Below are two options I have considered to obtain a zener reference voltage less than 5.1 V for a comparator. A 1N5232 (5.1 V) zener is used in Circuit A, and the voltage divider will have a total resistance of around 20K. A 1N5224 (2.8 V) is used in Circuit B. The temperature coefficients are +0.04%/°C and -0.08%/°C, respectively. The comparator (LM393) is being used to maintain a fixed voltage across a large capacitor. A percent or two variation in that voltage will not matter.
My principal question is whether there is an established best practice to use one approach or the other? Also, any recommendations for the total divider resistance or other values would be appreciated.
Thanks. John
My principal question is whether there is an established best practice to use one approach or the other? Also, any recommendations for the total divider resistance or other values would be appreciated.
Thanks. John