Rail voltages are getting smaller, and tolerances are decreasing. As a result, making accurate power rail measurements has become much more difficult. In the past, any scope was able to measure ripple on historical 5 V rails with 10% tolerance, since the 500 mV requirement was well above the noise level of the scope.
Industry dynamics are driving both a decrease in rail voltage values as well as tighter tolerances across a wide range of rails. Making an accurate ripple measurement on a 1 V rail with 2% tolerance, for example, is difficult on all scopes. This guide describes five tips for making accurate power integrity measurements with oscilloscopes.