
ICS843251I-15
FEMTOCLOCKCRYSTAL-TO-3.3V, 2.5V LVPECL CLOCK GENERATOR
IDT / ICS 3.3V, 2.5V LVPECL CLOCK GENERATOR
9
ICS843S51BGI-15 REV. A NOVEMBER 2, 2012
Termination for 2.5V LVPECL Outputs
Figure 5A and Figure 5B show examples of termination for 2.5V
LVPECL driver. These terminations are equivalent to terminating
50
to V
CC – 2V. For VCC = 2.5V, the VCC – 2V is very close to
ground level. The R3 in Figure 4B can be eliminated and the
termination is shown in Figure 5C.
Figure 5A. 2.5V LVPECL Driver Termination Example
Figure 5C. 2.5V LVPECL Driver Termination Example
Figure 5B. 2.5V LVPECL Driver Termination Example
2.5V LVPECL Driver
VCC = 2.5V
2.5V
50
Ω
50
Ω
R1
250
Ω
R3
250
Ω
R2
62.5
Ω
R4
62.5
Ω
+
–
2.5V LVPECL Driver
VCC = 2.5V
2.5V
50
Ω
50
Ω
R1
50
Ω
R2
50
Ω
+
–
2.5V LVPECL Driver
VCC = 2.5V
2.5V
50
Ω
50
Ω
R1
50
Ω
R2
50
Ω
R3
18
Ω
+
–