Integrated 1.5A Synchronous Regulators from STMicroelectronics Simplify High-Efficiency Power Conversion

STMicroelectronics L6981CDR L6981NDR

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.

STMicroelectronics - L6981CDR, L6981NDR

Rated to deliver up to 1.5 A, with 90% typical efficiency at full load, the L6981 converters are available in two variants optimized for light-load efficiency and noise performance.

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

Both variants can accept an input voltage from 3.5 V to 38 V, making them well suited to use in 24 V industrial bus-powered applications, 12 V and 24 V battery-powered equipment, HVAC power supplies, decentralized 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, over-voltage protection, and thermal protection. There is also soft-start circuitry that limits inrush current and ensures a constant output-voltage slope. An Enable pin is provided, which permits power-up/power-down sequencing and allows a synchronizing clock signal to be applied to the L6981N low-noise converters. The L6981 is included in ST’s 10-year longevity program that ensures long-term component supply.

The STEVAL-L6981CDR evaluation board for the low-current converter and STEVAL-L6981NDR for the low-noise version are available to help designers accelerate device selection in power-supply development.

The STEVAL-L6981CDR Evaluation Board
The STEVAL-L6981CDR Evaluation Board.

The L6981 is in production now, in the proven, rugged SO8L package, from $1.00 for orders over 1000 pieces.

1-4 Layer PCBs $2

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