Normaly, it must be the same, but if you need something very special, like some transistor parameters, there are small differences between one manufacturer and other. The are not the same even if it have the same code like 2N2222. A particular case is the 4N25 optocoupler, if you compare the datasheets from differents manufacturers you will be surprised.....
hi
there is alot of parameters that depend on ur
application
like the must frequency it can work on
and the must current
so u must post ur application to get
the perfect parameters
and ofcourse the mechanical data and pin configuration for ur pcb design, well if u get an unknown transistor how do u kno what is the application for tat, i mean other hat general purpose trans most of them are optimized for various appications like rf, audio, etc and in comarision sheet u also can get alternatives.
more over wen a transistor is not available (often happens to me ) u can compare the data with the transistors u have , and it is pretty much possible that u will get a common of them