ADS130E08 ADC Power Supply

[javad2040]

I selected the ADS130E08 ADC for my project that will connect to Xilinx Spartan-6 FPGA. In Datasheet that TI offered, two configuration for power supply is recommended(Uni-polar and Bipolar) that I can't realize the differences between them. what is the differences and which way is better and stable? Note: that I want to measure ac signals with +- amplitudes