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TPS65987D: Table 6 in the datasheet

Joshua Kim
Intellectual 590 points
Part Number: TPS65987D

Dear,

I notice something odd in the datasheet of the TPS65987D.

Is it misspelled?

Thanks,

  • 0
    TI__Mastermind 24075 points
    Hi Jeong,
    No, there is no mistake regarding VIN_3V3. VIN_3V3 is the power supply input to TPS65987D, and current flows from VIN_3V3 to LDO_3V3 to power the core. WIthout VIN_3V3 present on boot up, the device will boot in dead battery mode. In this situation an LDO will step down VBUS to 3.3V to power internal circuitry, and this VBUS LDO is only used during dead battery configuration when VIN_3V3 absent.

    The table in your post refers to the possible configurations of dead battery boot up, based on the pin strapping of SPI_MISO and ADCIN1.
  • 0 in reply to Kedar Manishankar
    Intellectual 590 points

    Dear Kedar Manishankar,

    Thanks for the answer. I notice that Table 6 is correct; either BP_WaitFor3V3_Internal or BP_WaitFor3V3External, the device starts after VIN_3V3 present.

    However, in the datasheet, both configuration BP_WaitFor3V3_(Internal/External) concern dead battery mode, where no power source except the VBUS. 

    Can it be a contradiction to wait for the external 3.3V in the dead battery state? 

    In other words, how can I get VIN_3V3 under the dead battery?

    Thanks again,

  • 0 in reply to Joshua Kim
    TI__Mastermind 24075 points
    Hi Jeong,
    Without VIN_3V3, the device will wait until a valid 3.3V source on that pin is available. This can be accomplished by sourcing an external 3.3V directly on to this pin, or as how it is accomplished on the TPS65987D EVM. In the EVM, TPS65987D is powered by SYSPWR and accepts a 5V to 20V barrel jack connector, which is the input to a buck converter that steps the voltage down to 3.3V. You can observe the SYS_PWR, P3V3 and VIN_3V3 pins on the schematic found in this link to understand how the EVM can provide VIN_3V3.
    www.ti.com/.../slvubf3a.pdf