RE: How does package level trim compare to other offset correction methods?

Art Kay — Wed, 29 Jan 2014 16:54:58 GMT

Ken,

The zero drift amplifiers have some advantages over e-trim. As you mentioned, zero drift amplifiers have no 1/f noise. Also the long term shift in parameters such as offset is minimized on zero drift amplifiers because of the digital self correction. Furthermore, on rail-to-rail zero drift amplifiers the vos crossover region error is minimized because of the digital correction. However, the zero drift amplifiers do have noise feed-through from the chopping or auto-zero circuit. There is also the potential for aliasing of signals. Also, the zero drift amplifiers generally have higher bias current compared to other CMOS amplifiers.

So, in short, we will continue to develop both styles of amplifiers. There are advantages and disadvantages to each method of offset correction. Even laser trim will still be used. Many bipolar technologies to not have the capability for the digital circuits required for e-trim or zero drift.

Art

RE: How does package level trim compare to other offset correction methods?

Ken Dillinger — Mon, 27 Jan 2014 14:58:09 GMT

Moving forward are amplifiers with the new eTrim method going to "replace" those amplifiers with laser trim or auto zero topologies? I see that the low frequency noise is still higher with eTrim - makes sense that it does.

-Ken