Responding to questions posed by its community, Ubisoft has confirmed that Splinter Cell: Conviction is a "true Microsoft exclusive title".
"... there are no plans to have Splinter Cell Conviction on other platforms," posted Ubisoft on its forums. "There are several reasons behind this choice. First of all, Splinter Cell games are historically linked with Microsoft platforms. The first Splinter Cell on the original Xbox was one of the first games to fully exploit the console’s technical possibilities. At that time, Microsoft really believed in the game potential and provided strong support to promote it. So, there is a “link of heart” between the franchise and the platform."
"The second reason behind this choice is purely linked to production. Having a single target platform means that we can optimize the game even further, because we only have one type of - console - hardware to support."
If you want to play Splinter Cell: Conviction then, it looks like your only options will be Xbox 360 and PC.