STMicroelectronics – 36V synchronous step-down switching regulator supplies up to 400mA to the load


The L6984 from STMicroelectronics is a step-down monolithic switching regulator which can supply as much as 400mA to the load.

The L6984’s output voltage is highly adjustable down to as low as 0.9V. It operates from a wide input-voltage range of 4.5V to 36V.

The device can implement both a Low Consumption Mode (LCM) and a Low Noise Mode (LNM). The LCM maximises efficiency at light loads, while keeping the output-voltage ripple low. In LNM the switching frequency is almost constant over the load-current range, enabling noise-sensitive applications to easily filter out switching noise.


The Power Good open-collector output can implement output-voltage sequencing during the power-up phase.

The synchronous-rectification control scheme, which offers high efficiency at medium and heavy loads, together with the capability to switch at high frequency, helps to keep the size of power circuits based on the L6984 small.

Pulse-by-pulse current sensing on the low side is provided for effective constant-current protection.


  • 13μA shut-down current
  • Adjustable switching-frequency range: 250kHz to 600kHz
  • Thermal shut-down protection
  • Constant on-time control scheme


  • Automotive systems
  • Battery-powered applications
  • Car audio
  • Sensors
  • Metering equipment


This evaluation board features a single L6984 switching regulator.

Orderable Part Number: STEVAL-ISA159V1