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AFE5401 not functioning properly

Farris Bush
Prodigy 60 points

Hello,

      I'm testing the AFE5401 EVM, but I'm having several difficulties. 

The issue is that every time I power it on, it can enter into 1 of 3 different power states: 170 mA, 380 mA, or 560 mA (at 5V). I've tried a software reset with no change (I verified the software reset by writing to the register, reading the register to see that it was written, then call reset and recheck the original register, which had all bits low). When I put the hardware reset low it reduces the power draw by 170 mA from whichever state it is in. 

I don't see any register that corresponds to switching between power states, which causes me some concern for our final designs. Additionally these power states affect the reliability of all aspects of the ADC, including adding a dc offset to the DCLK, and driving all output bits high.

Any help would be appreciated.

Farris

  • 0
    TI__Intellectual 1315 points

    Hello Farris,

    Thank you for contacting us. The applications engineer responsible for the AFE5401EVM will be online soon to help you resolve this issue.  Are you able to go through the quick start section in the EVM user's guide and capture any data?

    I'm not sure if you saw this video on AFE5401EVM. 

    A little over the minute mark in the video is a tutorial on how to use the AFE5401EVM.

  • 0 in reply to Lijoy Philipose
    TI__Genius 14540 points

    Hi Farris,

    I was able to see several power states on the EVM which I believe can be explained.  However, I was not able to see the high currents as you report. (I assume, since you are monitoring current, that you are providing +5V to the EVM through JP1 and JP2 and NOT connecting the power jack at J46.)  With the EVM jumpers set as Figure 18 of the User's Guide and with no TSW1400 connected and no USB connected, I observe 174mA 90% of the power cycles and 31mA on 10% of power cycles.  These levels are explained by the random state of the STDBY pin which can be measured at TP3.  I observe this pin changing from a low state to a high state when current changes from 174mA to 31mA. With no USB connection, power to the FTDI device is not provided and the state of STDBY pin cannot be guaranteed.

    With the USB plugged,  but no GUI running, the STBY pin is held high.  When cycling the power in this state I observe two power states of the device:  22mA and 35mA. However, as explained in section 7.5.2 of the datasheet, the internal registers must be initialized to the default value after power up.  Doing this using the SW_RST bit in register 0 always yields a power state of 22mA when the STDBY pin is held high.  And setting the STDBY pin to low state, I always observe 174mA.

    You can also remove jumpers JP22, JP28, JP56, and JP20 and provide individual power supplies to the respective test points nearby in order to monitor the current consumed by the DUT only.

    Let me know if you are still unable to reproduce these results on your EVM.

    Thanks

    Christian