Setting the Stage for On-Die Power-Rail Measurements

Figure 1: Measuring on-die Vdd rail noise requires
a suitably instrumented die and package

Armed with a suitable oscilloscope and active voltage-rail probe, you're now ready to make some power-rail measurements on a semiconductor die. Of course, making measurements on a die is a little different than making measurements on a printed-circuit board. This is where careful design-for-test at the die level comes in, because the chip, its packaging, and the board on which it will be mounted must be instrumented so as to make the on-die measurements possible.