IDAC no work

[LuBe_4654241]

Hi,

I am trying the IDAC with the demo board CY8CKIT-041-41XX, but no work well.

I connected the pin 3.0 to resistor 2K49, but the voltage in some cases is not correct:

With the parameters above the voltage on resistor is about 1V5, in this case is correct.

If I use these parameters with half current the voltage on resistor is 1V36, why ?

Best regards

LuBe

[Vasanth]

Hi Lube,

What are the count values you are using in each case? Also let me know the VDDA voltage of the chip.

Best Regards,
Vasanth

[LuBe_4654241]

Hi Vasanth,

the VDDA is 1V8.

The count  value is in the image posted.

Best regards

[Vasanth]

Hi Lube,

IDAC has a parameter which is called as the compliance voltage. This ensures that the current mirrors which are the building block of the IDAC is saturated, to give expected output.

So this is the range of the IDAC it is expected to work linearly. In your use case , for voltages above 1.2V IDAC will not be able to work properly. Kindly make sure that the IDAC is used within the proper output range.

Best Regards,
Vasanth

[LuBe_4654241]

Hi Vasanth,

I don't think the problem is there, because if I set the IDAC to zero, the out value is always 880mV.

Is the connection corrected ?

Best regards

[LuBe_4654241 · Accepted solution]

Hi,

the pin 3.0 was connected to other component in the board.

Problem solved

Best regards

LuBe