cdm

In earlier articles in this publication we have discussed the charged device model (CDM) testing of small devices. In the first article we demonstrated that the peak current for small devices does not become vanishingly small.¹ The commonly held belief of vanishing current for small devices was shown to be an artifact of measuring the current with the 1 GHz oscilloscope² specified in the JEDEC CDM standard.⁶ The second article explained various ways to make CDM testing of small devices more reliable with the use of small surrogate packages, or the use of templates to hold the device during testing.³ In this article we will show how insight can be gained into the CDM testing of small devices using a simple three capacitor circuit model.^{4, 5}