# Will MAX660 chip get fried in this case?

#### gaganaut

Joined May 27, 2010
4
I have a question about the power supply to an op amp.

My op amp requires a Vcc of +/-5V. Now fr the +5V part, I am planning to use a 78L05 voltage regulator. But I am pretty much unsure what I need to do for -5V.

I could probably use 79L05 and get -5V directly.

Or as a friend suggested, I could use a pump converter like MAX660 to invert the voltage. But I was looking thru the specs for MAX660 and noticed that it should invert the voltage fine, but the input current is of the order of a few uA. My 78L05 produces +5V at 100mA.

So my question is that will the inverting of +5V (100mA) by using a MAX660 chip fry the MAX660 chip itself?

Any help is highly appreciated.

Thanks

#### R!f@@

Joined Apr 2, 2009
9,919
no it won't
but negative regulators are easy

#### gaganaut

Joined May 27, 2010
4
no it won't
but negative regulators are easy
Thanks R!f@@. I had the same feeling and in fact after I posted here, I realized that it should not matter. But a confirmation from an expert like you really puts the nail in the coffin. And as you suggested, I will use the negative regulator to keep my stuff simpler.

#### R!f@@

Joined Apr 2, 2009
9,919
me no expert
me simple guy

#### beenthere

Joined Apr 20, 2004
15,819
But I was looking thru the specs for MAX660 and noticed that it should invert the voltage fine, but the input current is of the order of a few uA. My 78L05 produces +5V at 100mA.

So my question is that will the inverting of +5V (100mA) by using a MAX660 chip fry the MAX660 chip itself?
I read the MAX660 data sheet as giving the maximum output of 100 ma. If the load is only one op amp, the 78L05/Max660 should work fine.

The question comes from this statement -
I could probably use 79L05 and get -5V directly.
If that means you have a negative voltage source, then the 79L05 will be superior to the MAX660.