Ceramic capacitors offer low cost, small size, and can offer improved reliability over tantalum and aluminum capacitors. The ultra-low ESR attribute of ceramic capacitors, however, does effect choice of LDO when used at the output as most older LDOs require the ESR of a capacitor on its output for loop stability. Although almost all newer designs include loop compensation so that they can be used with ceramic capacitors, there’s still hope for ones favorite older workhorse LDO (or dirt cheap). Simply add a small resistance in series with desired ceramic capacitor.
The region of stability is shown in the graph above (in this case for a TC1017). Any decent datasheet will provide this graph. Selecting the lowest value for the ESR, while keeping in mind resistor tolerance, is best to minimize load transients.
Figure 1 Region of Stability of ESR vs Load Current
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