test  techniques


the ring oscillator frequency is 10MHz and that its Vss, Vcc, Vccb, and output pads are connected to pins 1, 2, 3, and 4 respectively. Let’s further assume this device requires 5V to power it and 5V to trigger the oscillation.


This article has offered a number of techniques useful for performing ring oscillator measurements with a frequency measurement tool.


© 2012 Angel Business Communications. Permission required.


The ring _ max command listed previously offers a simpler approach to performing this same measurement:


vss _ pin = 1


vcc _ pin = 2 vccb _ pin = 3 output _ pin = 4


vcc = 5.0


Defines the voltages required to power and trigger the ring oscillator.


meas _ status = ring _ Performs the measurement and returns the max(vcc _ pin, vccb _ frequency (in Hz) and amplitude (in Vp-p) of the pin, vss _ pin,


output _ pin, vcc, 10e6, 0.5, 25e-3, frequency, level, meas _ status)


Defines the DUT pins.


strongest signal found. The ring _ max command simplifies things a bit. Although most of the arguments are self-explanatory when compared to the previous example, the 6th, 7th, and 8th


arguments (...10e6, 0.5, 25e-3...) require some explanation:  10e6 is the expected frequency of oscillation.  0.5 is the measurement tolerance. This parameter tells the function how to know that it has measured the desired frequency. The measurement stops when the following condition is met:


 25e-3 is the minimum acceptable signal level in Vp-p.


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www.siliconsemiconductor.net 18 www.siliconsemiconductor.net Issue IV 2012


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