Hallo Raj,

I have read your posting again and again, but I'm unable to get any idea of what you want.
Equally whether you want to limit input current in case of overvoltage or not, 100kOhm and 100nF network at input is necessary anyway, because it gives you some low pass filtering, which is essential for this chip. Please do follow recommendations of datasheet, and if they put an RC-network at input, you should not omit it!

Input impedance of ICL7135 is extremely high. Only 10pA can flow at 25°C, but up to 250pA at 70°C (MAXIM's chip). It's not very wise to connect input of ICL7135 to something, which is also very high impedant, because input bias current would introduce some error: At 70°C 250pA input bias current along 400kOhm gives an error of 100µV, which equals about 1/2 LSB. At 25°C error is only 4µV. So, it would not matter at all, whether there are 200kOhm installed alone, or with additional 100kOhm series resistor. Series resistor cannot be responsible for zero reading error.

And I can't see, why series resistor at input of ICL7135 should introduce any voltage dividing of output voltage of the source. That's impossible, because input impedance of ICL7135 is extremely high.

Could you draw a schematic for illustrating the problem? This would be really helpful.

Bye,
Kai