General Description
The MAX17497A/MAX17497B include both a current mode fixed-frequency flyback converter and a synchronous step-down regulator. They contain all the control circuitry required to design wide input-voltage nonisolated power supplies to supply multiple output rails for smart meters, industrial control, and other similar applications. The MAX17497A has its rising/falling undervoltage lockout (UVLO) thresholds optimized for universal offline (85V AC to 265V AC) applications, while the MAX17497B supports undervoltage lockout (UVLO) thresholds suitable to low-voltage DC-DC applications. Both devices also include a 3.3V fixed-output synchronous step-down regulator that delivers up to 600mA load current.

Benefits and Features
♦ Reduced Component Count and Board Space
   ◇ Flyback/Boost with Integrated Internally
      Compensated Step-Down Regulator
   ◇ No Current-Sense Resistor
   ◇ Space-Saving 16-Pin (3mm x 3mm) TQFN
      Package
♦ Minimal Radio Interference
   ◇ 250kHz Switching in Offline Version
      Minimizes Interference with Radio Receivers
      in Smart Meter Applications
♦ Reduced Inrush Current
   ◇ Programmable Flyback/Boost Soft-Start
   ◇ Internal Digital Soft-Start for Step-Down
      Regulator
♦ Reduced Power Dissipation Under Fault
   ◇ Hiccup Mode Overcurrent Protection
   ◇ Thermal Shutdown with Hysteresis
♦ Robust Protection Features
   ◇ Flyback/Boost Programmable Current Limit
   ◇ Input Overvoltage Protection
♦ Optimized Loop Performance
   ◇ Programmable Slope Compensation for
      Flyback/Boost Maximizes Obtainable Phase
      Margin
♦ High Efficiency
   ◇ Low RDSON, 150mI, 65V-Rated Internal
      nMOSFET
   ◇ 3.3V Step-Down Regulator Efficiency Greater
      Than 90%
♦ Optional Spread Spectrum

Applications
   AC-DC Power Supplies for Smart Meter Applications
   Universal-Input Offline AC-DC Power Supplies
   Wide-Range DC Input Flyback/Boost Industrial Power Supplies