JESD22-A115 is a reference document; it is not a requirement per JESD47 (Stress Test Driven Qualification of Integrated Circuits). Machine Model as described in JESD22-A115 should not be used as a requirement for integrated circuit ESD qualification. Only human-body model (HBM) and charged-device model (CDM) are the necessary ESD qualification test methods as specified in JESD47.