Hi,
I'm trying to find an LDO linear regulator to wipe off about 2V from a 50V supply with > 60dB rejection (preferably 70dB and going out beyond 20kHz) with it being essentially flat before rolling off. Most importantly it also needs a model - for LTspice rather than Tina, though the compatibility is my problem - so that I can see it in its role on screen.
This is a precision application (at least in principle). I need it to be adjustable, though it does not have to have a 50V range and I'm quite happy to put a zener underneath it, so a 5 or 7V limit would be OK, though not probably ideal. The problem is that I cannot fish this out from the 1300 regulators with the parametric search. There is no figure for actual rejection at any frequency, nor for bandwidth. Nor, and this is much more important in this application, is there any longer a graph of output impedance on the datasheets, nor even a figure for a nominal output impedance. I would ideally like this impedance to be flat, or otherwise to have a single pole rise.
Since I can't get this from the parametric search does anyone have any experience of a TI part that might do the job? In some ways it is as simple as looking for a modern replacement for an LM317, and I do not mean a 1086 etc., but something that really does give 70dB rejection up to somewhere near 100k, before we start packing it with capacitors.
Many thanks in advance.
Christian Thomas