Shorten Electrical Test Time with Double Ramping Test Method

Abstract

The basic principle of double ramping test method involves ramping two voltages at different slew rate measuring the threshold and calculates the delay time at the same test setup. The test method available at present are performed in two separate stages which cause a longer test time and require different type of instrument, example using analog and high speed digital instruments. Analog instrument is used for obtaining the threshold while high speed digital instrument is used for fast ramp at input pin. In this project, the relation of threshold voltage and delay time was studied. Voltage regulator TLE7278-2 was chosen for this study. This method was found to be an efficient method in performing threshold and delay time tests. One time test setup was sufficient to obtain two test results. This shortens the required test time, at the same time provide good repeatability measurement. As a result, the test time was shortened by more than 5%. It is evident from the findings that double ramping test method resulted shorter test time in obtaining the threshold voltage and delay time. On top of that, it will spare some unused digital instrument and provide more flexibility for higher test parallelism.