STPC® ATLAS
Figure 6-25. IBIS Simulation for on-board SDRAM / 90MHz
(V)
MCLKx
3
MCLKI
MCLKO
2
2.0 V
833ps
ct(s) 1
rodu 0.8 V
791ps
lete P Time
- Obso 6.5.0.1. Clock topology for standard DIMM
t(s) Figure 6-26 and Figure 6-27 give the recommend-
ed clock topology and the resulting IBIS simulation
in the case of a standard DIMM with the use of a
clock buffer.
uc Figure 6-26. Recommended topology for DIMM (IBIS model)
te Prod Buffer out
Obsole Buffer out
22 Ohms
18 Ohms
3000 mils
2000 mils
MCLKI
DIMM
Track impedance= 75 Ohms
Trace thickness = 0.72 mil
Trace width = 4 to 8 mils
94/108