ICS853052 Datasheet, PDF (7/14 Pages) Integrated Circuit Systems – DUAL LVCMOS / LVTTL-TO-DIFFERENTIAL 2.5V, 3.3V, 5V LVPECL MULTIPLEXER

ICS853052
DUAL LVCMOS/LVTTL-TO-DIFFERENTIAL 2.5V, 3.3V, 5V LVPECL MULTIPLEXER
APPLICATION INFORMATION
PRELIMINARY
RECOMMENDATIONS FOR UNUSED INPUT PINS
INPUTS:
DX INPUTS
For applications not requiring the use of a clock input, it can
be left floating. Though not required, but for additional
protection, a 1kΩ resistor can be tied from the Dx input to
ground.
TERMINATION FOR 2.5V LVPECL OUTPUT
Figure 1A and Figure 1B show examples of termination for 2.5V
LVPECL driver. These terminations are equivalent to terminating
50Ω to V - 2V. For V = 2.5V, the V - 2V is very close to ground
CC
CC
CC
level. The R3 in Figure 1B can be eliminated and the termination
is shown in Figure 1C.
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 1A. 2.5V LVPECL DRIVER TERMINATION EXAMPLE FIGURE 1B. 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 1C. 2.5V LVPECL TERMINATION EXAMPLE
IDT^™ / ICS^™ 2.5V, 3.3V, 5V LVPECL MULTIPLEXER
7
ICS853052AG REV. B OCTOBER 24, 2007