ESD sensitivity of devices on a charged printed wiring board

We have studied the electrostatic behavior of different kinds of charged printed wiring boards (PWB) in order to assess ESD sensitivity of devices in a discharge of charged PWB (Charged Board Model). Experimental results, with a focus on energy considerations and discharge current, were supported by theoretical analysis including Spice-simulations. ESD energy sensitive devices on a charged PWB could be at risk from ESD failure at lower charge or voltage levels under some conditions than before assembly. Standard MM and HBM test data of devices give information that can be used to assess the risk of ESD damage to components on the PWB in the case of CBM ESD.