Other Parts Discussed in Thread: TIC12400-Q1
Dear team,
This is Chris from TI Korea and one of my customers is going through an error that happened during ESD test with the switching IC. I explained in detail about the current situation, possible reasons and the questions.
1. Issue : As the picture below, when air discharge +15kV (ICU powered-up) is applied to fuse at ICU, the switching IC doesn't work. (Doesn't work with input switch).
※Switching IC : TIC10024-Q1
2.Possible reason : When ESD is applied, noise could be possibly applied to digital block in the switching IC and HW reset pin has been triggered.
Situation - 1) After the switching IC stops working, it works fine again after the battery reset.
2) After ESD is applied, the register settings are reset at the switching IC.
3) Works properly when ESD is directly applied to the input of switching IC.
4) Increasing resistance and capacitor at switching input doesn't solve the issue.
3.Ongoing process : When serial resistor value at SPI communication line is increased from 100ohm to 390ohm, the issue is resolved.
→ IF there is not problem with ICU function evaluation and SPI waveforms, this solution will be selected to solve the issue.
→ After resistor is increased to 390ohm, there is no issue with the ICU function evaluation.
4. Questions : 1) Could possible noise in SPI communication line reset the IC's register settings? (or trigger HW reset pin)?
2) After reviewing the SPI waveform with 390ohm serial resistor, most values qualify the SPI timing parameters on datasheet, but some parameters exceed the SPI timing parameters on datasheet. Could there be possible problems with functioning or performance? (Please refer to the waveform below).
- t_F_CS = 30.5ns
- t_VALID = 97.2ns
3) Are there other possible reasons to this issue other than trigger in HW reset pin?
4) Are the read timings (Switching IC reads MOSI signal) and the read timings(MCU reads MISO) appropriate with the SCLK's falling edge?
