Hi, my issue is: I made several PCBs and used MCU to get the ECG data, it is strange that each PCB's situation is not same , some work normal at the beginning, i can see the ECG waveform on our own UI screen,and after several (may be in one minute) the waveform disappeared and the ADS1298 didn't transform the data,some didn't work at all ,by the way ,these PCB is not my first batch PCB , I used to make a group of pcb which can work stably for a long time ,the difference between the two group PCB is : 1. the new pcbs i used internal clock instead of external clock (used in the first group pcbs) because i feel the external crystal is too big 2.some trace i don't widen like i did in the old one (as i described yesterday ) . I can find any other reasons except these two difference . There is other question i want to ask is i have tested the normal PCBs for some time and i found that occasionally some abnormal signal would be appeared on our UI screen like the below picture, i asked the similar question in march ,you answer me at the that time is that use the integrated RLD amplifier to improve the common-Mode Rejection . I want to know is it strongly necessary and effective to add a Drive Amplifier to aviod this problem ? because our company want develop a ECG holter which can record the patients ECG signals in real-time and meanwhile the product must be portable or wearable ,add one component means add cost , volume and power consumption.
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