L6984 – 36V, 400mA Step-Down Switching Regulator | STMicroelectronics

Product Description:

The L6984 by STMicroelectronics is a step-down monolithic switching regulator capable of delivering up to 400 mA DC output current. Operating from an input voltage range of 4.5 V to 36 V, it offers an adjustable output voltage starting from 0.9 V. For a fixed 3.3 V output, no external resistor divider is required.

Designed for energy-sensitive automotive applications, the L6984 features two operating modes:

• Low Consumption Mode (LCM) for maximizing efficiency during light-load conditions, perfect for systems active during car parking.

• Low Noise Mode (LNM) to maintain a nearly constant switching frequency across varying loads, ideal for low-noise applications such as car audio and sensors.

The L6984 also features a PGOOD open collector output to facilitate output voltage sequencing during power-up. It incorporates synchronous rectification to ensure high efficiency at medium to heavy loads and a high switching frequency (adjustable from 250 kHz to 600 kHz), enabling compact application designs.

Its pulse-by-pulse current sensing on the low-side power element ensures reliable constant current protection, while built-in thermal shutdown protects against overheating.

Features:

• 400 mA DC output current

• 4.5 V to 36 V operating input voltage range

• Synchronous rectification for higher efficiency

• Selectable Low Consumption Mode (LCM) or Low Noise Mode (LNM)

• 75 μA quiescent current at light load (LCM, VOUT = 3.3 V)

• 13 μA shutdown current

• Adjustable switching frequency from 250 kHz to 600 kHz

• Output voltage adjustable from 0.9 V

• No external divider required for fixed 3.3 V VOUT

• VBIAS for enhanced efficiency at light load

• 350 mA valley current limit

• Constant on-time control

• Power Good (PGOOD) open collector output

• Integrated thermal shutdown protection

Applications:

• Automotive electronics (car parking systems, infotainment, sensors)

• Industrial control systems

• Battery-powered systems

• Consumer electronics requiring compact and efficient DC-DC converters