Hi team
There are some issues occur of LMX2571 when customer's engineer test ESD.
- Performing the ESD test at the accessory interface of Walkie talkie， After many times +/- 8KV touching ESD test when walkie talkie in standby mode，machine works normal。
- Performing the same ESD test at the accessory interface（the accessory interface don’t connect with LMX2571 directly expect GND. And the interface has put ESD protection diode）When pushed PTT at the same time（meaning walkie talkie is in transmitting mode continuously ）. Repeat test many times, the LMX2571 will lose lock probabilistically，and the lose lock will recovery after walkie-talkie restar。
- Does not restart the walkie-talkie after the lock-out phenomenon occurs。Just POR LMX2571 by MCU，lose lock recovery，walkie-talkie works normal。It can be determined that the LMX2571 is affected by the ESD test when the is transmitting mode continuously.
- Adding some software evasion strategies do the same ESD testing , it was found that the lock loss disappeared under the analog channel. When switching to the digital channel, perform an ESD test with 8KV/air 15KV contact on the accessory interface, the lock will still be lost, and the restart LMX2571 will return to normal
There are some questions
- There is any difference of LMX2571 between standby mode and transmitting mode continuously ？
- Is there any difference of LMX2571’s ESD protection ability at these two modes？why LMX2571 is effected at PPT mode, but it works normal at standby mode?
- what is the difference between the internal principles of our LMX2571 working in analog and digital; why the digital channel will lose lock after ESD?
