This reference design creates a 5V at 200mA from a 120VAC Input. This supply is to designed to fit into a very small volume with approximately 10mm total height. The UCC28720 primary side controller with a BJT power switch provides a low cost design. A TPS71433 is also used to provide an additional 3.3V rail. It is important to note the outputs are only functionally (not for safety) isolated from the input.