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TPS1H000-Q1: Is the 10K ohm series resistor between TPS1H000-q1 and MCU needed

user6181224
Prodigy 10 points
Part Number: TPS1H000-Q1

I see a 10K resistor in IO lines between MCU and TPS1H000, even on an open-drain output. Why is this resistor needed? And why does it need to be so high in value?

  • 0
    TI__Mastermind 23410 points

    Hi,

    Welcome to E2E!

    The 10-kOhm resistors on the IO lines are to help protect the MCU, specifically 5V. If the MCU is 3.3V based, we recommend a 4.7-kOhm resistor. 

  • 0
    TI__Mastermind 34905 points

    Hello,

    The TPS1H000-Q1's IOs as well as your MCU IOs have ESD and body diodes. When you have transients like ISO pulses or loss of battery/ground you can potentially have positive voltage spikes around the GND/IO pins. Without a current limiting resistor there the ESD diodes may forward bias and break down in these situations. The 4.7k for 3.3V and 10k for 5V  make sure the IOs receive the correct logic level across all factors like temperatures and tolerances.