Compact 60V DC/DC converters have dynamic mode selection for low noise
Dynamic mode selection in the L7983 DC/DC buck converter satisfies noise-sensitive applications and maximises efficiency at light load. The STMicroelectronics’ L7983 is a compact, 3.0 to 60V, 300mA synchronous DC/DC buck converter which allows 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 efficiency while powering low or idle loads. The mode is selected using an external pin that can be controlled dynamically by the application or pre-set by tying high or low.
The wide input voltage range of the L7983 allows it to operate from 12V and 24V industrial buses with a generous safety margin, says ST. The L7983 is also suited to battery-powered applications and can be used in industrial fail-safe systems, decentralised intelligent nodes, appliances, robotics, telecomms equipment, and precision-sensing applications that leverage the low noise mode.
The L7983 enhances design flexibility by allowing a wide switching-frequency range of 200kHz to 2MHz. Optional spread-spectrum dithering helps minimise electromagnetic interference (EMI). Drawing quiescent current of 10 microA, the converter has minimal impact on system power demand and provides an external Enable pin that reduces the current to just 2.3 microA in shutdown mode.
Additional features include support for power sequencing and synchronisation to an external clock. Built-in safety and protection include soft-start, over-temperature protection, current limiting with pulse-by-pulse sensing, over-voltage protection, and adjustable under-voltage lockout (UVLO) according to the input voltage. There is also integrated compensation circuitry that simplifies design and saves bill of materials (BoM) costs.
Three L7983 variants are available: the L7983PU33R with 3.3V fixed output voltage, L7983PU50R with 5.0V fixed output voltage, and L7983PUR with adjustable output voltage.
An associated evaluation board is available for each DC/DC buck converter. The STEVAL-L7983V33 accelerates design with the L7983PU33R. The STEVAL-L7983V50 and STEVAL-L7983ADJ support the L7983PU50R and L7983PUR respectively.
The L7983 is in production now and available in a 3.0 x 3.0mm DFN10 package.
