STMicroelectronics L7983 DC/DC converters

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The STMicroelectronics L7983 is a compact, 3–60 V, 300 mA, synchronous DC/DC buck converter with flexible, dynamic-mode selection to satisfy noise-sensitive applications and maximise efficiency at light load.

Innovations engineered into the converter allow control of the low-side power MOSFET to provide a low-noise mode (LNM) with constant switching frequency and an alternative low-consumption mode (LCM). In LCM, the converter maximises the efficiency while powering low or idle loads. The mode is selected using an external pin that can be controlled dynamically by the application or preset by tying high or low.

With its wide input-voltage range, the product can operate from 12 and 24 V industrial buses with a generous safety margin. It is also suited to battery-powered applications and can be used in industrial fail-safe systems, decentralised intelligent nodes, appliances, robotics, telecom equipment and precision-sensing applications that leverage the easy-to-use low-noise mode.

While the high maximum input voltage ensures robust performance, the product enhances design flexibility by allowing a wide switching-frequency range of 200 kHz to 2 MHz. In addition, optional spread-spectrum dithering helps minimise electromagnetic interference (EMI). Drawing quiescent current of 10 µA, the converter has minimal impact on system power demand and provides an external Enable pin that reduces the current to 2.3 µA in shutdown mode.

Additional features include support for power sequencing and synchronisation to an external clock. Built-in safety and protection include soft-start, overtemperature protection, current limiting with pulse-by-pulse sensing, overvoltage protection and adjustable undervoltage lockout (UVLO) according to the input voltage. There is also integrated compensation circuitry that simplifies design.

Three variants are available, comprising the L7983PU33R with 3.3 V fixed output voltage, L7983PU50R with 5 V fixed output voltage and L7983PUR with adjustable output voltage.

For more information: www.st.com/l7983-pr.