Editing Automatic test equipment (section)

===Test parameter requirements vs test time===
Not all devices are tested equally. Testing adds costs, so low-cost components are rarely tested completely, whereas medical or high costs components (where reliability is important) are frequently tested.

But testing the device for all parameters may or may not be required depending on the device functionality and end user. For example, if the device finds application in medical or life-saving products then many of its parameters must be tested, and some of the parameters must be guaranteed. But deciding on the parameters to be tested is a complex decision based on cost vs yield. If the device is a complex digital device, with thousands of gates, then test fault coverage has to be calculated. Here again, the decision is complex based on test economics, based on frequency, number and type of I/Os in the device and the end-use application...