Hi Vaidyanathan,
If using a gain of 1 or two, you should be able to use the potentiometer method, but if you use a gain of 64 or 128 you will be outside the common mode input range of the ADS1232. This is specified on page three of the datasheet under Common-Mode Input Range. AINxP or AINxN must be somewhere between AGND +1.5V and AVDD-1.5V when measured with respect to AGND.
Just above that specification is the Full-Scale Input Voltage range, which is +/-Vref/Gain. With Vref equal to 5V the maximum voltage that can be measured with a gain of 1 is +/- 2.5V. Be careful here because +/- does not refer to a bipolar input relative to ground. In other words, you can't apply a voltage below AGND. The +/- in this case is the AINxP input relative to the AINxN input. For example, if AINxN is connected to 2.5V, then when AINxP is greater than 2.5V you will get a positive output code. If AINxP is below 2.5V you will get a negative output code.
In no way should you exceed the Absolute Maximum Ratings found on page 2 of the datasheet. If the ADS1232 is powered from 5V for AVDD, then you should be able to apply 5V to the analog inputs as long as all of the other conditions are met in that table. Remember that even at a gain of 1 you will not be able to measure a voltage greater than 2.5V if AINxN is connected to ground. (You could measure a 0 to 5V range if AINxN is connected to 2.5V and AINxP can be 0-5V using a gain of 1, but you will have to mathmatically adjust the actual result as the output code with be with respect to 2.5V.)
If you applied a voltage on the analog inputs that affect the digital, the damage is most likely due to the Absolute Maximum Ratings being exceeded. The most common problems are related to signal transients exceeding the supply voltages, or AGND/DGND being more than 0.3V apart.
Best regards,
Bob B