How to extract minimum supply voltage from the datasheets

Question

I am relatively new to electronics and need to know

What is the minimum supply voltage (Vcc) for LM1875 and for LF347 and how do I extract it from the datasheets?

In LM1875 it is written that the supply range is 16V-60V but the graphs in the datasheet show a good activity also for 15V so is 15V OK?

For LMF347 it is written that the recommended conditions are min supply of 3.5. So I guess 5 volts should be OK?

Is it better to use NE5532 in which the supply is specified for a "wide range of 3V to 20V"?

Answer 1

is 15V OK?

No, the graphs indicate that a supply as low as +/- 8 V (aka a spread of 16 volts) is the minimum just as it says on page 1 of the data sheet.

For LMF347 it is written that the recommended conditions are min supply of 3.5

No, it says the minimum supply is +/- 3.5 volts - that's a total supply spread of 7 volts.

So I guess 5 volts should be OK?

+/- 5 volts would be fine but not a single supply of 5 volts.

Is it better to use NE5532 in which the supply is specified for a "wide range of 3V to 20V"?

No, the supply is specified as +/- 3 volts minimum i.e. a supply spread of 6 volts. Whether this device is better (or more suitable) depends entirely on what your circuit is intended to achieve performance wise.

Answer 2

Various output circuits, from differing technologies (bipolar, biCMOS, MOS) and differing human designers with different past experiences, will have differing output voltage ability. But there is a common factor.

^{simulate this circuit – Schematic created using CircuitLab}