LP2981 - Reverse voltage input

mekou1

Prodigy 50 points

Other Parts Discussed in Thread: LP2981, TPS727, TLV700, TPS7A49

Hi all,

Please, i need to know is the part LP2981 (LDO) is protected againt reverser voltage on input.

What's the risk if the polarisation on the input of this LDO is reversed ?

There is another part from TI that provide the same features than LP2981 ?

Thanx in advance for all you answer and suggestion

over 14 years ago

0 JCHK over 14 years ago

TI__Mastermind 44600 points

The absolute max Vin for the LP2981 is -0.3 to 16V which means that it is not designed to support a battery reversal.

Depending on the features you are interested in, we have a wide offering of LDO's in the 100mA range. If it simply a 100mA LDO, I would recommend looking at the TLV700. This is an LDO with decent performance at a value price. If you are looking for low Iq with a fast transient respone, the TPS727 might be an option.

For reverse battery protection, I have seen instances where customers simply put a diode in series with the LDO. This is common in automotive applications.

I hope this helps.

John

0 Chris Glaser over 14 years ago

TI__Guru*** 145650 points

No, the LP2981 cannot withstand a reverse voltage as this would exceed the absolute maximum rating of -0.3V on the Vin pin.

Here is an app note that shows how to add reverse polarity protection to any circuit: http://focus.ti.com/lit/an/slva139/slva139.pdf

The newly released TPS7a4501 family can withstand reverse voltage on the input: http://focus.ti.com/docs/prod/folders/print/tps7a4501.html

0 mekou1 over 14 years ago in reply to Chris Glaser

Prodigy 50 points

Thanx for your perfect responce

0 Thorsten Brandt over 13 years ago in reply to Chris Glaser

Prodigy 110 points

Please allow me a short follow-up question :

Is the new TPS7A49 reverse voltage capable ? - at least for a decent 3.3V supercap or Li-Ion-coin-cell ?

0 Victor Ceron over 13 years ago in reply to Thorsten Brandt

TI__Prodigy 570 points

Hello Thorsten,

TPS7A49 is not reverse voltage capable, although you could connect a diode in series with the regulator to add this functionality.

Victor.

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LP2981 - Reverse voltage input