• State Resolved
  • Locked Locked
  • Replies 5 replies
  • Subscribers 65 subscribers
  • Views 308 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Original question:

TPS22910AEVM-656: EVM should be active LOW, but is acting as Active High.

TPS22910AEVM-656: 2nd EVM, TPS22910A turns off at 3.5V

Leona Mei
Prodigy 150 points
Part Number: TPS22910AEVM-656
Other Parts Discussed in Thread: TPS22910A, TPS22912C

Received a 2nd EVM board TPS22910AEVM-656. Stuffed JP2 (C2), JP6 (R1 560OHM) and JP3 is set to LO (enabling the load switch); Vin = 5V. Measuring Vout, there are no voltage. 

Set Vin = 3.3V, Vout = 3.296V

Here is a manual sweep from Vin CH1 (source from power supply), and Vout CH2. Is there a different part number for TPS22910A to operate at 5V?

  • 0
    TI__Genius 15710 points

    Hi Leona,

    Is the blue trace in your scope shot VOUT? If so, that is not the expected behavior for the device. The initial turn on of the device makes sense since the device has UVLO and will wait to turn on until VIN has reached its UVLO threshold.

    Is the device damaged after seeing the behavior in the scope shot? Also, you mentioned this is the 2nd EVM. Does the first one work without issue?

    Thanks,

    Alek Kaknevicius

  • 0 in reply to Aleksandras_Kaknevicius
    Prodigy 150 points

    Hi Alek,

    Our first order of TPS22910A-EVM was acting as enable high. Component stuffing option was different per datasheet, and the unit was acting as enable high instead of enable low eventually the board became unresponsive (Vin = 5V, nEN = High/Low, Vout = 0V). We came to conclusion that it was damaged and/or defective. We had reached out directly to TI to get a EVM replacement and received this EVM.

    Our goal is to test out automatic switching power mux solution using TPS22910A/TPS22912C. with TPS22910A nEN pin (ON) pulled up to Vin1 for TPS22912C. (giving TPS2291C priority). But are having issues with TPS22910A-EVM.

     

    Leona 

  • 0 in reply to Leona Mei
    Prodigy 150 points

    RE: Is the device damaged after seeing the behavior in the scope shot? 

    I can toggle nEN pin with Vin < 3.5V, and Vout would turn on/off as expected.

    The device works up to 3.5V. Did a sweep from 3.7V back down, Vout would turn back on when Vin hits 3.4V. 

    Leona 

  • 0 in reply to Leona Mei
    TI__Genius 15710 points

    Hi Leona,

    Based on your description and clear scope shots, the device does not seem to be acting properly. What I have done is ordered a new TPS22910AEVM from the TI store to see if I notice the same behavior on my lab bench. If so, then I can see why the device might be acting this way. I should get this early next week and will update you with the results.

    Thanks,

    Alek Kaknevicius

  • 0 in reply to Aleksandras_Kaknevicius
    TI__Genius 13470 points

    Hi Leona,

    So I got the EVM and I tested out the conditions mentioned in the original question. I observed normal behavior from the EVM we received. This result leads me to believe that the EVM you have that clamps the output voltage at 3.5V is a faulty one. My recommendation would be to obtain a new EVM and retest for your application. Below are the test conditions and the waveforms obtained.

    VIN = 5V, ON = LO, Input capacitance = 1uF (JP2), Load Resistance = 560 ohm (JP6).

    Regards,

    Andy Robles