mrblueblue1234
Junior Member level 1
Hello everyone!
While doing electrostatic discharge (ESD) testing, it seems that noise is coupling into the MR pin
of the TPS3823 causing my microcontroller to be reset. I took a 0.22 uF capacitor and soldered this between pins 3 (MR) and 2 (GND) and now I am not seeing the unexpected resets during an electrostatic discharge.
Here is a screen shot of the circuit:
I was wondering if there is a better value to use for the capacitor? The 2k resistor (R200) and the added
capacitor should give a low pass cutoff frequency of:
f = 1/ (2 * pi* 2k * 0.22 uF ) = 361 Hz
1.) When solving ESD problems how should I be thinking about the low pass filter here? Should I try to move as close as possible to DC? (0 Hz for the cutoff?)
2.) What about the impedance of the capacitor? We know that the impedance for a capacitor is
Zc = 1 / (j*w*C)
As frequency gets larger the impedance of the capacitor decreases routing noise to ground.
If I had my choice between difference values of capacitors such as 0.68 uF, 22 uF or 47 uF what would be the best
selection for this problem I am having with the TPS3823.
Thank you.
While doing electrostatic discharge (ESD) testing, it seems that noise is coupling into the MR pin
of the TPS3823 causing my microcontroller to be reset. I took a 0.22 uF capacitor and soldered this between pins 3 (MR) and 2 (GND) and now I am not seeing the unexpected resets during an electrostatic discharge.
Here is a screen shot of the circuit:
I was wondering if there is a better value to use for the capacitor? The 2k resistor (R200) and the added
capacitor should give a low pass cutoff frequency of:
f = 1/ (2 * pi* 2k * 0.22 uF ) = 361 Hz
1.) When solving ESD problems how should I be thinking about the low pass filter here? Should I try to move as close as possible to DC? (0 Hz for the cutoff?)
2.) What about the impedance of the capacitor? We know that the impedance for a capacitor is
Zc = 1 / (j*w*C)
As frequency gets larger the impedance of the capacitor decreases routing noise to ground.
If I had my choice between difference values of capacitors such as 0.68 uF, 22 uF or 47 uF what would be the best
selection for this problem I am having with the TPS3823.
Thank you.