INTEGRATED REGULATORS

Integrated regulators simplify the High efficiency power conversion.

It can accept an input voltage from 3.5V to 38V, suitable for use in battery-powered applications and power supplies.

To simplify the power-supply design by integrating power elements, feedback circuitry and safety features in a compact chip, here’s presenting the L6981 synchronous step-down regulators that have a high efficiency of 90 per cent. 

Rated to deliver up to 1.5A, 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 a constant switching frequency, minimizing voltage ripple at light loads. 

As the L6981 converters come in two variants optimised for light-load efficiency and noise performance, they both can accept an input voltage from 3.5V to 38V, making them well suited to use in 24V industrial bus-powered applications, 12V and 24V battery-powered equipment, HVAC power supplies, decentralised intelligent nodes, smart sensors and always-on applications. The output voltage can be adjusted from 0.85V 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 

Thermal protection.  

There is also soft-start circuitry that limits inrush current and ensures a constant output voltage slope. An Enable pin permits power-up/power-down sequencing and allows a synchronising clock signal to be applied to the L6981N low-noise converters.  

The L6981 is in production now and available from STMicroelectronics, in the proven, rugged SO8L package. The STEVAL-L6981CDR evaluation board for the low-current converter and STEVAL-L6981NDR for the low-noise version are also available to help designers accelerate device selection in power-supply development.