ICS843071I Datasheet, PDF (10/15 Pages) Integrated Circuit Systems – FEMTOCLOCKS™ CRYSTAL-TO- LVPECL CLOCK GENERATOR

Integrated
Circuit
Systems, Inc.
ICS843071I
FEMTOCLOCKS™ CRYSTAL-TO- LVPECL
CLOCK GENERATOR
TERMINATION FOR 2.5V LVPECL OUTPUT
Figure 4A and Figure 4B show examples of termination for
2.5V LVPECL driver. These terminations are equivalent to ter-
minating 50Ω to V_CC - 2V. For V_CC = 2.5V, the V_CC - 2V is very
close to ground level. The R3 in Figure 4B can be eliminated
and the termination is shown in Figure 4C.
VCC=2.5V
Zo = 50 Ohm
Zo = 50 Ohm
2,5V LVPECL
Driv er
2.5V
R1
R3
250
250
2.5V
+
-
R2
62.5
R4
62.5
VCC=2.5V
Zo = 50 Ohm
Zo = 50 Ohm
2,5V LVPECL
Driv er
2.5V
+
-
R1
R2
50
50
R3
18
FIGURE 4A. 2.5V LVPECL DRIVER TERMINATION EXAMPLE
FIGURE 4B. 2.5V LVPECL DRIVER TERMINATION EXAMPLE
VCC=2.5V
Zo = 50 Ohm
Zo = 50 Ohm
2,5V LVPECL
Driv er
2.5V
+
-
R1
R2
50
50
FIGURE 4C. 2.5V LVPECL TERMINATION EXAMPLE
843071AGI
www.icst.com/products/hiperclocks.html
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REV. A JANUARY 11, 2006