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LP5900: Dropout Capability clarification

David Shumate
Expert 5635 points
Part Number: LP5900
Other Parts Discussed in Thread: LP3991, LP3990,

Team,

Due to shortages we are working on replacing a LP3990 and LP3991 with a LP5900.

In the datasheet we see the following statement about dropout for LP3990:

The LP5900 has a similar statement but with higher recommendation:

The strange thing is the LP5900 specified dropout is better than the LP3990 (80mV vs 120mV)

In a situation where headroom is <1V is there any reason to expect the LP5900 would actually perform worse than the LP3990?

We have our tolerance specified as 2% for the LP5900:

Any idea what kind of tolerance hit the part would take if we were closer to 0.5V for Vin-Vout?

Best,

David

  • 0
    TI__Genius 12345 points

    Hi David, 

    The LP3990 and LP3991 have worse Vout tolerance and also use a Vin=Vout+1V or Vout+2V test case : 

    Therefore, LP5900 has better performance. If we look at the Vout change plot vs Temp: 

    Although it is Vin=Vout+1V, we can observe it is way tighter, therefore, at Vin=Vout+0.5, the device should still be within the 2% range.

    Best, 

    Edgar Acosta