This weeks images are of the LMC6442 dual op-amp from National Semiconductor. The devices organization makes it somewhat easy to read with the top and bottom halves dedicated to the two op-amps. Looking at the bottom half, sick
the two inputs are at the bottom center and the op-amp output pin is in the bottom right corner. The circular structures that look like BJTs near the in/out pins are not for driving, page
but for ESD protection. It looks like the main differential transistor pairs are above the input pins around the center of the chip. The left portion of the device looks to be biasing/current-source circuitry while the right side two-three gain stages. Two metal capacitors can also be seen per op-amp which are likely used for frequency compensation.
I am going to try to focus the next few weeks on more analog ICs as well as an ADC and DAC, sales
these will hopefully be easier to “read” and will give some insights into IC layout.