LTSpice failed during LTM4644 sim

Question

I ran into an interesting error while doing a hardware to model correlation on the LTM4644 using LTSpice (v17.1.6). It&rsquo;s not really a concern for me but I thought you might want to look into it. 
 I used an LTM4644 to generate the 3.3V supply for an ECAT tester with a 100nF on the Track/SS pin for a soft-start time of about 24ms. Our ECAT contract manufacturer had high fall out on one of the DUT components. The supplier asked them to increase the ramp rate to <1ms. I chose 2.2nF and the C.M. reported major ringing on the LTM4644 output. It turned out that during the rework, the tech removed the COMP cap first, realized the mistake but replaced it with 100nF. I decided to try to run an LTSpice sim to confirm that this caused the ringing. The sim result starts to match the measured signal but then starts to fail at about 2.5ms then collapses at about 3.2 ms.

PaulDaria · Accepted Answer

Hi JimTM , 
 
 Here's a response I get from the developer team. 
 
 "I checked the corresponding code. There is nothing special in there, it should work. Google drive is known to lock files during sync. That may cause problems. Recommend to pause google drive for saving.". 
 
 I suppose the problem is caused by google drive itself. 
 
 Thanks. 
 
 Regards, 
 PaulDaria)

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LTSpice failed during LTM4644 sim