Question 6.1: A pulse of 4500 V is discharged from a person into a p-n jun...
A pulse of 4500 V is discharged from a person into a p-n junction. The junction area is 5×10^{-7}cm^{2} and the resistance is 20 \Omega. Assume that the voltage across the device is negligible compared with that of the ESD pulse.
a. Over what time span does the discharge occur?
b. What is the maximum current?
c. Calculate the power density discharged through the diode.
a. For the human body model the time constant is \tau=C_{B}\left(R_{T}+R_{B}\right). Substituting, \tau=100×10^{-2}\left( 10+1500\right)=0.152 \mu s. Therefore, 5\tau=0.76 \mu s.
b. Ohm’s law simply states that i_{o}=V_{HBM}/\left(R_{T}+R_{B}\right)=4500/\left( 20+ 1500\right) = 2.96 A.
c. The power density is \lt p\gt /A_{o}, or R_{T} i_{o}^{2}/\left( 10 A_{o}\right). Substituting, \lt p\gt /A_{o}=20\left(2.96\right)^{2}/\left[10\left( 5×10^{-7}\right)\right]=35 MW /cm^{2}.