Other Parts Discussed in Thread: ADS8881
I’m testing the RC charge bucket’s influence to ADS8881, so I changed the R/C value to see it's influence. And I meet some problems after I did the following things:
- Change R19 and R20 from 4.99ohm to 10ohm, 1%, CR0603-16W-10R0FT
- Change C20 from 0.01uF to 22uF, X5R, 6.3V, GRM21BR60J226, 0805 (I set input voltage below 4 Vpp)
Then, I use PSI as the input source, offset= 0V, frequency= 2kHz, the three problems are as follows:
- ADC Code error
If the PSI output Vpp= 3V, the ADS88881 GUI code is only -8550 ~ 8550 (-0.3V to +0.3V)
- Input range Error
If PSI output Vpp > 3.6V, the whole EVM board will power down and three LEDs all tops flashing；
But If PSI output Vpp < 3.5V, this problem won’t appear.
- Capture Error
If 3.2V < PSI output Vpp < 3.5V, after I click “Capture” on the EVM, the whole EVM board will power down and message showed as below:
I think it’s maybe the PHI-EVM board’s reason, so I tested the test point voltage of PHI board. At first I can get the voltage. Then I don’t know why the board is broken.
After I connect the EVM with computer, the LED will flashing. But if I open the GUI, the whole board will power down and problems showed as below. So I can't use the board to do test now.
Looking forward to your reply and I can shipped the board to you if needed.
I asked a little more questions these days, thank you for your patients and help sincerely.
Best regards,
Marc
