Description

Maxim's Rainier family of isolated power devices enablecooler, smaller, and simpler power-supply solutions. TheMAX17691A/B is a high efficiency No-Opto integratednMOSFET flyback converter that uses fixed frequencypeak current mode control. The device senses the isolatedoutput voltage directly from the primary-side flyback waveformduring secondary-side rectifier conduction. No secondary-side error amplifier and optocoupler are requiredto provide an accurate, isolated, regulated output voltage,saving up to 20% of PCB space normally required for atraditional flyback converter.The MAX17691A/B features a low RDSON, 76V, 170mΩintegrated nMOSFET primary switch and is designed tooperate over a wide supply range from 4.2V to 60V. Theswitching frequency of the device is programmable from100kHz to 350kHz. An EN/UVLO feature allows the userto turn ON/OFF the power converter precisely at the desiredinput voltage. Input overvoltage protection can beimplemented using the OVI pin (MAX17691A only). Softstartlimits inrush current at startup. The MAX17691A/Bsupports external clock synchronization to avoid low-frequency“beats” on the input bus in systems with multipleconverters. The device also has programmable frequencydithering for low-EMI, spread-spectrum operation.The MAX17691A/B allows temperature compensation forvariations in the output rectifier diode forward voltagedrop. The MAX17691A is internally compensated for loopstability, while the MAX17691B offers external loop compensationflexibility. The MAX17691A/B has robust hiccup-protection and thermal protection schemes, and isavailable in a space-saving 12-pin, 3mm x 3mm TDFNpackage with a temperature range from -40°C to +125°C.ApplicationsIsolated Power SuppliesPLC I/O ModulesIGBT Gate Drive SuppliesIndustrial and Telecom Applications