ICS853014 Datasheet, PDF (9/17 Pages) Integrated Circuit Systems – LOW SKEW, 1-TO-5 2.5V/3.3V DIFFERENTIAL-TO-LVPECL/ECL FANOUT BUFFER

Integrated
Circuit
Systems, Inc.
ICS853014
LOW SKEW, 1-TO-5
2.5V/3.3V DIFFERENTIAL-TO-LVPECL/ECL FANOUT BUFFER
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 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 4B can be eliminated and the
termination is shown in Figure 4C.
VC C=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
VC C=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
VC C=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
853014BG
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9
REV. C MAY 13, 2005