MIC4722 datasheet(17/20 Pages) MICREL

17 / 20 page

Micrel, Inc.

MIC4722

September 2007

M9999-090507-B

Ripple measurements

To properly measure ripple on either input or output of a

switching regulator, a proper ring in tip measurement is

required. Standard oscilloscope probes come with a

grounding clip, or a long wire with an alligator clip.

Unfortunately, for high frequency measurements, this

ground clip can pick-up high frequency noise and

erroneously inject it into the measured output ripple.

The standard evaluation board accommodates a home

made version by providing probe points for both the

input and output supplies and their respective grounds.

This requires the removing of the oscilloscope probe

sheath and ground clip from a standard oscilloscope

probe and wrapping a non-shielded bus wire around the

oscilloscope probe. If there does not happen to be any

non shielded bus wire immediately available, the leads

from axial resistors will work.

By maintaining the

shortest possible ground lengths on the oscilloscope

probe, true ripple measurements can be obtained.

MIC4722 Datasheet(PDF) 17 Page - Micrel Semiconductor