Shmoo Plot

Shmoo plotting in ETSNT is powerful for characterization and failure analysis. The concept of Shmoo Plotting is to “sweep” a system resource across a defined range to see how the Dut behaves. For example, if you wish to see how your Dut performs at higher speeds you could repeatedly increase the Test Rate in Run Setup and click RUN. But with Shmoo, you could vary the Internal Clock from say, 1MHz to 2MHz in 25KHz steps and run a plot. With a simple click of a button you will have performed 40 manual tasks, and see the results of each task clearly!

With Shmoo, you can plot any of the following parameters against any other:

Delay Generators - All pins using the specified Delay will be affected
Dut Power Supplies - Change Vcc or voltage references on your Dut
Logic Levels - Vary Hi, Lo or Threshold levels on specific pins
Programmable Loads - Watch your part respond to increasing loads
Internal Clock - Quickly find FMAX

You can also have hidden variables. If you set Logic Levels to be a percentage of Vcc, then the relationship between Dut Power and your logic levels will be maintained during a Shmoo of the related Dut Power Supply. Similarly, setting up Delays as a percentage of the Internal Clock will insure a consistent timing relationship between pins at any Test Rate selection, thus yielding very accurate FMAX measurements. In addition, if you are using more than one Dut supply you can use the Multipower feature to define how each supply will be affected by the plot. Here's how we setup for the plot:

shmoo setup

After setup, we start plotting with the "Plot" button:

animated shmoo

(Note: This animated GIF is only 45K... you'll enjoy it!)
Hit your "Back" button when you've finished watching the plot.