The LinkSwitch-LP family is designed to replace inefficient line frequency linear transformer based power supplies with output powers < 2.5 W in applications such as cell/cordless phones, PDAs, digital cameras, and portable audio players. LinkSwitch-LP may also be used as auxiliary supplies employed in applications such as white goods. LinkSwitch-LP combines a high voltage power MOSFET switch with an ON/OFF controller in one device. It is completely self-powered from the DRAIN pin, has a jittered switching frequency for low EMI and is fully fault protected. Auto-restart limits device and circuit dissipation during overload and output short circuit conditions while hysteretic over-temperature protection disables the internal MOSFET during thermal faults. EcoSmart® technology enables designs to easily attain < 150 mW no-load consumption, meeting worldwide energy efficiency requirements. LinkSwitch-LP is designed to operate without the need for a primary-side clamp circuit for output powers below 2.5 W and thus, dramatically reduces component count and total system cost. Figure 1 shows a LinkSwitch-LP based 2 W power supply without a primary-side clamp. The LinkSwitch-LP family has been optimized to give an approximate CV/CC output characteristic when feedback is provided from an auxillary or bias winding on the transformer. This is ideal for applications replacing a line frequency transformer, providing a compatible output characteristic but with reduced overload, short circuit current and variation with input line voltage.