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# REF3012: REF3012 Minimum voltage spec (under limitted output condition)

Part Number: REF3012

I would like to use REF3012 with VIN=1.8V.
I found an answer "It is ok if it is slightly lower than 1.8V. The only time 1.8V comes into effect is if the device is sourcing its max current." in the thread 'REF3012: Minimum voltage spec'.
The error in the supply voltage is unavoidable, so I would like to know how low VIN REF3012 can work correctly. The output current is expected to be less than 1mA. At this time, how low VIN is possible? Also, is there  any document that correlates the output current and VIN?

thanks,

• Hi Kazkktn,

It is still recommended to use the REF3018 with 1.8 + 0.05 V on the input and this only applies for 0mA.

With 1mA, you need to add margin for drop out. The graph page 1 a typical dropout value for 25C. Is there any other rail you can use that is below 5.5V?

• Hi Marcoo,

I understand it is necessary to consider drop out even the output current is zero.

But let me confirm to make sure that the graph page 1 also applicable when the REF3012 is used on VIN=1.8V.
Referring to the graph, it makes me a little bit confusing that the dropout = 0V (@ load current = 0mA) seems to mean that it's available on VIN = 1.25V (+ 0.05 V margin may be needed separately) since the VOUT(typ.) of the REF3012 is 1.25V.

It would be helpful if you could point my misunderstanding out.

Anyway, I will check my circuit if another rail can be used for REF3012.

thanks,

• For 0mA the graph on the front page gives a typical value.

The worst case value of Vin at 1.25V at 0mA is the RoC value of 1.8V + 0.05V.

In situation where the Iload > 0mA, I would use the table 1 to get an estimate  of what a typical drop out will be then add some margin. If you expect to use this device at high temperatures, add more margin. I will usually 2x the 25C typical value as a typical estimate at 125C.

• Hi Marcoo,

All my obscure point has been cleared.