Q
What type of passive filters can be added to the output of a linear regulator
without causing instability?
A
Modern internally compensated LDOs are surprisingly robust when it comes to
adding external filtering at the output to reduce noise. Adding small ferrite
beads to suppress high frequency noise is a common practice and usually does
not require any additional circuitry if the inductance of the bead is less than
a few hundred nH. If a real inductor or a high inductance bead is used, a
simple RC damping network at the output of the filter is recommended to prevent
ringing or noise peaking.
