The 520 is SandForce[1], not Intel's own controller. It looks like Intel has given up on using their own controllers for their consumer SSDs, given that the 330 is also SandForce. Their own next generation controller is in their DC series SSDs marketed towards enterprise & datacenter usage.
[1]: http://www.anandtech.com/show/5508/intel-ssd-520-review-cher...