STMicroelectronics L6981 synchronous step-down regulators

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STMicroelectronics has introduced L6981 synchronous step-down regulators, extending the family of high-efficiency converters that simplify power-supply design by integrating power elements, feedback circuitry and safety features on-chip. Rated to deliver up to 1.5 A, with 90% typical efficiency at full load, the converters are available in two variants optimised for light-load efficiency and noise performance.

The L6981C for low-current operation uses pulse skipping to maximise efficiency at light loads extending the runtime of battery-powered devices. The L6981N prioritises low noise by operating permanently in PWM (pulse-width modulation) mode at constant switching frequency and minimising voltage ripple at light loads.

Both variants can accept an input voltage from 3.5 to 38 V, making them suited to use in 24 V industrial bus-powered applications, 12 and 24 V battery-powered equipment, HVAC power supplies, decentralised intelligent nodes, smart sensors and always-on applications. The output voltage can be adjusted from 0.85 V up to the input-voltage value using external resistors.

Integrated features include high-side and low-side NMOS power transistors, feedback-loop compensation, overvoltage protection and thermal protection. There is also soft-start circuitry that limits inrush current and should ensure a constant output-voltage slope. An Enable pin is provided, which permits power-up/power-down sequencing and allows a synchronising clock signal to be applied to the L6981N low-noise converters.

For more information: www.st.com/buckregulators.