onsemi BC558_J35Z

Overview

BC558_J35Z from onsemi is a PNP epitaxial silicon transistor designed for general-purpose switching and linear amplification in low-power analog and digital circuits. It features V_CEO = −30 V, I_C = −100 mA, h_FE = 200–450 (Class B), V_CE(sat) ≤ −300 mV at I_C = −10 mA/I_B = −0.5 mA, and f_T = 150 MHz - enabling use in audio preamplifiers, level shifters, and discrete logic interfaces.

For engineers reviewing the BC558_J35Z datasheet, pinout, applications, or equivalent options, key selection criteria include its −30 V V_CEO, TO-92-3 package compatibility, Class B h_FE range, low-noise capability (NF = 2–10 dB at 1 kHz), and complementarity to BC548/BC549 NPN transistors in push-pull stages.

Technical Context

The BC558_J35Z operates as a medium-gain, medium-voltage PNP bipolar junction transistor optimized for DC-coupled amplification and saturated switching. Its h_FE classification (B) ensures predictable current gain between 200 and 450 at I_C = −2 mA/V_CE = −5 V, while V_CE(sat) remains ≤ −300 mV under light drive conditions.

Thermal performance is defined by R_JA = 250 °C/W (FR-4 PCB, 76 mm × 114 mm), with PD = 500 mW derated at 4.0 mW/°C above 25°C. Its Cob = 6 pF at V_CB = −10 V supports stable operation up to mid-VHF frequencies without unintended resonance.

Key Specifications

Pinout & Package

BC558_J35Z is housed in a TO-92-3 plastic package (Case 135AR), lead-formed, with standard through-hole mounting. Dimensions: 4.83 mm × 4.76 mm × 3.6 mm.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BC558_J35Z, BC558BTA offers guaranteed onsemi traceability and standardized packaging, while BC557BTA delivers +15 V V_CEO headroom - both retain identical pinout, gain, and thermal behavior, making them drop-in viable alternatives in most non-margin-critical designs.

Availability

BC558_J35Z is available at Aetrix Electronics and suitable for audio preamplifiers, discrete logic level shifters, and LED driver circuits requiring stable component supply, long-lifecycle support, and RoHS-compliant sourcing.

Supply support for BC558_J35Z 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 management, analog, sensing, and connectivity solutions for automotive, industrial, and cloud infrastructure markets.

The BC558_J35Z belongs to onsemi's legacy BC5xx PNP/NPN transistor family - engineered for reliability, consistency, and broad compatibility in cost-sensitive, high-volume analog and mixed-signal applications.

FAQ

What is the maximum collector-emitter voltage rating for BC558_J35Z?

The BC558_J35Z has a maximum collector-emitter voltage (V_CEO) rating of −30 V, as specified in the Absolute Maximum Ratings table of the onsemi datasheet. This value defines the highest reverse-biased voltage the transistor can withstand between collector and emitter with the base open. Exceeding −30 V risks avalanche breakdown and permanent damage. The BC558_J35Z must not be used in circuits where transient or steady-state V_CE exceeds this limit without protective clamping.

Is BC558_J35Z pin-compatible with BC548 or BC549 NPN transistors?

BC558_J35Z is not pin-compatible with BC548 or BC549 - it is a PNP device with Collector/Base/Emitter pinout (1/2/3), whereas BC548/BC549 are NPN transistors with the same physical TO-92-3 pinout but opposite polarity. While they share identical mechanical footprint and pin numbering, their complementary nature means BC558_J35Z serves as the PNP counterpart in push-pull or differential pairs, not a direct replacement. Circuit topology must be adjusted accordingly when substituting BC558_J35Z for an NPN part.

What h_FE classification does BC558_J35Z belong to, and how is it verified?

BC558_J35Z is classified as Class B, with a guaranteed DC current gain (h_FE) range of 200–450 measured at V_CE = −5 V and I_C = −2 mA. This classification is confirmed in the "h_FE CLASSIFICATION" table on page 2 of the onsemi datasheet and applies to all BC558 variants including BC558_J35Z. The gain binning is performed during final test and marked on the device body per ordering codes (e.g., "BC558B").

Does BC558_J35Z meet RoHS and halogen-free requirements?

Yes, BC558_J35Z meets RoHS Directive 2011/65/EU and is both halogen-free and BFR-free, as explicitly stated in the "Features" section of the onsemi datasheet. This compliance is inherent to the TO-92-3 package construction and material set used for BC558_J35Z and all listed BC556–BC560 variants, ensuring environmental safety for industrial and consumer end products.

What is the thermal resistance (R_JA) of BC558_J35Z, and how does it affect power dissipation?

The BC558_J35Z has a junction-to-ambient thermal resistance (R_JA) of 250 °C/W under standard FR-4 PCB conditions (76 mm × 114 mm, minimum land pattern). At 25°C ambient, its maximum power dissipation is 500 mW, derating linearly by 4.0 mW/°C above that temperature. Thus, at 75°C ambient, usable power drops to 300 mW - a critical constraint for thermally dense layouts or sealed enclosures where BC558_J35Z may operate near its 150°C junction limit.