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TPS65218D0: Unused processing for LS1/2.

Kengo.Y
Guru 10385 points
Part Number: TPS65218D0
Other Parts Discussed in Thread: TPS65216, TPS65218,

Hi team,

I'd like to know about unused processing for 30pin(LS1) and 34pin(LS2).
Is it OK to connect to GND?
* 31pin(IN_LS1) and 32pin(IN_LS2) is GND.

Because I'm thinking of using the TPS65216 circuit as it is.

Sincerely.
Kengo.

  • 0
    TI__Genius 15725 points

    Hi Kengo,

    Thanks for reaching out! This question has been answered on previous E2Es. Here is what we recommend when using TPS65218D0 (with GPIO2 configured as output push-pull) and TPS65216:

    • Pins# 32-33: These pins corresponds to the 2nd load switch on the TPS65218 PMIC so I recommend connecting the input (pin# 32) to GND and place a 0 Ohms resistor to GND on the output pin (pin# 33). This 0Ohm resistor can be populated when using TPS65216 to connect the pins to GND and unpopulated when using TPS65218 so you can leave them floating.

    • Pins# 30-31: These pins corresponds to 1st load switch on the TPS65218 PMIC but it is different from LS2 and LS3 because there is an internal connection between IN_LS1 and GPIO2. Because this internal connection, I would recommend connecting IN_LS1 to a valid input voltage (1.8V or 3.3V) when using TPS65218 and GND when using TPS65216. For LS1 (output of load switch), you can connect a small cap when using TPS65218 and replace it with a 0Ohms resistor to GND when using TPS65216.

    Note: We have also seen customers connecting IN_LS1/LS1 just like we recommended for IN_LS2/LS2 in the first bullet (Pins#32-33) and they did not have any issues. 

    • pin# 34 can be NC/floating. It is NC on TPS65216 and GPO2 (configured as push-pull) on TPS65218D0.

    Thanks,

    Brenda

  • 0 in reply to Brenda Diaz
    Guru 10385 points

    Hi Brenda,

    Thank you for your reply.

    I understood your recommendation.

    However, What's the problem with 30pin(LS1) and 34pin(LS2) connecting to GND?

    Sincerely.
    Kengo.


  • 0 in reply to Kengo.Y
    TI__Genius 15725 points

    Hi Kengo,

    It is not recommended to connect the output of the load switches to GND. This could generate interrupt flags on the registers. Depending on the TPS65218 variant, the load switches could also be part of the power-up sequencer.

    Thanks,

    Brenda

  • 0 in reply to Brenda Diaz
    Guru 10385 points

    Hi Brenda,

    Could you tell me the effect when connected to GND?
    Of course, The input is a GND connection.

    Sincerely.
    Kengo.

  • +1 in reply to Kengo.Y
    TI__Genius 15725 points

    Hi Kengo,

    I can't guarantee the consequences of having those output pins connected to GND because we do not validate connections that are not recommended. 

    However, this device has an EVM (TPS65218EVM-100) for our customers to evaluate the PMIC features and performance. 

    Thanks,

    Brenda

  • 0 in reply to Brenda Diaz
    Guru 10385 points

    Hi Brenda,

    Thank you for your reply.
    I know you can't guarantee it.
    But I want you to tell me the problems that can occur.
    I would like to confirm what I should care about so that customers can use it at their discretion.

    Sincerely.
    Kengo.

  • +1 in reply to Kengo.Y
    TI__Genius 15725 points

    Hi Kengo,

    We don't have data available to explain what could happen with this PMIC if the customer do not follow our recommended connections. This has not been validated or verified from our end. There could be interrupts showing up on the INT registers but I can't say if there will be other electrical/performance issues as well as reliability and quality concerns. 

    Thanks,

    Brenda