Are you using the load cell close to capacity, and do you need the full 18 bits. If the answer is yes to the first, and no to the second, then you probably don't need an amplifier at all. With a 12V load cell drive, your common mode voltage is 6V, which is fine for the ADC. However, see the comment about load cell drive voltage below.You need to work through an error budget, to figure out what stability you need for your front end given the number of bits required. 18 bits is around 4ppm, if your design is not good, a degree temperature change has a significant effect, you need to carefully consider that. How stable and noisy is your 12V supply to the load cell, since the load cell output is related to drive voltage. As I said, it is common to use a ratiometric measurement, where the ADC reference is used to drive the load cell. If you can't do that, you need a load cell drive voltage that has the performance to match the bits required from the ADC. It is common practice to use another channel of the ADC to measure the load cell drive voltage, but obviously it has to be within the input voltage range of the ADC, which is 10V. It is also common to use fully differential input and output op amps to drive ADC's, they are especially designed for this sort of application, the THS4561 works at 12V. You can set the gain with precision resistors. The performance, offset voltage drift for example, is nowhere like that of the AD8628, but they are designed for use with 16 to 24 bit ADCs. Note that the AD8628 is only as good as the stability of the components you place around it.You need to more fully specify your requirements, since this determines the number of bits you actually need, and therefore the precision and stability needed for the design of the front end conditioning. I use load cells, both custom and commercial in a lot of projects, I am always careful to only get the resolution and stability I really need, since each extra bit requires more effort for it to be meaningful. I often use 24bit Sigma Delta ADC's, which generally avoids the complications of adding front end conditioning, but it still requires care to get the performance specified in the data sheets,cheers,Richard