Integrated
Circuit
Systems, Inc.
ICS853014
L
OW
S
KEW
, 1-
TO
-5
2.5V/3.3V D
IFFERENTIAL
-
TO
-LVPECL/ECL F
ANOUT
B
UFFER
ground level. The R3 in Figure 4B can be eliminated and the
termination is shown in
Figure 4C.
T
ERMINATION FOR
2.5V LVPECL O
UTPUT
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
2.5V
2.5V
2.5V
VCC=2.5V
R1
250
Zo = 50 Ohm
+
Zo = 50 Ohm
-
2,5V LVPECL
Driv er
R2
62.5
R4
62.5
R3
250
VCC=2.5V
Zo = 50 Ohm
+
Zo = 50 Ohm
-
2,5V LVPECL
Driv er
R1
50
R2
50
R3
18
F
IGURE
4A. 2.5V LVPECL D
RIVER
T
ERMINATION
E
XAMPLE
F
IGURE
4B. 2.5V LVPECL D
RIVER
T
ERMINATION
E
XAMPLE
2.5V
VCC=2.5V
Zo = 50 Ohm
+
Zo = 50 Ohm
-
2,5V LVPECL
Driv er
R1
50
R2
50
F
IGURE
4C. 2.5V LVPECL T
ERMINATION
E
XAMPLE
853014BG
www.icst.com/products/hiperclocks.html
9
REV. C MAY 13, 2005
ICS [ INTEGRATED CIRCUIT SYSTEMS ]
