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TPS22990 | Performance with Vbias = 2.5V, Vin = 1.2V

Antenna_Head
Genius 12840 points
Other Parts Discussed in Thread: TPS22990

Team-

Do we have any data for the TPS22990 operating with Vbias = 2.5V?  The data sheet only goes down to Vbias = 3.3V, but says that it can go down to 2.5V.

The load in question is about 6A.

Thanks, Best, Steve

  • 0
    TI__Genius 12840 points
    Also, Bbias will have some tolerance, Vbias = 2.5V+/-5%
  • 0 in reply to Antenna_Head
    TI__Genius 15780 points

    Hi Steve,

    In the past, we have not taken any data with this voltage combination (VBIAS = 2.5V, VIN = 1.2V). If there is any specific data you would like me to collect in the lab, please let me know.

    In general, here are a few data points I can give:

    1. When VBIAS = 3.3V, the typical quiescent current is 48uA. It will be lower at VBIAS = 2.5V.
    2. When VBIAS = 3.3V, the typical VBIAS shutdown current is 4.5uA. It will be lower at VBIAS = 2.5V.
    3. The VIN shutdown current and ON pin leakage current at VBIAS = 2.5V will be negligible when compared to the VBIAS shutdown current (similar to VBIAS = 3.3V).
    4. Some of the data we have collected for on-resistance at VBIAS=2.5V is below.
    On-resistance average across 30 units
    VIN VBIAS 25C 85C
    1.05V 2.5V 3.9mΩ 4.7mΩ
    1.8V 2.5V 4.1mΩ 4.9mΩ

    Let me know if you have any questions.

    Thanks,

    Alek Kaknevicius

  • 0 in reply to Aleksandras_Kaknevicius
    TI__Genius 12840 points

    Alek-

    Thanks; this is encouraging data.

    The good news is we don't care about Iq. 

    The bad news is the Vbias could be 2.5V - 5% = 2.375V, worst case.

    We're looking for a solution in the 3-4 mOhm range, so we need to know if there is much of a different when Vbias is on the low side.  I suspect it will still work fine, but I do expect maybe a little degradation.

    The load current is ~6A.  If there is another more suitable device, please advise.

    Thanks, Best, Steve

  • 0 in reply to Antenna_Head
    TI__Genius 15780 points

    Hi Steve,

    The TPS22990 is the lowest on-resistance load switch we have. Is the issue that the VBIAS min for the device is greater than 2.5V - 5%, or that the on-resistance is above 4mΩ? Also, is it 4mΩ max or typical on-resistance?

    Another potential option may be using two TPS22920 devices in parallel. Each device has a typical on-resistance of 5.8mΩ at 1.2V, so in parallel the total solution would be 2.9mΩ. These devices are smaller than the TPS22990, so total solution size may be similar.

    Thanks,

    Alek Kaknevicius

  • 0 in reply to Aleksandras_Kaknevicius
    TI__Genius 12840 points
    Alek-

    The worst case minimum value for Vbias = 2.375V. We just need to know what happens when Vbias is at this value while Vin = 1.2V, and where is the cliff as Vbias continues to lower... just so we know how much margin there is.

    4 mOhm is probably just fine. We're just operating the part a little beyond the "Recommended" values, so want to make sure we don't get bit.