Dear all,
thank you very much for the very quick answers!
I'd be grateful if you could also help me understand the datasheets of the LM358 (
http://www.ti.com/lit/ds/symlink/lm358.pdf)
and of the OP07 (
http://www.ti.com/lit/ds/symlink/op-07-n.pdf).
Starting from the LM358, I understand that:
1) I can make the chip work with just 3V.
2) Assuming a 3V supply (GND=0V, Vcc = 3V), both IN+ and IB- must be in the range 0V --> 3V-1.5 = 1.5V.
This is how I interpret the value Vicr in the datasheet.
3) The output will be in the range OL=20mV to OH= Vcc -1.5 = 1.5.
Any intended output above these numbers will be cut.
[Actually, the values in the datasheet have been tested with Vcc=5V so maybe they are not valid for Vcc=3V]
Is this correct? Please correct me if I'm misinterpreting the data.
Since I plan to build some (very simple) circuit powered with batteries (for example a 3.7V Lipo), I'm not sure if these numbers would be very good.
About the LM07:
1) The minimum supply voltage is 6v (+/- 3V).
However, I'm not sure how to interpret the data to find the input voltage range (like IVR before) nor the output voltage range.
There is a value for the output swing, but I would like to know the distance from the rails, both from the -Vcc and from the +Vcc.
NEW QUESTION: Perhaps, narrowing a bit my previous question, I'm interested in an op-amp that can be used easily at low voltages (that's why I was asking rail-to-rail.) since I plan to work with a microcontroller like the atmega328.
At the same time I'd be happy if the same op-amp could be used at higher voltage-supplies just in case I come up with something cool to do at, say, 12v. But I guess an op-amp can not have all the good properties at the same time :-P
Thank you very much once again for your answers.