Tool/software:
Hi,
I am looking to use the OPA310S (with shutdown feature) in a 1.8V digital design. The datasheet lists the minimum logic high threshold for the shutdown input as V- +1.2 but I am more concerned about the max figure for this spec to ensure it does trigger at 1.8V. Is this data available? If not I would not feel comfortable using this part.
Hi Adam,
As long as the voltage at the shutdown pin is above (V-) + 1.2V, it will be a valid logic high. If you're using single supply, V- = 0V, and 1.8V > 0V + 1.2V which means that 1.8V will be interpreted as a valid logic high:
You just need to be sure that the maximum voltage at the shutdown pin does not exceed (V+) + 0.5V to avoid damaging the device.
Hi Adam,
The specifications tell you the voltages necessary to guarantee input high/low. In this case, only the minimum for VIH is relevant as it tells you the minimum voltage necessary to have the digital signal interpreted as an input high. Vice versa for VIL, as only the maximum for VIL is relevant as it tells you the maximum voltage necessary to have the digital signal interpreted as an input low.
Those minimum and maximum specifications define the red and blue regions below, which represent the voltages where the input is guaranteed as an input high and input low respectively.
