Hello,
I would like to use ADS1299 for EEG amplifier. I bought its evaluation kit, seems work perfect. Based on that and my requirements, i designed a PCB and i made two systems based on ADS1299. One of them works perfect, but the other one no. To make a test, i put the first channel on test signal; here are the related parameters and configuration registers:
- VREFP: internal, 4.5V
- VREFN: GND
- AVDD: +5V
- AVSS: GND
- DVDD: 3.3V
- CONFIG1: 0b10010110, osc: 2097152Hz so sample rate = 256
- CONFIG2: 0b11010000, test signal freq= 1Hz, amp: 1 * ( 4.5 – 0 ) / 2.4 mv
- CH1SET: 0b01100101, channel 1 on test signal, PGA gain = 24
So according to these configurations, I should have a 1Hz square wave with +-22.5v amplitude. I have this in one of my PCBs but in the other on the amplitude is not correct, the wave form is noisy and it is shifted down (you can find the ch1 output on the attached pic).
For me most probably it is related to hardware, but both boards are the same. Do you have some idea about this problem, concerning to the output signal, it can steam from with part ?
Thanks in advance
