Recommended sample size of ESD and surge immunity tests

ESD and surge tests are generally performed with a too small sample size: often even with only one single product. This paper presents a methodology on relating confidence level versus compliance level as function of sample size and test outcome. It is recommended to use seven products for each test. When all seven pass the test, this gives 80 % confidence that 80 % of all products comply with the specification. Guidelines are presented for evaluating test results for different sample sizes and different number of failures.