LM358N opamp variations?

[mikeinfodoc]

I was going to multi sim a LM358N, but I am uncertain what the U1A, U2A, etc stuff/syntax is all about?

I did not see U1A listed in the datasheet

http://www.ti.com/lit/ds/symlink/lm358-n.pdf

I assume it has something to do with 1 or 2 amp capability, but I am not sure what the U stands for.  I assume that means "Unity" gain, but this is just a guess.

Can someone help me understand the syntax/variations and what they mean?

[tooki]

I've never used Multisim, but I assume it follows common convention:

"U" is a component prefix for ICs in a schematic. (Like how R is the prefix for resistors, L for inductors, Q for transistors, etc. e.g. R3, L23, Q2.) So U1 means "IC 1".

The A/B suffix means the specific functional block within a chip that has more than one. The LM358 is a dual op-amp. So U1A means the first op-amp, and U1B means the second op-amp, within the same chip.

None of this is specific to the LM358, which is why it's not on the datasheet.

[Audioguru]

The voltage gain of an opamp is how you connect its negative feedback. Its gain could be less than unity, unity or more than unity. An opamp can even invert a signal.
A simulation of an opamp will show nothing until you learn how to connect an opamp.

The LM358 and its sister the LM324 quad opamp are two of the worst old opamps. They are noisy, produce crossover distortion and perform poorly above 2kHz at high output levels.

[tooki]

Oh, one more thing about schematics: most ICs are drawn as blocks with just numbered pins. However, some types of chips are exceptions, and tend to be drawn as their functional blocks instead. Op-amps are arguably the most common example of this, as you saw. So adding a dual op-amp chip like your LM358, instead of adding one rectangle to your schematic, adds two amplifier functional blocks (triangles) instead.

Logic gates are the other ICs that are drawn using functional blocks instead of just the IC as a whole.

In contrast, discrete components are normally drawn using a symbol specific to the component type. The package of the component is not normally reflected in the schematic.

https://learn.sparkfun.com/tutorials/how-to-read-a-schematic has a nice overview of these for beginners.

Hope this helps!