Maxim's Rainier family of isolated power devices enable cooler, smaller, and simpler power-supply solutions. The MAX17691A/B is a high efficiency No-Opto integrated nMOSFET flyback converter that uses fixed frequency peak current mode control. The device senses the isolated output voltage directly from the primary-side flyback waveform during secondary-side rectifier conduction. No secondary-side error amplifier and optocoupler are required to provide an accurate, isolated, regulated output voltage, saving up to 20% of PCB space normally required for a traditional flyback converter.

The MAX17691A/B features a low R_DSON, 76V, 170mΩ integrated nMOSFET primary switch and is designed to operate over a wide supply range from 4.2V to 60V. The switching frequency of the device is programmable from 100kHz to 350kHz. An EN/UVLO feature allows the user to turn ON/OFF the power converter precisely at the desired input volt­age. Input overvoltage protection can be implemented using the OVI pin (MAX17691A only). Soft-start limits inrush current at startup. The MAX17691A/B supports external clock synchronization to avoid low-frequency “beats” on the input bus in systems with multiple converters. The device also has programmable frequency dithering for low-EMI, spread-spectrum operation.

The MAX17691A/B allows temperature compensation for variations in the output rectifier diode forward voltage drop. The MAX17691A is internally compensated for loop stability, while the MAX17691B offers external loop compensation flexibility. The MAX17691A/B has robust hiccup-protection and thermal protection schemes, and is available in a space-saving 12-pin, 3mm x 3mm TDFN package with a temperature range from -40°C to +125°C.