600 V, 12 A fast recovery diode in TO-220AC
The STTH12R06D is a 600 V, 12 A average rectified current fast recovery diode from STMicroelectronics, housed in a TO-220AC through-hole package. Its 45 ns reverse recovery time (trr) suits continuous-current-mode (CCM) boost PFC stages and high-frequency rectification where switching losses must be kept low. Forward voltage is 2.9 V maximum at 12 A — this sets the conduction loss floor in the thermal design. Reverse leakage is 45 µA at the 600 V rated blocking voltage, a figure that rises with junction temperature and should be factored into standby-power budgets. Maximum junction temperature is 175 °C, giving headroom for high-ambient or tightly-enclosed power supplies. The TO-220AC package with its exposed metal tab conducts heat to a heatsink or PCB copper plane — the tab is electrically common with the cathode.
Package variants and second-source fit
The closest functional peer is the STTH12R06FP, which uses the same STTH12 die (600 V, 12 A, 45 ns trr) but in a TO-220FP fully-insulated package. The STTH12R06D in TO-220AC has the exposed metal tab; the FP variant's full plastic body eliminates the need for an insulating pad and washer, at the cost of higher thermal resistance junction-to-case. The STTH12R06DIRG shares the same TO-220AC package and die but is supplied in tape-and-reel rather than tube. If a board was laid out for the STTH12R06FP, the STTH12R06D will not drop in without a mounting change — the TO-220AC tab requires electrical isolation from the heatsink, whereas the FP package does not. The electrical performance is otherwise identical.