Hi,
The TPS65265 datasheet mentions that the LX node cannot go below -1V even during short transients. However in our Board, all three LX nodes are going below -1V (around -1.8V) for a very short period (5ns or less). Will this cause problem in our Regulator IC?
I have attached the waveforms with this query. You can notice that during MOSFET ON state, there is -1.8V Negative transient for very short period followed by -400mV for about 20ns (I suspect this drop is due to Body diode conduction during Deadtime) followed by 0V. So basically there are two transients - a short negative spike followed by a relatively long Body diode drop. Do you think the Short spike might be due to Oscilloscope probes (we have used Minimal Ground Loop probe, but still some Loop exists) or is it a real problem? There are no significant spike in Positive direction at OFF period though.
Should we be worried about this negative spike?
Below are the Specs of the regulator
Input Voltage - 12V
Output Voltage - 1.8/1.35/2.5V
Load current - 2.5/0.5/0.7A
Output Inductor - 4.7u/10u/10u
Output Capacitor - 94u/47u/47u (ceramic)
Switching frequency - 500KHz
Operating mode - PSM, No External clock
