L7983PU33R [STMicroelectronics]

The L7983 device is a step-down monolithic switching regulator able to deliver up to 300 mA DC based on peak current mode architecture.

The output voltage adjustability ranges from 0.85 V to V_IN. The wide input voltage range and adjustable UVLO threshold meet the specification for the 12 V, 24 V and 48 V industrial bus standards.

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 L7983 supports dynamic LCM to LNM transition.

The soft-start time is internally fixed and the output voltage supervisor manages the reset phase for any digital load (microcontroller, FPGA, etc.).

The internal compensation network features high noise immunity, simple design and saves on the component cost.

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.

• 3.5 V to 60 V operating input voltage
• Fixed output voltage (3.3 V and 5 V) or adjustable from 0.85 V to V_IN
• 300 mA DC output current
• Dynamic low consumption mode to low noise mode selection
• 10 µA operating quiescent current (L7983PU33R, V_IN > 24 V, LCM)
• 2.3 µA shutdown current
• 200 kHz to 2.2 MHz programmable switching frequency
• Optional spread spectrum (dithering)
• Internal soft-start
• Enable / adjustable UVLO threshold
• Synchronization to external clock
• Internal compensation network
• Internal current limiting
• Overvoltage protection
• Output voltage sequencing
• Thermal shutdown