BC558 Bipolar Junction Transistors – BJT PNP 30V 100mA
The BC558 is a PNP epitaxial-silicon bipolar junction transistor designed for general-purpose switching and amplifier applications. It supports up to –30 V across the collector‑emitter junction and a continuous collector current of –100 mA, making it well suited for low‑to‑medium power audio and signal‑processing circuits.
Features
- PNP Epitaxial Silicon Construction
- Collector–Emitter Voltage (VCEO) = –30 V
- Collector Current (IC) = –100 mA
- Power Dissipation (PC) = 500 mW
- Low Saturation Voltages for Efficient Switching
- DC Current Gain (hFE) from 110 to 800
- Bandwidth (fT) = 150 MHz
- Complement to BC546–BC550 (NPN Series)
Specifications
| Parameter | Symbol | Value | Unit | Notes |
|---|---|---|---|---|
| Collector–Emitter Voltage | VCEO | –30 | V | Absolute Max |
| Collector–Base Voltage | VCBO | –30 | V | Absolute Max |
| Emitter–Base Voltage | VEBO | –5 | V | Absolute Max |
| Collector Current (DC) | IC | –100 | mA | |
| Collector Power Dissipation | PC | 500 | mW | TA = 25 °C |
| Junction Temperature | TJ | 150 | °C | Max Operating Temp |
| Storage Temperature | TSTG | –65 to +150 | °C | |
| DC Current Gain | hFE | 110 to 800 | — | VCE=–5 V, IC=–2 mA |
| Collector–Emitter Saturation Voltage | VCE(sat) | –90 to –300 | mV | IC=–10 mA |
| Base–Emitter On Voltage | VBE(on) | –600 to –750 | mV | IC=–2 mA |
| Transition Frequency | fT | 150 | MHz | VCE=–5 V, IC=–10 mA |
| Output Capacitance | Cob | 6 | pF | VCB=–10 V |
| Noise Figure | NF | 2 to 10 | dB | VCE=–5 V, IC=–200 µA |
BC558 as switch
BC558 as Amplifier
Applications
- Audio Frequency Preamplifiers: Ideal for low-noise input stages in microphones and audio devices.
- General-Purpose Switching: Suitable for driving relays, small motors, and other switching tasks.
- Signal Processing: Used in differential amplifier circuits and low-level analog signal manipulation.
- Complementary Amplifier Designs: Works well with NPN transistors like BC548 to create push-pull amplifier stages.
- Hobby Electronics Projects: Common in DIY circuits, educational kits, and basic analog electronics.