op amp input ranges

Why use an op amp that requires output offset adjustment? If you want an old op amp, use the LM1458. It too is a jelly bean (cheap) component.

"kell"

The "input voltage range" is given as (up to) + 3.8 volts with a +5 volt supply.

........ Phil

Usually the datasheet gives an "input voltage range" specified in terms of Vcc and Vee; sometimes both a safe range (guaranteed not to blow up the chip) and a specified range (guaranteed to work as specified).

For instance, looking at the TI LT1013 datasheet (it just happened to be the first one on Google), I see absolute max input range of Vee-5V to Vcc. The specified common-mode input range may be less than the safe range; for instance, on the same datasheet I see common-mode input voltage range specified from -15V to +13.5V, with +/-15V supplies, at 25C. So that's from Vee, to 1.5V below Vcc. What they're saying is that if you get closer than two diode drops to the positive rail, you won't hurt anything but they won't guarantee proper operation - for instance, it might work okay with less than a certain amount of source impedance.

Some opamps can get close to both rails, some to the positive rail, some to the negative. It depends on the circuit topology, and there are tradeoffs. So-called "single-supply" opamps, IME, generally let you get close to the negative rail but not to the positive rail.

You need to check the *input common mode voltage*on the data sheet.

Graham

A 741 does not *require* input offset adjustment. Leave those pins open if you don't need to use them.

Graham