2Adc Step-Down Switching Regulator with 4V to 38V InputJuly 23, 2019 by Scott McMahan
The L6986H from STMicroelectronics is a step-down monolithic switching regulator able to deliver up to 2Adc. The output voltage adjustability ranges from 0.85V to Vin. Thanks to the P-channel MOSFET high-side power element, the device features a 100% duty cycle operation. The wide input voltage range of 4V to 38V meets the specification for the 5V, 12V, and 24V power supplies.
ST designed L6986H for 12V and 24V buses, programmable logic controllers (PLCs), decentralized intelligent nodes, sensors, and low noise applications. According to the company, the combination of synchronous rectification, designed for high efficiency at medium to heavy loads and the high switching frequency capability make applications using the device compact.
The "low consumption mode" (LCM) is for applications active during idle mode. It maximizes the efficiency at light-load with controlled output voltage ripple.
The "low noise mode" makes the switching frequency constant and minimizes the output voltage ripple overload current range, thereby meeting the low noise application specifications.
An output voltage supervisor manages the reset phase for any digital load (µC, FPGA). The RST open collector output can also implement output voltage sequencing during the power-up phase.
Pulse by pulse current sensing on both power elements effectively achieves constant current protection.
- 2Adc output current
- 4V to 38V operating input voltage
- Low consumption mode or low noise mode
- 30µA IQ at light-load (LCM VOUT = 3.3V)
- 8µA IQ-SHTDWN
- Adjustable fSW (250kHz to 2MHz)
- Fixed output voltage (3.3V and 5V) or adjustable from 0.85V to Vin
- Embedded output voltage supervisor
- Adjustable soft-start time
- Internal current limiting
- Over-voltage protection
- Output voltage sequencing
- Peak current mode architecture
- RDS(on) HS = 180mΩ, RDS(on) LS = 150mΩ
- Thermal shutdown