The MAX17690 is a peak current mode, fixed-frequency switching controller specifically designed for the isolated flyback topology operating in Discontinuous Conduction Mode (DCM). The device senses the isolated output voltage directly from the primary-side flyback waveform during the off-time of the primary switch. No auxiliary winding or optocoupler is required for output voltage regulation. The MAX17690 is designed to operate over a wide supply range from 4.5V to 60V. The switching frequency is programmable from 50kHz to 250kHz. A EN/UVLO pin allows the user to turn on/off the power supply precisely at the desired input voltage. The MAX17690 provides an input overvoltage protection through the OVI pin. The 7V internal LDO output of the MAX17690 makes it suitable for switching both logic-level and standard MOSFETs used in flyback converters. With 2A/4A source/sink currents, the MAX17690 is ideal for driving low RDS(ON) power MOSFETs with fast gate transition times. The MAX17690 provides an adjustable soft-start feature to limit the inrush current during startup. The MAX17690 provides temperature compensation for the output diode forward voltage drop. The MAX17690 has robust hiccup-protection and thermal protection schemes, and is available in a space-saving 16-pin 3mm x 3mm TQFN package with a temperature range from -40°C to 125°C.