Re: open drain
lesjo-66
The easiest way is to connect a "pullup" resistor to the the drain. Connect the other end to the desired "1" voltage, in your case this would be 1.8V. The required value of the resistor depends on the required speed. The minimum allowable value is determined by the current sinking capability of the output transistor. For example, if the output can sink 1mA, then the minimum allowable value would be 1.8/1E-3 = 1.8K.
Regards,
Kral