ICS85320I Datasheet, PDF (8/14 Pages) Integrated Circuit Systems – LVCMOS / LVTTL-TO-DIFFERENTIAL 2.5V / 3.3V LVPECL TRANSLATOR

Integrated
Circuit
Systems, Inc.
ICS85320I
LVCMOS / LVTTL-TO-DIFFERENTIAL
2.5V / 3.3V LVPECL TRANSLATOR
TERMINATION FOR 2.5V LVPECL OUTPUT
Figure 2A and Figure 2B show examples of termination for 2.5V
LVPECL driver. These terminations are equivalent to terminat-
ing 50Ω to V_CC - 2V. For V_CC = 2.5V, the V_CC - 2V is very close to
ground level. The R3 in Figure 2B can be eliminated and the
termination is shown in Figure 2C.
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 2A. 2.5V LVPECL DRIVER TERMINATION EXAMPLE
FIGURE 2B. 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 2C. 2.5V LVPECL TERMINATION EXAMPLE
85320AMI
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REV. A AUGUST 25, 2004