LTC6702 SPICE model issue

Hi GudniMar,

The response seems to be oddly strange, though I can't really say much as I don't see the whole picture of the schematic. As I may suggest:

1. Chech the current of all the inputs, including supply rails of the comparator.
2.  Probe output current as well that is on the load, this might be caused by a certain response in the output.
3. In the image you shared, you can also add IC=0 on the capacitor which may prevent sudden spikes that occurs.

With the hysteresis issue, can you share with us the circuit you are using or a snippet of that so we could assess if this is an internal model issue, if it is, a ticket should be raised for this with the help of the apps engineer involved in this model.

Hope this helps.

Best Regards,

Earl

Hi Earl, thank you for the reply

I've simplified my circuit to mostly only include my screenshot, surprisingly the issue still appears (I didn't expect that to be honest). I've removed ALL capacitors.

It is not 100% repeatable but when the comparator toggling happens it is usually always around the same position on the time axis.

Steps to reproduce:

1. Start simulation

2. Wait for at least 5ms of simulations to be done

3. If issue did not appear, repeat

I can see there are tiny current spikes on both comparator inputs

Below is the comparator output

I can see there is a spike on my power supply, Not sure whether it is due to the comparator model.

Here is the voltage on one of the comparator inputs:

Not sure if it helps, but here are my SPICE settings (should be default as far as I'm aware of):

Here is the simulation file:

Design4.asc

To add more information. I can confirm internal hysteresis seems to be working as expected

If I add 2mVpp SINE with 1mV DC offset on the inverting input => no switching

If I increase the SINE to 3mVpp with 1mV DC offset => Comparator starts switching.

So the problem I'm seeing seems come down to some strange spike / calculation error in the SPICE model?

Hi GudniMar ,

Thank you for the additional information you sent, this will help me further deepen my investigation.

I will come to you as soon as possible, i will look in this.

Thank you for your patience and patronage in using LTspice as your simulation software.

Best Regards.

Earl