I'm designing a peripheral circuit between a sensor (U1) and a MCU (U2). U1 has an open-drain output pin to indicate its status. This pin will be staying at either HIGH or LOW constantly (not frequently toggling). U2 requires 3.3V as input.
I only have 5V supply and therefore a voltage divider is used to produce 3.3V. Since the voltage divider already has high enough resistors (100k and 200k), the current flows through R1 will be really low.
In this case, do I still need a pull up (R3) for the 3.3V? In other word, can I replace R3 with a wire/jumper?