TPS22950: Can the part's ON pin be driven by 1.8V logic

Sebastian Ciesluk80

Part Number: TPS22950

Hi, I am consideringthe device to be driven by 1.8V SOC but it looks ( if I read the data sheet correctly) that there is possibility it will not work correctly .

Typical max Vol=0.2*VCC=0.2*1.8=0.36V while Tavle 7.3 in the data sheet lists Vil =0.35V max . Is it safe to connect the device to such 1V8 logic? Will it function properly. Data sheet does not state if Vil is max accepted low voltage or max voltage for internal pull up enable only?

over 1 year ago

0 Patrick Shalton over 1 year ago

TI__Mastermind 21450 points

Hi Sebastian,

Typically SOC outputs' Vols increase as they sink more current. Since the TPS22950 ON pin has very low leakage, it should be fine.

However, to cover any possibilities in case Vol is high, you can connect Vol to ON through a resistor divider - this should satisfy the Vil conditions and ensure that Vih can be ensured at 1.8V.

Also, a note - TPS22950 will be off if the ON pin is between 0-0.35V - that is the correct interpretation of Section 7.3, and there is a smart pulldown that keeps ON low after it is driven low, unless it is deliberately driven high.

Thanks,

Patrick

0 Sebastian Ciesluk80 over 1 year ago in reply to Patrick Shalton

Expert 1071 points

Thanks Patrick,

I will go this route,

Do you reckon that divider of total 100k would be high enough for the TPS22950 leakage?

0 Patrick Shalton over 1 year ago in reply to Sebastian Ciesluk80

TI__Mastermind 21450 points

Hi Sebastian,

Yes, I think 100k total would be more than strong enough given TPS22950 ON leakage is 50nA.

Thanks,

Patrick

0 Sebastian Ciesluk80 over 1 year ago in reply to Patrick Shalton

Expert 1071 points

Thanks

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TPS22950: Can the part's ON pin be driven by 1.8V logic