IMX257 NVCC_ADC&REF voltage value

[王剑翰]

In the table 6 DC Operating Conditions of IMX25CEC(REV10), it saied the Min. voltage value of REF is 2.5V. But in my customer's design, sometime the value will be down to 2.48V(or 2.47V). The REF also be supplied by NVCC_ADC(3.3V) as the SPF-26325_B1.PDF. I wonder the 2.48V is ok or not for REF? Look forward to your kindly advice.

[jimmychan]

It is an external reference of touchscreen. What is it used for in your design? In our PDK, we don't use it and tie it to GND.

[王剑翰]

I checked the i.MX25 PDK Hardware Design Files, and in the SPF-26325_B1.PDF, the REF also be supplied by NVCC_ADC(3.3V), not you said: tie it to GND. My customer add a voltage-reference which supply 2.48V to REF in the reference circuit. But, as you see, the Min. voltage value of REF is 2.5V.