The BD139 is a mediumpower NPN bipolar junction transistor (BJT) housed in a TO126 (SOT32) plastic package. It is designed for audio amplifiers and drivers utilizing complementary or quasicomplementary circuits and is the NPN complement to the PNP transistor BD140.
| Parameter | Value | Notes |
|---|---|---|
| -- | -- | -- |
| Collector-Emitter Voltage (VCEO) | 80V | Maximum continuous voltage |
| Collector-Base Voltage (VCBO) | 80V | |
| Emitter-Base Voltage (VEBO) | 5V | |
| Collector Current (IC) | 1.5A | Continuous current rating |
| Power Dissipation (Ptot) | 1.25W (without heatsink) / 12.5W (with heatsink) | With proper heatsinking |
| DC Current Gain (hFE) | 40 - 250 | Depends on variant and conditions |
| Transition Frequency (fT) | 190 MHz | Typical value |
| Operating Junction Temperature | -55°C to +150°C |
Complementary NPN Design - Designed as a complementary transistor to the BD140 (PNP)
High Current Capability 1.5A continuous collector current for mediumpower applications
Low Saturation Voltage - 0.5V max at IC = 500mA ensures low conduction losses
Versatile Performance - 190 MHz transition frequency for suitability in audio and driver stages
√ Ready to use A standard and welldocumented power transistor
√ Medium power capability - Suitable for a wide range of applications
√ Multiple hFE ranks - Available in 6, 10, and 16 classifications with different gain ranges
Avoid exceeding the maximum voltage ratings the collector-emitter voltage (VCEO) of 80V is critical
-Avoid exceeding the maximum junction temperature of 150°C
-Avoid using this transistor as a direct replacement without confirming the pinout and specifications