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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 noniso lated 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 suit able 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.

The switching frequency of the MAX17497A flyback converter is 250kHz, while the MAX17497B flyback/ boost converter is 500kHz. The internally compensated synchronous step-down regulator switches at 1MHz on both versions. These frequencies allow the use of tiny magnetic and filter components resulting in compact, cost-effective power supplies. An EN/UVLO input allows the user to start the power supply precisely at the desired input voltage, while also functioning as an on/off pin. The OVI pin enables implementation of an input overvoltage protection scheme that ensures the converter shutsdown when the DC input voltage exceeds the desired maximum value.

Benefits and Features

1. Reduced Component Count and Board Space
2. Minimal Radio Interference
3. Reduced Inrush Current
4. Reduced Power Dissipation Under Fault
5. Robust Protection Features
6. Optimized Loop Performance