Many Linear Technology devices use an external PNP transistor to sense temperature. Common examples are LTC3880, LTC3883 and LTC2974. Accurate temperature sensing depends on proper PNP selection, ...

In the early days, PNP bipolar transistors were common, but the bulk of circuits you see today use NPN transistors. As [Aaron Danner] points out, many people think PNP transistors are “backward” but ...

For circuit designs that use complementarybipolar transistors,you sometimes need to sort the NPNand PNP transistors to have matchingdc-current gains (β). One example of acircuit requiring matching is ...