Synchronous DC-DC Switching Regulators Handle up to 2A

STMicroelectronics has added the L6986, L6986F and L6985F step-down monolithic switching regulators with synchronous rectification. These devices offer high efficiency with a very low quiescent and a low consumption mode specific for light load conditions.

Available in a space-saving 16-pin HTSSOP package, they come with three different maximum output current capabilities from 0.5 to 2 A while maintaining pin-to-pin compatibility.

The output voltage adjustability ranges from 0.85V to VIN. Thanks to the P-channel MOSFET high-side power element, the device features 100% duty cycle operation. The wide input voltage range meets the specification for the 5 V, 12 V and 24 V power supplies.

Target applications include:

• Designed for 12 V and 24 V buses
• Programmable logic controllers (PLCs)
• Decentralized intelligent nodes
• Sensors and low noise applications (LNM)

The "Low Consumption Mode" (LCM) is designed for applications active during idle mode, so it maximizes the efficiency at light load with controlled output voltage ripple. The "Low Noise Mode" (LNM) makes the switching frequency constant overload current range, meeting the low noise application specification.

The output voltage supervisor manages the reset phase for any digital load (μC, FPGA, etc.). The RST open collector output can also implement output voltage sequencing during the power-up phase.

The synchronous rectification, designed for high efficiency at medium - heavy load, and the high switching frequency capability make the size of the application compact. Pulse by pulse current sensing on both power elements implements an effective constant current protection.

Key Features

• 2A dc output current
• 4V to 38V operating input voltage
• Low consumption mode or low noise mode
• 30µA IQ at light load (LCM VOUT = 3.3 V)
• 8µA IQ-SHTDWN
• Adjustable fSW (250kHz - 2MHz)
• Output voltage adjustable from 0.85V to VIN
• Embedded output voltage supervisor
• Synchronization
• Adjustable soft-start time
• Internal current limiting
• Overvoltage protection
• Output voltage sequencing
• Peak current mode architecture
• RDSON HS = 180mΩ, RDSON LS = 150mΩ
• Thermal shutdown