The short answer is you need to design the system as a transmission line system.
I don't know of any standard SDRAM devices rated at 200MHz - for those speeds you need either DDR / DDRII / some other later spec. The notes below, however, still fully apply as much at 50MHz as at 200 (except the timing budget is easier).
If you have never designed length matched / impedance controlled systems, then I suggest allowing yourself at least a month (maybe 2) to understand the implications. There are specific relationships involved between clocks, address, data and controls, and you will also have a system timing budget. DDR in particular is quite challenging in this regard, as the data strobes are mastered by both the controller and the DDR device itself (Controller owns them during write, memory device owns them during read).
If you do not understand all the things I just mentioned, I would strongly advise you to consider carefully whether you need to interface as you mentioned. If the answer is Yes, then I suggest looking at the copious resources for such things on the web and particularly at Micron
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You will also need a capture/layout tool that can length match to within 0.030 inch (if you are particularly fortunate in your choice of device, or perhaps tighter if you are using a module).
Interfacing onto SDRAM/DDR-SDRAM is a time consuming and non-trivial task, so be prepared for a large number of calculations, which although simple, can seem rather tedious.
I have put SDRAM and DDR systems down on a circuit board both in modules and as ICs, and I can assure you it is not 'simple'. Much depends on the timing budget of the SDRAM controller (in the host), and by the time you take the varables from that and the devices themselves, it can be quite a challenge to get SDRAM running at the speed you want
Cheers
PeteS