Shmoo plot: Difference between revisions

Revision as of 14:12, 13 June 2015

Revision as of 09:35, 1 May 2016

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For example, when testing [[semiconductor]] [[memory]]: [[voltage]]s, [[temperature]], and [[refresh rate]]s can be varied over specified ranges and only certain combinations of these factors will allow the device to operate. Plotted on independent axes (voltage, temperature, refresh rates), the range of working values will enclose a three-dimensional, usually oddly-shaped volume. Other examples of conditions and inputs that can be varied include [[frequency]], [[temperature]], timing parameters, system- or component-specific variables, and even varying knobs tweakable during [[silicon chip fabrication]] producing parts of varying quality which are then used in the process.

Often one 'knob' or variable is plotted on one axis against another knob or variable on another axis, producing a two -dimensional graph. This allows the test engineer to visually observe the operating ranges of the device under test. This process of varying the conditions and inputs to the component or system may sometimes be referred to as 'shmooing' but more officially known as electrical testing or qualification. [[Automatic test equipment]] often contains software features that allow automated shmooing of a part.

== Origin ==

The Shmooshmoo Plotplot was invented by VLSI Hall Of Fame inductee [[Robert Huston]].

== Etymology ==

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== Examples ==

Automated test equipment have traditionally generated a 2two-dimensional, [[ASCII]] form of the shmoo plot that uses an "X" to represent functional points and blank space for non-functional points.

[[File:64K DRAM Shmoo Plot-typical.png|thumb|left|Normal shmoo plot]]