What the 40 V / 3 A rating means for your rail
The STPS640CB-TR is a dual Schottky rectifier in a common-cathode pair — two 3 A diodes sharing a cathode tab, so it handles up to 6 A total if the load splits evenly across both anodes, but each diode is rated 3 A average rectified individually. Forward voltage is 630 mV max at 3 A — that is the conduction loss floor.
Board-fit and package reality
The tape-and-reel packaging means it ships on a 13-inch reel for automated pick-and-place; the cut-tape option is for prototype or low-volume builds where a full reel is wasteful.
Switching speed and reverse leakage trade-off
The Schottky technology gives fast recovery — under 500 ns — which is typical for a 40 V Schottky; the speed is not the limiting factor in a 100 kHz or lower switching supply, but the reverse leakage of 100 µA at 40 V doubles or triples at elevated junction temperature and must be budgeted in the thermal calculation.
Lifecycle and compliance status
The base product number is STPS640, meaning the -TR suffix is the tape-and-reel packaging variant; the same die in a different reel or tube format carries the same electrical ratings.