Electrical – Do I need a level shifter with an open drain output


I'm currently doing a schematic that has an IC that operates at 3.3V (HDC1000 for those curious), and the rest of my digital operates at 1.8V. I have a level shifter for the I2C lines, but there is an active low data ready pin that is an open drain output that's used as an interrupt on the MCU.

My question is, would I need a level shifter on this line as well, or since it's an output, can I just pull this line up directly to 1.8V and have it sink the current to interrupt the MCU?

Best Answer

Not directly to 1.8V, but through a pull-up resistor of about 10K.