ADS1293: Too much noise while using ADS1293 connecting Test signals to the 2nd channel.

Pedro Ulhoa

Part Number: ADS1293

Hi! I am using ADS1293 to measure biosignals. When I am connecting the Test Signal in the 2nd channel, appears that there is too much noise in the signal (screenshot attached). If the test signal is connected internally in the ADS1293, is it correct to assume that there are problems with my power supply rail? or any reference voltage...

Details: The y-axis of the plot is in ADC values. I am doing the Zero test in channel 2. My register configuration is:

over 2 years ago

0 ChienChun Yang over 2 years ago

TI__Mastermind 19815 points

Hi,

I will try to get back to you by 3/3.

Thanks

+1 ChienChun Yang over 2 years ago in reply to ChienChun Yang

TI__Mastermind 19815 points

Hi,

"If the test signal is connected internally in the ADS1293, is it correct to assume that there are problems with my power supply rail? "

Definitely check the power rail. E.g. what is the power supply source to the AVDD? and its ripple? any noise decoupling/bypass capacitors?

--------

can you try the internal test signal and see how/whether there is any significant noises?

e.g. Figure 33. FLEX_CH1_CN: Flex Routing Switch Control For Channel 1

[7:6] TST1

01: Connect channel one to positive test signal

10: Connect channel one to negative test signal

11: Connect channel one to zero test signal

8.3.3 Test Mode

and/or

"For test purposes, the flexible routing switch can short the differential input pins of a channel or connect a differential reference signal to the input of a channel."

Figure 17. Flexible Routing Switch for Channel 1

0 Pedro Ulhoa over 2 years ago in reply to ChienChun Yang

Prodigy 60 points

Hi! Thanks for the reply! It was a bad soldering in the ADS CVREF pin, Now it is working!

0 ChienChun Yang over 2 years ago in reply to Pedro Ulhoa

TI__Mastermind 19815 points

Thanks. Glad you checked and found out.

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ADS1293: Too much noise while using ADS1293 connecting Test signals to the 2nd channel.