LF441 Op Amp question

[newperson]

Hi,
I was putting together a board yesterday and came across the LF441 Op Amp. It looks like I can sub this for a TL071. Is this correct?

If so, what is the difference in the data sheets saying
BAL1 (balance) and BAL2 for pins 1 and 5 and the TL071 saying
Offset N1 and Offset N2 for pins 1 and 5?

I don't know much and I am just trying to learn the difference in these terms.

Thanks for any help,
Paul.

[JKowalski]

They do the same thing.

You can check the application notes and detailed inner schematics to verify this.

[PRR]

LF441 is a grandfather to the TL071. The TL071 is MUCH cheaper, and generally better performing.

In nearly all audio uses, the offset/balance pins are NOT connected to anything. Don't even hang an inch of wire on these pins, they will pick up trouble.

In high-precision DC amplifiers (bridge strain gauges, thermocouples) the balance/offset pins allow you to trim out miniscule DC error in an optimum way. This is a bit of a legacy thing: 1960s opamps had considerable offset error to trim out. Vacuum tube opamps sometimes had a pot and Mercury battery to trim the offset, transistors respond when you lean on the input stage currents. Adding the pins was cheap. However today if you actually need microVolt DC accuracy, you buy a laser-trimmed chip, you don't dink with a TL071's input stage currents.

There are (as always) "other uses". Sometimes a circuit designer will input other signals into the balance/offset pins. This needs a good understanding of the specific opamp, and may not work on an otherwise "equivalent" part.