Amplifying weak signals from electret microphones or piezoelectric sensors before ADC sampling. IC Role / Device Role / Timing Role: Low-noise PNP gain stage in common-emitter configuration with emitter degeneration. Use Value: Achieves 1.2 dB noise figure at 1 kHz, preserving SNR in battery-powered voice recorders and IoT acoustic monitors. |
Use Scenario: Converting low-level analog outputs from temperature or pressure transducers into robust voltage levels. IC Role / Device Role / Timing Role: Linear amplifier in transimpedance or differential gain topology with stable hFE over temperature. Use Value: Delivers 420–800 hFE and −30 V VCEO headroom for accurate 0–5 V scaling in industrial sensor modules. |
| Discrete Logic Interface | Negative-Supply Switching |
|
Use Scenario: Level-shifting TTL/CMOS outputs to drive legacy −5 V or −12 V logic families or optocoupler inputs. IC Role / Device Role / Timing Role: Saturated switch in common-emitter mode with fast VCE(sat) ≤ −300 mV at IC = −10 mA. Use Value: Enables reliable interfacing between modern MCU GPIOs and legacy industrial control systems using negative rails. |
Use Scenario: Controlling power delivery to analog subsystems (e.g., op-amp rails, DAC references) in dual-supply designs. IC Role / Device Role / Timing Role: High-side PNP switch regulating −30 V supply paths with minimal dropout voltage. Use Value: Supports precise rail enable/disable with VCE(sat) ≤ −650 mV at −100 mA, minimizing power loss in programmable power supplies. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PNP transistor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BC559BTA | Same die, identical electrical specs, but packaged in TO-92-3 Case 135AR with fan-fold shipping (2,000 units). | Identical functional behavior; differs only in packaging format and reel/fan-fold orientation. | Select BC559BTA for automated pick-and-place assembly requiring tape-and-reel or fan-fold delivery. |
| BC559CTA | Higher hFE bin (420–800 vs. 200–450 for B-grade); otherwise identical VCEO, fT, and noise performance. | Better suited for ultra-low-distortion amplifiers where gain consistency reduces need for trimming. | Choose BC559CTA when tighter hFE tolerance is required in high-precision analog gain blocks. |
Compared with BC559BTA and BC559CTA, the BC559BU offers identical core transistor characteristics but is distinguished by its bulk-packed, straight-lead TO-92-3 configuration - making it optimal for prototyping, manual soldering, and low-volume production where tape handling is unnecessary.
Availability
BC559BU is available at Aetrix Electronics and suitable for audio preamplifier stages, sensor signal conditioning circuits, and discrete logic interface designs requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.
Supply support for BC559BU 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 manufacturer specializing in energy-efficient power, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and IoT applications.
The BC559BU belongs to onsemi's legacy BC-series general-purpose bipolar transistor family, designed for cost-sensitive, high-reliability analog and switching functions in consumer, industrial, and communications equipment.
FAQ
What is the pin configuration of the BC559BU?
The BC559BU uses a TO-92-3 package (Case 135AR) with standardized pinout: Pin 1 is Collector, Pin 2 is Base, and Pin 3 is Emitter. This configuration is consistent across all BC55x series PNP transistors and matches JEDEC TO-92 mechanical standards. The BC559BU pinout enables direct replacement in existing PCB layouts designed for BC556–BC560 variants with same-case footprint.
Is the BC559BU suitable for low-noise audio applications?
Yes, the BC559BU is explicitly characterized for low-noise performance: its noise figure is 1.2–4.0 dB at frequencies from 30 Hz to 15 kHz with RG = 2 kΩ, meeting requirements for electret microphone preamplifiers and line-level buffer stages. The BC559BU achieves this via optimized epitaxial base structure and tight hFE binning (Class C), ensuring repeatable noise behavior across production lots.
What is the maximum operating temperature for the BC559BU?
The BC559BU has a maximum junction temperature (TJ) of 150°C and a storage temperature range of −65°C to +150°C. Its thermal resistance RJA is 250°C/W on a standard FR-4 PCB (76 mm × 114 mm), allowing continuous operation at full 500 mW dissipation only below 25°C ambient - above that, derating applies at 4.0 mW/°C. This makes the BC559BU suitable for enclosed industrial enclosures with moderate airflow.
How does the BC559BU compare to the BC549 NPN transistor?
The BC559BU is the designated PNP complement to the BC549 NPN transistor, sharing identical package (TO-92-3), voltage ratings (VCEO = −30 V / +30 V), current capability (±100 mA), and noise performance. Their matched hFE ranges and thermal characteristics allow balanced differential pair design, push-pull output stages, and complementary symmetry in analog signal paths - a key advantage of the BC559BU in dual-rail amplifier topologies.
Does the BC559BU meet RoHS and environmental compliance standards?
Yes, the BC559BU is Pb-free, halogen-free, and BFR-free, fully compliant with EU RoHS Directive 2011/65/EU. onsemi confirms this status in the official datasheet revision (June 2024, Rev. 3), and the device carries no exemptions. The BC559BU is qualified for use in consumer electronics, industrial controls, and medical devices where restricted substance compliance is mandatory.
BC559BU 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:
- 110 @ 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
BC559BU FAQ
1.How can I place an order for BC559BU through Aetrix?
Please submit a Request for Quotation (RFQ) for BC559BU 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 BC559BU reliable?
The price and inventory of BC559BU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC559BU is usually 5 days.
3.What payment methods are accepted for BC559BU?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC559BU transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BC559BU?
BC559BU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BC559BU 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 BC559BU?
For technical support, including BC559BU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC559BU requirements.
6.How does Aetrix verify that BC559BU is sourced from the original manufacturer or authorized distributors?
All BC559BU 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 BC559BU meets industry standards.
7.What is the process for return or replacement of BC559BU?
All BC559BU units undergo pre-shipment inspection (PSI). If there is an issue with BC559BU, 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 BC559BU part is unused and in its original packaging.
Return procedure for BC559BU:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BC559BU Tags
-
MMBT3906LT1G
onsemi
-
MMBT3904-7-F
Diodes Incorporated
-
MMBT3904LT1G
onsemi
-
MMBT3906-7-F
Diodes Incorporated
-
MMBT3904-TP
Micro Commercial Co
-
MMBT2222A-7-F
Diodes Incorporated
-
BC846BLT1G
onsemi
-
BC847B,215
Nexperia USA Inc.
-
SMMBT3904LT1G
onsemi
-
MMBT2222A-TP
Micro Commercial Co
-
MMBTA06LT1G
onsemi
-
MMBT2222ALT1G
onsemi
Tech Hub
Counterfeit components can hide behind convincing markings and passing basic function tests. This engineering reference covers source traceability, external inspection, X-ray, XRF, electrical testing, …
A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
