Voltage is indeed dropped across the input resistor if the Op-Amp is used as an inverter, as the - input is a virtual earth. I am working on something where the Op-Amp needs to be a rail-to-rail voltage follower, though. With a high impedance input, there wouldn’t be much voltage drop in normal use.
I’ve been intending to use an MCP6021, which only tolerates 0.3v beyond supply rail voltages. I’ll check out the MCP6002, it may be a better bet for me.
Through-hole BAT 54’s seem hard to find; I thought I had found a substitute with the BAT 85, but my order for 100 from CPC (UK) has been cancelled. I’ll look at the 1N5817, thanks for the tip.
If using an unfamiliar IC, I recommend downloading the Datasheet.
Usually there is a section called ‘Absolute Maximum Ratings’ which gives the limits to voltages, temperature, etc., beyond which the chip will be damaged.
Input maxima are usually given relative to the supply voltages, but not always. There may also be a limit to the differential voltage between two inputs.
Some Op Amps, like the NE5532, have internal diodes (not Schottkys) between the inputs which limit the differential input voltage to about +/- 0.7V.anyway.
Which, incidentally can easily be tested for, to see if the NE5532 is genuine, if you are under the misapprehension that any NE5532 from China might actually be genuine.