Timeline for If using using multiple PCA9306 for I2C voltage level translation, do I only need one resistor on the master bus?
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| Oct 1, 2023 at 11:44 | comment | added | Justme | @FridgeDetail I don't recall any more, but simply use Ohm's law. When MCU or any other chip is holding e.g. the data wire low at 0V, all resistors have one end at 0V and one end at their respective pull-up voltage, and they all pass a current that is determined by resistance and voltage, and the data pin must sink all those currents summed together. So you can't calculate a parallel resistance from resistances alone as they are different currents due to different voltage even if resistances are identical. The effective resistance isn't. | |
| Oct 1, 2023 at 11:36 | comment | added | FridgeDetail | May I ask you how you calculated the currents? I tried to think about it as three parallel resistors which would mean an effective resistance of 733 ohms. Meaning components on 3V, 3V3, and 5V would receive a current of around 4.1 mA, 4.5 mA, and 6.8 mA respectively. Did I understand correctly? | |
| Sep 15, 2023 at 6:49 | vote | accept | FridgeDetail | ||
| Sep 13, 2023 at 5:35 | history | answered | Justme | CC BY-SA 4.0 |