0
\$\begingroup\$

First has anyone used this chip ADS1216 and the IDAC feature on the chip?

I have tried on many occasions to get the IDAC's to work on the ADS1216 and I'm not successful. I'm using an FPGA (artix-7 w/ Vivado 2016.4) to interface with the ADS1216.

I have setup the setup reg on the ADS1216 to use the internal reference and I have also set the range for the IDAC and I have also given the ADS1216s' IDAC a value. After all that I still see no current on the IDAC. I have to use the IDAC's because I'm using and 4 wire temp sensor that requires a current supply.

What do I need to do to get the IDAC to function?

\$\endgroup\$
0
\$\begingroup\$

TI chips are complex usually with two or three registers that need to be set before any operation happens.

Since you haven't added any info on your setup OR your register settings, I'll assume the worst.

Make sure these things are happening:
1) That your measuring current with a low impedance pathway (like 20k to 150k). I don't think your doing this but just know what the load is on the DAC.

2) Set the ACR range register to max current (which is 3)

3) Make sure the REF_EN pin is enabled if you don't have an external reference.

Set the voltage then measure the voltage with no load, if your not seeing a voltage then you are probably not setting registers right. If you do see a voltage then put a higher load like the 150k to ground and measure the voltage, it should be the really close to the no load voltage.

\$\endgroup\$
  • \$\begingroup\$ I have used the setup reg to enable the internal reference and to set the internal reference to 2.5V I have also used the ACR reg to set both IDAC's to Range 3 I have also used the IDAC1 & IDAC2 reg to set the current on the IDAC's to 46. When I connect a multimeter up to the output of the IDAC's and try and measure mirco amps I get nothing. Thanks for the help \$\endgroup\$ – hfbroady Mar 20 '17 at 19:09
  • \$\begingroup\$ What are you setting the DAC voltage to? You need to functionally verify that the DAC is working before you set it to a low voltage\low current. \$\endgroup\$ – laptop2d Mar 20 '17 at 19:19
  • \$\begingroup\$ The DAC voltage is set with the Vrefout ( for external references only) which I have tied to ground and I'm using the internal voltage reference of 2.5V for the DAC. How do I functional test the DAC when it's internal to the chip? I have scoped all the data that I'm sending to the chip to verify it. The correct data is being sent. \$\endgroup\$ – hfbroady Mar 21 '17 at 13:24
  • \$\begingroup\$ Check the ADC or read back a register to ensure communication. Double check all power pins with the datasheet. You may want to use the internal reference for now. It might be advantageous to post a schematic. \$\endgroup\$ – laptop2d Mar 21 '17 at 15:22

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.