The MAX17497A/MAX17497B devices from Maxim include both a current-mode fixed-frequency PWM 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 (85...265 V AC) applications, while the MAX17497B supports undervoltage lockout (UVLO) thresholds suitable to low-voltage DC-DC applications. Both devices also include a 3.3 V fixed-output synchronous step-down regulator that delivers up to 600 mA load current.

The switching frequency of the MAX17497A flyback converter is 250 kHz, while that of the MAX17497B flyback/boost converter is 500 kHz. The internally compensated synchronous step-down regulator switches at 1 MHz 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 shuts down when the DC input voltage exceeds the desired maximum value.

The devices are available in a space-saving 16-pin (3 mm × 3 mm) TQFN package with 0.5 mm lead spacing.