Worst Case Analysis Calculation

Thread Starter


Joined Oct 26, 2017
Hello all,

I have attached a file in which I have performed the Worst Case Analysis calculation for a simple active low circuit.

The input is Active low and the output of the circuit is given to a microcontroller pin which has a Vil=1.2V
The input is Active low = 0V

And I have calculated this, with three voltage conditions.vIGN = 6.5V , 13.5V and 16.5V.
You can check my formulas in the cell.

I have taken the forward voltage of the diode from the datasheet of the diode BAS21 from Onsemi for a maximum of 14mA.

Can someone please check whether my calculations (Voltage drops, and current through the resistor and power dissipation) are correct?
I have also considered injection current. The microcontroller pin has internal clamping diodes which I have assumed to be 0.6V drop. I have also attached the circuit in the excel sheet.
Please help if my calculations are wrong.
Thanks in advance.