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TPS65218D0: About PWR_EN Pull down resistor

Part Number: TPS65218D0
Other Parts Discussed in Thread: TPS65218EVM-100,

Hi,

Could you tell me about PWR_EN Pull down resistor?
EVM circuit has the PWR_EN pin connected directly to signal pin.



However, the latest data sheets have added pull-down resistor.



Which circuit is correct?
And Please tell me why the PWR_EN pin requires a pull-down resistor.

Best regards,
Yusuke

  • Yusuke-san,

    The TPS65218EVM-100 is not a real system in that it is modified to evaluate the performance of the TPS65218D0 PMIC without the processor (typically Sitara AM335x or AM437x) connected. On the EVM, the user has manual control of whether PWR_EN pin is set high or low.

    You will notice that AC_DET also has a different wiring on the EVM than the recommendation in the datasheet.

    When PWR_EN is being driven by the SoC (processor), there should be a pull-down resistor to prevent this signal from floating high during BOOT. PWR_EN will be set high by the processor after all the I/Os have been initialized properly.