Can anyone tell me how an IC's equivalent circuit be found? i.e. 555 timer, digital gates, vregs, vrefs etc.

The books I have show a diodes, op amps, bjt and fet's equiv circuit.

 

Don't think you'll get the actual equivalent circuit for an integrated circuit because it'd be way too complicated. The best you can probably do is some sort of block diagram for the 555, for example, here on the datasheet. The device datasheet will contain all the information you're likely to need.

 

In older circuits like the 555, if you get a copy of the first data sheet it usually will give a transistor circuit diagram. This schematic is only representative; the actual circuit is proprietary.

 

You may find the NE555 circuit diagram on the page 2.
Maybe you like to duplicated the circuit as this one.

 

Are you talking about circuit schematic (you confused me with the BJT part) or actual junction layout. Because you will rarely find the PN junction layout (even if circuit is patented) but you may get the 'actual' circuit schematic if they have a patent. Otherwise what they show you in the datasheet is macro perspective (enough to properly engineer how to interface it).

 

Can anyone tell me how an IC's equivalent circuit be found? i.e. 555 timer, digital gates, vregs, vrefs etc.

The books I have show a diodes, op amps, bjt and fet's equiv circuit.

Before the advent of IC's, or until the cost came down and they became plentiful, the only way to build a circuit was with discrete semiconductors.
IOW, if you wanted a timer or a flip-flop, Schmidt trigger, ring counter, ultra sonic oscillator, they were all done with discrete transistors.
To this end, there were a series of books published in the 60's etc, mainly by Sams Publishing and others.
One was Industrial Transistor Circuits by Allan Lytel.
I don't know if you can get any old copies of these anymore, but they most likely would give you what you are looking for?
Max.

 

I notice there are a few on Abebooks clearing house, one located in Abingdon, Oxford.
Max.