I have a common inverting integrators made using opamp (capacitor in negative feedback, +input to GND). I would like to have all these integrators saturate at the same exact voltage. Adding a zener diode in parallel to the cap works, but zeners are 2% tolerance at best and temperature dependent, and i need to make it better than that.
I wonder if I can use Shunt voltage Reference as a precision zener in this kind of circuit. I only seen shunt references used in voltage divider circuits (which they are meant for) and I am unsure, if they would also work in integrators/opamp's feedback. (their current rating isn't a problem. I checked that already)
Also, does anybody know, how good/bad is typically their forward voltage tolerance? It mentioned in datasheets and I would like the . Is it usually at least approximately on par with their reverse voltage breakdown tolerance?
Some people will probably suggest using a rail-to-rail opamps and supplying them with my reference voltages, so they would saturate there. My problem is, that modern rail-to-rail opamps do also have ESD protection diodes, which are causing glitches when used as integrator or comparator. With zener/shunt_ref in feedback, I wouldn't need modern rail-to-rail opamp and could just an old one from times, where ESD diodes were not a thing. (tl072 for example). I know about opa192 being without diodes and being rail-to-rail, but it's expensive and wouldn't work as the smallest supply voltage is 4.5V while my reference/supply voltages would be 3.3V and -0.66V, which is less.
I wish that ESD diodes yes/no would be a parameter I could use for filtering opamps somewhere. I don't think it's humanly possible to look into every r-r opamp's datasheet just to see if it has diodes and if it swings close to rails enough.
I wonder if I can use Shunt voltage Reference as a precision zener in this kind of circuit. I only seen shunt references used in voltage divider circuits (which they are meant for) and I am unsure, if they would also work in integrators/opamp's feedback. (their current rating isn't a problem. I checked that already)
Also, does anybody know, how good/bad is typically their forward voltage tolerance? It mentioned in datasheets and I would like the . Is it usually at least approximately on par with their reverse voltage breakdown tolerance?
Some people will probably suggest using a rail-to-rail opamps and supplying them with my reference voltages, so they would saturate there. My problem is, that modern rail-to-rail opamps do also have ESD protection diodes, which are causing glitches when used as integrator or comparator. With zener/shunt_ref in feedback, I wouldn't need modern rail-to-rail opamp and could just an old one from times, where ESD diodes were not a thing. (tl072 for example). I know about opa192 being without diodes and being rail-to-rail, but it's expensive and wouldn't work as the smallest supply voltage is 4.5V while my reference/supply voltages would be 3.3V and -0.66V, which is less.
I wish that ESD diodes yes/no would be a parameter I could use for filtering opamps somewhere. I don't think it's humanly possible to look into every r-r opamp's datasheet just to see if it has diodes and if it swings close to rails enough.