CCS/ADS8861: DAQ_ADS8861

Carlos Martins81

Part Number: ADS8861
Other Parts Discussed in Thread: TIPD115

Tool/software: Code Composer Studio

Hello,

I'm working with ADS8861 on a project to acquire analog variables.
As a test, I am converting a 50 Hz signal with a sampling frequency of 5 kHz. There is a problem, the converted signal that does not match the signal coming into the ADC.

Can you help me with this problem?

Attached like my simulations, the SPI diagram of a conversion and the final result.

Greetings,
Carlos Martins

over 6 years ago

0 Carlos Martins81 over 6 years ago

Intellectual 450 points

Sorry,
I forgot to mention any information.
I am using 4-wire SPI mode without buzy with a clock frequency of 16 MHz, PL = 0 and PH = 0.
The SS signal in my diagram is the CONVST signal.

0 Evan Sawyer over 6 years ago in reply to Carlos Martins81

TI__Expert 3175 points

Hi Carlos,

I am looking into this and will get back to you soon.

0 Evan Sawyer over 6 years ago in reply to Evan Sawyer

TI__Expert 3175 points

Hi Carlos,

To use this amplifier as a buffer, the input and feedback resistors must be the same. Figure 73 in the ADS8861 datasheet shows an example input driver.

We also have a reference design for a similar device, which can be found here (or search for TIPD115).

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CCS/ADS8861: DAQ_ADS8861