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DS25CP104A - SmartPWDN circuitry and Output disable

Kawai
Guru 19785 points
Other Parts Discussed in Thread: DS25CP104A

Hi Team,

Please let me ask you about the SmartPWDN circuitry for DS25CP104A.

[Q1]
Is SmartPWDN circuitry active in pin configuration mode ?
I could only find the SmartPWDN description in the paragraph of register settings, SMBus Mode.


[Q2]
When does SmartPWDN circuitry disables the output driver ?
I believe there is no load detect function for the outputs. So, I think output would be disabled when there is no signal at the switched input. Am I correct ?

[Q3]
Our customer will use DS25CP104A as a 1:3 crosspoint switch. Customer requirement is to use in pin mode and output enable function for each output.
To configure output disable, I believe you could achieve by switching the output to the non connected input, if SmartPWDN function is enable at pin mode.

Best Regards,
Kawai

  • 0
    TI__Mastermind 43795 points

    Hi Kawai-san,

    [Q1]
    Is SmartPWDN circuitry active in pin configuration mode ?
    I could only find the SmartPWDN description in the paragraph of register settings, SMBus Mode.

    [A1]: The SmartPWDN circuitry or functionality is only available in SMBus mode.  In pin configuration mode the PWDN pin will enable or disable all four device outputs together.


    [Q2]
    When does SmartPWDN circuitry disables the output driver ?
    I believe there is no load detect function for the outputs. So, I think output would be disabled when there is no signal at the switched input. Am I correct ?

    [A2]: Smart PWDN disables an output driver when none of the four inputs are conigured to be connected to the output driver in question.  This is only available in SMBus mode.  Smart PWDN is used withthe SMBus Control Register at Address 0x03.  There is additional information in the "Register Descriptions" section fo the datasheet. 

    [Q3]
    Our customer will use DS25CP104A as a 1:3 crosspoint switch. Customer requirement is to use in pin mode and output enable function for each output.
    To configure output disable, I believe you could achieve by switching the output to the non connected input, if SmartPWDN function is enable at pin mode.

    [A3]:  In pin mode operation it is only possible to enable or disable the entire device at once using the PWDN# pin.  I would set the 4th output to connect just like the other 3 creating a 1:4 function.  Since the 4th output is not needed, just terminate it with 100 ohms at the output pins.

    Regards,

    Lee

  • 0 in reply to Lee Sledjeski
    Guru 19785 points

    Hi Lee-san,

    Thanks for the answers.

    Our customer's requirement is to enable/disable each channel independently with pin configuration. I think there is no device which could meet their requirement completely. I believe customer would need to use SMBus Mode to achieve this.

    Best Regards,
    Kawai