Can the rise time be calculated by specific formula?

Technical Questions
#1

Hi everyone,

I am wondering that the ESD HBM discharge rise time will below than 2-10 ns in real world(if R and C is variable)?
The standard simulate HBM model with R=1.5 kohms, C=200 pf, and limit the rise time between 2ns-10ns. Can the rise time be calculated by specific formula?

Kindly advise, thank you.

Bruce

#2

Hi Bruce,

This response will not answer the question directly as there are numerous variables in a real-world HBM like discharge that influence the rise-time of the discharge pulse. It may be possible to simulate and estimate better in a “spice model” or some other program like that but even with that the rise time formula would be difficult at best. The resistance between the contacting bodies, approach speed, environmental conditions (temperature and relative humidity/dew point) need to be specified to predict the discharge pulse characteristics. The HBM model only takes into account the temperature and humidity as the contact resistance and approach speed are essentially “0”.

However, the HBM waveform used in reliability testing of ESD sensitive devices is a standardized waveform that allows quantification of an officially accepted robustness for qualification purposes. While there is no assertion that the HBM waveform replicates exactly the pulse resulting from a human touching a device pin with some other pin grounded, the HBM test does provide a time-honored measure for the robustness of a semiconductor device.

#3

Hi EOS-ESD-Association,

Thanks for your reply!

Bruce