45 V, 500 mA PNP — the general-purpose switching workhorse
The Infineon BC80740B5003XT is a PNP epitaxial planar transistor in the BC807 series, housed in a PG-SOT23 surface-mount package. It is designed for general-purpose switching and linear amplification in circuits where the collector rail stays below 45 V and the load draws up to 500 mA continuous.
200 MHz transition frequency — gain bandwidth for switching and linear stages
Transition frequency is 200 MHz. Gain drops below unity above that frequency.
hFE min 250 at 100 mA — low base-drive requirement
The DC current gain is guaranteed at a minimum of 250 when the collector current is 100 mA and Vce is 1 V. This means the base current needed to saturate the transistor at 100 mA load is at most 0.4 mA, which a logic gate or a low-current GPIO pin can supply directly without an extra driver stage.
Saturation voltage and leakage — the fine print for low-voltage rails
Vce(sat) is 700 mV maximum at 50 mA base current and 500 mA collector current. Collector cutoff leakage is 100 nA maximum.