ICS813001I Datasheet, PDF (13/18 Pages) Integrated Circuit Systems – DUAL VCXO W/3.3V, 2.5V LVPECL FEMTOCLOCK-TM PLL

Integrated
Circuit
Systems, Inc.
ICS813001I
DUAL VCXO W/3.3V, 2.5V LVPECL
FEMTOCLOCK™ PLL
TERMINATION FOR 2.5V LVPECL OUTPUT
Figure 6A and Figure 6B show examples of termination for
2.5V LVPECL driver. These terminations are equivalent to ter-
minating 50Ω to V_CC - 2V. For V_CCO = 2.5V, the V_CCO - 2V is very
close to ground level. The R3 in Figure 6B can be eliminated
and the termination is shown in Figure 6C.
VC C O=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
VCCO=2.5V
Zo = 50 Ohm
Zo = 50 Ohm
2,5V LVPECL
Driv er
2.5V
+
-
R1
R2
50
50
R3
18
FIGURE 6A. 2.5V LVPECL DRIVER TERMINATION EXAMPLE
FIGURE 6B. 2.5V LVPECL DRIVER TERMINATION EXAMPLE
VCCO=2.5V
Zo = 50 Ohm
Zo = 50 Ohm
2,5V LVPECL
Driv er
2.5V
+
-
R1
R2
50
50
FIGURE 6C. 2.5V LVPECL TERMINATION EXAMPLE
813001AGI
www.icst.com/products/hiperclocks.html
13
REV. A SEPTEMBER 2, 2005