ICS85211I-01 Datasheet, PDF (7/13 Pages) Integrated Circuit Systems – LOW SKEW, 1-TO-2 DIFFERENTIAL-TO-HSTL FANOUT BUFFER

Integrated
Circuit
Systems, Inc.
RECOMMENDATIONS FOR UNUSED OUTPUT PINS
OUTPUTS:
HSTL OUTPUT
All unused HSTL outputs can be left floating. We recommend
that there is no trace attached. Both sides of the differential
output pair should either be left floating or terminated.
ICS85211I-01
LOW SKEW, 1-TO-2
DIFFERENTIAL-TO-HSTL FANOUT BUFFER
CLOCK INPUT INTERFACE
The CLK /nCLK accepts differential input signals of both V
SWING
and V to meet the V and V input requirements. Figures 3A
OH
PP
CMR
to 3D show interface examples for the ICS85211I-01 clock input
driven by most common driver types. The input interfaces sug-
gested here are examples only. Please consult with the vendor
of the driver components to confirm the driver termination require-
ment. For example in Figure 3, the input termination applies for
ICS HiPerClockS HSTL drivers. If you are using an HSTL driver
from another vendor, use their termination recommendation.
1.8V
Zo = 50 Ohm
Zo = 50 Ohm
LVHSTL
ICS
HiPerClockS
LVHSTL Driver
3.3V
CLK
nCLK _HiPerClockS
Input
R1
R2
50
50
3.3V
Zo = 50 Ohm
LVPECL
Zo = 50 Ohm
3.3V
CLK
nCLK _HiPerClockS
Input
R1
R2
50
50
R3
50
FIGURE 3A. ICS85211I-01 CLK/NCLK INPUT DRIVEN BY
HIPERCLOCKS HSTL DRIVER
FIGURE 3B. ICS85211I-01 CLK/NCLK INPUT DRIVEN BY
3.3V LVPECL DRIVER (INTERFACE 1)
3.3V
Zo = 50 Ohm
LVPECL
Zo = 50 Ohm
3.3V
R3
R4
125
125
3.3V
CLK
nCLK _HiPerClockS
Input
R1
R2
84
84
3. 3V
LVPECL
R5
100-200
Zo = 50 Ohm
C1
Zo = 50 Ohm
C2
R6
100-200
3. 3V
R3
R4
125
125
3.3V
CLK
nCLK _HiPerClockS
Input
R1
R2
84
84
R5,R6 locate near the driv er pin.
FIGURE 3C. ICS85211I-01 CLK/NCLK INPUT DRIVEN BY
3.3V LVPECL DRIVER (INTERFACE 2)
FIGURE 3D. ICS85211I-01 CLK/NCLK INPUT DRIVEN BY
3.3V LVPECL DRIVER WITH AC COUPLE
85211AMI-01
www.icst.com/products/hiperclocks.html
7
REV. A NOVEMBER 1, 2005