The DC-DC converters are very common, and they are generally a cheaper solution for most devices.
there is Two commonly terms of DC-DC converters are non-isolated and isolated converters
Both the isolated and non-isolated converters have their uses, the customer should choose the right one depend on the application and individual needs.
Isolated DC/DC Converters: the parts have the internal transformers that will transform the input to a different output voltage for use with your equipment. With this converter, the output is isolated from the input.
Isolation prevents input voltage from transmitting to the output in case of internal failure.
They are useful for negative or positive grounds, and they can also be used as a floating ground for different types of equipment, such as telecommunications equipment.
main disadvantage of isolated dc-dc converter is circuit becomes bulky & transformer losses will also add that will decrease the efficiency.
Non-Isolated DC/DC Converters: the parts do not have any dielectric isolation between the input and output circuit.
They are typically used for smaller voltages. They can step the voltage up or down,
and some of the converters have the ability to do either.
Non-isolated DC/DC converters are common with lower cost , and used in most negative ground applications in vehicles for various DC powered appliances and equipment.