ICS858012 Datasheet, PDF (10/15 Pages) Integrated Circuit Systems – LOW SKEW, 1-TO-2, DIFFERENTIAL-TO-2.5V, 3.3V LVPECL FANOUT BUFFER

Integrated
Circuit
Systems, Inc.
PRELIMINARY
ICS858012
LOW SKEW, 1-TO-2, DIFFERENTIAL-TO-
2.5V, 3.3V LVPECL FANOUT BUFFER
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 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 6B can be eliminated and the
termination is shown in Figure 6C.
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
VCC=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
VC C=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
858012AK
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10
REV. A NOVEMBER 28, 2005