onsemi BC559BTAR

Overview

BC559BTAR from onsemi is a PNP epitaxial silicon transistor designed for low-noise amplification and general-purpose switching in analog and digital circuits. It features V_CEO = −30 V, I_C = −100 mA, h_FE = 200–450 (Class B), f_T = 150 MHz, and V_BE(on) ≈ −660 mV at I_C = −2 mA - enabling use in audio preamplifiers, signal conditioning stages, and discrete logic interfaces.

For engineers reviewing the BC559BTAR datasheet, pinout, applications, or equivalent options, key selection criteria include its low-noise performance (NF = 1.2–4.0 dB at 30–15 kHz), TO-92-3 package compatibility, complementary pairing with BC549/BC550 NPN devices, and RoHS-compliant Pb-free construction.

Technical Context

The BC559BTAR operates as a medium-speed, low-noise PNP bipolar junction transistor optimized for linear amplification and saturated switching. Its h_FE classification (B) ensures predictable DC gain between 200 and 450 at V_CE = −5 V and I_C = −2 mA, while f_T = 150 MHz supports audio-frequency and low-MHz signal handling.

Thermal design is constrained by R_JA = 250 °C/W and P_D = 500 mW (derated above 25°C), requiring minimal heatsinking in PCB-mounted applications. The device's Cob = 6 pF at V_CB = −10 V enables stable high-frequency operation without excessive Miller effect in common-emitter configurations.

Key Specifications

Pinout & Package

BC559BTAR is housed in a TO-92-3 plastic package (Case 135AR), lead-formed for through-hole mounting. Dimensions are 4.83 mm × 4.76 mm with standard 2.54 mm pin pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BC559CTA and BC558BTA, BC559BTAR offers the optimal balance of gain linearity (200–450), low-noise operation (1.2–4.0 dB), and 150 MHz bandwidth - making it the preferred choice for audio front-ends and precision analog interfaces where parameter predictability matters.

Availability

BC559BTAR is available at Aetrix Electronics and suitable for audio preamplifiers, sensor signal conditioning circuits, and industrial control switching applications requiring stable component supply, long-term manufacturability, and RoHS-compliant sourcing.

Supply support for BC559BTAR 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 management, analog, and sensing solutions for automotive, industrial, and consumer markets.

The BC559BTAR belongs to onsemi's legacy BC5xx PNP/NPN transistor family, engineered for reliability and consistency in analog signal paths, discrete logic, and cost-sensitive linear applications.

FAQ

What is the maximum collector-emitter voltage rating for BC559BTAR?

The BC559BTAR has a maximum collector-emitter voltage (V_CEO) rating of −30 V at T_A = 25°C. This rating applies under DC conditions and defines the upper limit for safe operation in negative-rail circuits. Exceeding this voltage risks avalanche breakdown and permanent device damage. Derating is not specified beyond ambient temperature effects on power dissipation.

Is BC559BTAR suitable for low-noise audio amplification?

Yes, BC559BTAR is explicitly characterized for low-noise operation with a noise figure (NF) of 1.2–4.0 dB measured at 30–15,000 Hz, V_CE = −5 V, I_C = −200 µA, and R_G = 2 kΩ. This makes BC559BTAR appropriate for microphone preamplifiers, sensor front-ends, and other analog stages where signal-to-noise ratio is critical.

What package type does BC559BTAR use, and is it lead-formed?

BC559BTAR uses the TO-92-3 plastic package (Case 135AR), which is lead-formed for through-hole mounting. Its mechanical outline matches the 4.83 mm × 4.76 mm footprint with standard 2.54 mm pin spacing. This differs from the straight-lead Case 135AN variant used in some BC556 variants.

How does BC559BTAR compare to BC559CTA in terms of DC current gain?

BC559BTAR is classified as Class B with h_FE = 200–450 at V_CE = −5 V and I_C = −2 mA, whereas BC559CTA is Class C with h_FE = 420–800 under identical test conditions. Both share identical absolute maximum ratings and thermal characteristics, but BC559BTAR provides tighter gain distribution for matched-pair or feedback-stable designs.

Does BC559BTAR have RoHS and halogen-free compliance?

Yes, BC559BTAR is Pb-free, halogen-free/BFR-free, and fully RoHS compliant per EU Directive 2011/65/EU. This compliance is confirmed in the official onsemi datasheet (Rev. 3, June 2024) and applies to all units shipped in TO-92-3 Case 135AR packaging.