Hello E2E Experts,
Good day.
I am using DAC7750IPWPR for 4-20mA output generation with respect to input data. The issue is with the SPI interface. I am able to provide the data to DAC from MCU. But I am not able to get data from DAC to MCU.
When I was probing the SDO from the DAC, I was able to see that data is coming from DAC, but the voltage level is very low and hence receiver is not able to detect logic high.
DVDD_EN is floating and DVDD is supplied from the on-chip regulator itself and it is 4.6V as per the datasheet. This DAC is connected to MCU through ADUM162 Isolator. This isolator one side supply is also provided from the same DVDD on-chip regulator. I have confirmed that current consumption is around 4-5mA which is less than the capability of 10mA from DVDD of DAC7750. One more thing is I am able to give the data to DAC and the current is changing as we desired (with respect to data). But the MISO (SDO) data voltage level is 2.9- 3.0 V. As per the datasheet, it should be 4.6-0.5= 4.1V. Then we read the status register and confirmed that it is proper. But I could not understand why the voltage level of SDO is lower than desired value and hence isolator(receiver) is not able to detect Logic High.
Thank you in advance for supporting us.
Regards,
CSC
