The STTH20LCD06CT is a 600 V, 10 A fast-recovery epitaxial diode from STMicroelectronics, configured as a common-cathode pair in a TO-220-3 package. Its 50 ns reverse recovery time (trr) targets continuous-current-mode (CCM) boost PFC stages and hard-switching converters where stored charge recovery directly sets the switching loss and EMI signature. The 1 µA reverse leakage at 600 V rated reverse voltage is typical for a fast epitaxial structure at 25°C; expect it to rise with junction temperature, but the 175°C maximum junction rating gives headroom for thermal derating.
STMicroelectronics lists the STTH20LCD06CT as Obsolete.
Through-hole TO-220 — thermal and mechanical fit
The TO-220-3 package is a through-hole tab-mount with a metal backplate for heatsink attachment. The common-cathode configuration means the tab is electrically live at the cathode potential — insulate the heatsink or use a thermal pad. Lead pitch is the standard 2.54 mm (0.1 in) for TO-220, so it drops into existing PCB layouts without footprint changes.