ESD测试.ppt

EUT表面涂漆 If the coating is not declared to be an insulating coating by the equipment manufacturer, then the pointed tip of the generator shall penetrate the coating so as to make contact with the conducting substrate. Coating declared as insulating by the manufacturer shall only be submitted to the air discharge. The contact discharge test shall not be applied to such surfaces. 对EUT表面涂漆的测试方法选用AD/CD（by Manufacture）： ——金属shell表面非绝缘的涂层需要破开涂层进行接触放电 ——金属shell表面以绝缘为目的的涂层不需要破坏，以空气放电进行测试 ——也有客户要求AD/CD两种方法都需要测试 ——一般在非金属表面的导电涂层是肯定不能破坏的，用空气 ——只有在金属表面的绝缘涂层需要判断 About bleeder resistors cable…… The presence of the cable with the bleeder resistors can influence the test results of some equipment. A test with the cable disconnected during the ESD pulse takes precedence over the test with the cable installed during the test, provided that the charge has sufficiently decayed between the successive discharges. 对不接地设备进行辅助排放滞留电荷（也有不使用的情况（对于泄放死的EUT）。 - the time interval between successive discharges shall be extended to the time necessary to allow natural decay of the charge from the EUT; 延长施加时间 sweeping of the EUT with a grounded carbon fibre brush with bleeder resistors (for example, 2 × 470 kΩ) in the grounding cable. 放电纤维刷 NOTE In case of dispute concerning the charge decay, the charge on the EUT can be monitored by a non- contacting electric field meter. When the charge has decayed below 10 % of the initial value, the EUT is considered to be discharged. （判断EUT电荷衰减-不适用，确保EUT运行稳定，听/看） post-installation tests（ situ ESD testing） These post installation tests, which are performed in situ, may be applied when agreed between manufacturer and customer. It has to be considered that other co-located equipment may be unacceptably affected. NOTE In addition, the EUT itself may suffer significant ageing from in situ ESD testing. The mean time to failure (MTTF) of many modern electronic