ICS85310I-21 Datasheet, PDF (8/15 Pages) Integrated Circuit Systems – LOW SKEW, DUAL, 1-TO-5 DIFFERENTIAL-TO-2.5V/3.3V ECL/LVPECL FANOUT BUFFER

Integrated
Circuit
Systems, Inc.
ICS85310I-21
LOW SKEW, DUAL, 1-TO-5
DIFFERENTIAL-TO-2.5V/3.3V ECL/LVPECL FANOUT BUFFER
TERMINATION FOR 2.5V LVPECL OUTPUTS
Figure 3A and Figure 3B 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 3B can be eliminated and the
termination is shown in Figure 3C.
VC CO=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 3A. 2.5V LVPECL DRIVER TERMINATION EXAMPLE
FIGURE 3B. 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 3C. 2.5V LVPECL TERMINATION EXAMPLE
85310AYI-21
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REV. D JUNE 30, 2005