ESD testing of head stack assemblies used in magnetic recording hard disk drives

ESD testing of the head stack assembly (HSA) used in hard disk drives is described. Testing using an IEC 801-2 simulator as well as a field induced model are described. Results show that giant magnetoresistive (GMR) heads can be magnetically damaged at voltages as low as 150 V using an ESD gun. GMR heads on an HSA can be damaged magnetically and their resistance can be increased, in spite of the fact that the preamplifier is between the GMR heads and the connector. It is concluded that it is important and interesting to conduct ESD testing of head stack assembles and that some HSA designs may require some degree of ESD control in a manufacturing environment if ESD damage is to be avoided.