Effect of Radiated Field Due to ESD on Ones and Zeroes of the Serial Data Stream

The circu it with an output of specified serial data stream has been exposed to the radiated electro magnetic fields generated by indirect discharge from the ElectroStatic Discharge (ESD) simulator. The circu it malfunctioned at a distance of 35 cm fro m the point of discharge. The ESD transient pulse introduced affected only the data stream and binary counter Integrated Circuit (IC) SN74LS393N was found to be malfunctioning. The counter IC passed the parameter test but failed functionally as all the output pins were malfunctioning. The circu it that failed did not have decoupling capacitors connected to the Vcc supply. Another circu it designed with decoupling capacitors connected to the Vcc supply of all the IC's has been exposed to indirect ESD air d ischarge. The effect of the ESD transient pulse on the ones and zeroes of the specified data stream has been observed. The amplitude of the serial data stream has been affected but the order of transmission of the bits has not changed. If the change in amplitude is greater than the set threshold then the order of transmission of bits can change and this becomes crit ical for sensitive circuits where the set threshold is very small. The decoupling capacitors provided protection against any malfunction of the integrated circuits