8T49N012 Datasheet, PDF (18/28 Pages) Integrated Device Technology – Fourth Generation FemtoClock NG PLL technology

8T49N012 DATA SHEET
Termination for 2.5V LVPECL Outputs
Figure 4A and Figure 4B show examples of termination for 2.5V
LVPECL driver. These terminations are equivalent to terminating 50
to V_CCO – 2V. For V_CCO = 2.5V, the V_CCO – 2V is very close to ground
level. The R3 in Figure 4B can be eliminated and the termination is
shown in Figure 4C.
VCCO = 2.5V
50
50
2.5V LVPECL Driver
2.5V
R1
R3
250
250
2.5V
+
–
R2
R4
62.5
62.5
VCCO = 2.5V
50
50
2.5V LVPECL Driver
2.5V
+
–
R1
R2
50
50
Figure 4A. 2.5V LVPECL Driver Termination Example
Figure 4C. 2.5V LVPECL Driver Termination Example
VCCO = 2.5V
50
50
2.5V LVPECL Driver
2.5V
+
–
R1
R2
50
50
R3
18
Figure 4B. 2.5V LVPECL Driver Termination Example
FEMTOCLOCK^® NG CRYSTAL-TO-3.3V, 2.5V LVPECL/LVCMOS
18
CLOCK GENERATOR
REVISION 1 08/21/14