Vishay sells a whole lot of most everything across its numerous divisions. Its General Semiconductor division is responsible for their SMF48A-M3-08 TVS diode, amongst other products. We’ve received a few questions concerning part markings on these devices, namely what the difference between ‘CX’ and ‘PX’ is and which of these markings is correct.
For this product, the ‘PX’ is correct. ‘CX’ is a standard version of this product, while ‘PX’ is the halogen-free version. The ‘M’ in this diode’s part number indicates halogen-free status, so these products would be marked ‘PX’.