ESD Sensitivity (ESDS) Testing Waveforms

 

The various models used for testing a device's ESD sensitivity (ESDS) level, i.e., HBM, CDM, and MM, apply standard waveforms to electrically stress the device under ESD testing.  These waveforms are usually defined by their peak current level, rise and fall times, and duration. Figures 1 to 3 below show the various waveforms used in HBM, CDM, and MM testing, respectively.

           

During HBM ESD testing, the HBM test circuit must apply a pulse that meets the requirements shown in Figure 1. The rise time of the HBM ESD pulse, tR, which is measured between the time the pulse reaches 10% of its peak current to the time the pulse reaches 90% of its peak current, must be between 5 to 9 nanoseconds long on the average.  On the other hand, the time delay tD, which is the time it takes for the pulse to decay from 100% to 37% of its peak current, must be 150 +/- 20 nanoseconds long. The HBM pulse peak current at 400 V must be 0.27 +/- 10% A.

                 

                

Figure 1. Stress Waveform Used for HBM ESD Testing

    

                      

During MM ESD testing, the MM test circuit must apply a damped sinusoidal signal (~12 MHz) that meets the requirements shown in Figure 2. The rise time of the MM ESD pulse, tR, must be between 6 to 8 nanoseconds long on the average.  The MM peak current at 400 V must be 5.8 +/- 20% A.

                 

  

Figure 2. Stress Waveform Used for MM ESD Testing

                

     

During CDM ESD testing, the CDM test circuit must apply a pulse that meets the requirements shown in Figure 3. The rise time of the CDM ESD pulse, tR, must be between 300 to 500 picoseconds long.  On the other hand, the time delay tD, which is the time between the rising 50% peak current point and the decaying 50% peak current point of the pulse, must be 0.5-1.5 nanoseconds long on the average. The CDM peak current at 400 V must be 2.1 +/- 20% A.

                 

               

Figure 3. Stress Waveform Used for CDM ESD Testing

      

See also:   What is ESD?ESD ModelsESDS LevelsESD FailuresESD Standards

ESD Controls ESD Audit ChecklistThe Triboelectric Series

   

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