Other Parts Discussed in Thread: UCC28740,
UCC28742 is recently released, as a spin of UCC28740 with same or similar performance, both are SSR flyback controllers. A previous reference design using UCC28740 can be easily converted to be with UCC28742 with only a few parameter value changes.
The three main differences between UCC28742 and UCC28740:
(1) Footprint: UCC28742 - SOT23-6, vs. UCC28740 - SOIC-7 (so UCC28742 footprint is much smaller)
(2) UCC28742 does not have HV pin (high voltage start). Its initial power-on start is by a startup resistor tied from the VDD pin to Vbulk.
(3) UCC28742 does not have constant current operation; when reach over current limit, the device will be in shutdown and auto-retry, i.e. in hiccup operation, after 120ms delay timer.
All other performances are similar, and all design steps are the same.
All existing reference designs using UCC28740 can be easily converted to UCC28742-based designs as long as the above three differences noticed ok.
The differentiated features to use UCC28742, compared to UCC28740, include smaller footprint (so possible cost saving), smaller footprint, and OCP in hiccup operation.
