High current gain bipolar transistors from ST as good as FETs
For electronics engineering students, the most asked question in the tests and the job interview is the advantages and disadvantages of MOSFETs over bipolar junction transistor. The key advantage of field effect transistor over bipolar junction transistor as we all know is less power consumption. But after reading the news below, it may not be so.
ST Microelectronics has improved the power efficiency of bipolar junction transistor to be as good as MOSFET. ST Microelectronics has announced a bipolar junction PNP transistor coded 3STL2540 with rating of -40V/-5A capable of full saturation with maximum voltage drop of 200mV at only 10mA base current. It can achieve an equivalent on-resistance of on 90 milli ohms, which is close to the performance of comparable super logic-level MOSFETs.
ST has fabricated these transistors by using double-metal planar base island technology. 3STL2540 offer high current gain (hFE) of at least 100 over a wide output-voltage range from 0.2 to 10 V and a temperature range from -30°C to 150°C, offering the industry’s lowest conduction losses for this type of device, claims ST. The package is also thermally efficient, package called PowerFLAT measures 0.6mm high with a 2mm x 2mm footprint.
The 3STL2540 is in volume production, and available from $0.30 in the PowerFLAT 2x2 package for orders over 1,000 pieces.
To update you more on the bipolar junction transistors, there is also a trend of building silicon carbide-based bipolar junction transistors for use in power conversion systems.
Power IC expert iWatt, which is now acquired by Dialog Semiconductor plc has launched the industry’s first digital pulse width modulation (PWM) controller that can easily and efficiently drive low-cost, 10W power bipolar junction transistor (BJT) switches to reduce the BOM cost in 5V/2A smartphone adapters and chargers.