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WEBENCH® Tools/TPS40400: Program process difference

Part Number: TPS40400

Tool/software: WEBENCH® Design Tools

                I want to use TPS40400 to replace TPS40401. About program process, do they have difference? where can i get the difference document?


  • Hi Liwei,

        I am checking on the differences. Do you currently use the TPS40401?



  • Their are no analog/power differences between the TPS40400 and TPS40401, the changes are limited to the digital PMBus functions:

    1) TPS40401 has a wider programmable Current limit range than the TPS40400.

    The TPS40400 provides only 6 bits of programmable current limit with a fixed exponent of -1 for a maximum IOUT_OC_FAULT_LIMIT / IOUT_OC_WARN_LIMIT of 31.5A.  The TPS40401 allows for 7 bits of programmable current limit for a maximum currently limit of 63.5A

    2) The TPS40401 has a different "Identifier Code" located in MFR_SPECIFIC_44 register to differentiate the TPS40400 and TPS40401 through digital discovery.

    3) The TPS40401 prevents an false triggering of VIN_UV_FAULT, which will shut-down conversion, during the execution of a STORE_DEFAULT_ALL or STORE_DEFAULT_CODE function, though it is still recommended that customers disable output conversion while executing a STORE function.

    4) The TPS40401 disables the CLK low timeout feature, which reports a CML "Other" fault if the TPS40401 is powered up but detects a CLK voltage less than 0.8V for more than 31.5ms (typ).  The TPS40400 has this PMBus fault feature enable and will reporting a STATUS_CML "Other" fault if CLK is low for more than 31.5ms after the TPS40400 receives power, even if the CLK pin has never risen above 0.8V, such as if the PMBus termination rail is powered up after the TPS40400's supply rail.

    For converting an existing design from the TPS40401 to the TPS40400, Item 1 would be the most critical to confirm that the TPS40400's more limited current limit range is compatible with the system requirements.

    Item 2 should be checked against the existing system code to update any discovery and verification routines for proper detection.

    Items 3 and 4 would need to be checked at a system level to see if they would be a problem at the system level.

  • Hi,Peter James Miller:

        Thank you very much!!

  • Hi, Gerold:

        Yes. we use TPS40401 now.

  • Hi,

       Do you still have questions or do you consider the issue resolved?