ICS85211I Datasheet, PDF (6/12 Pages) Integrated Circuit Systems – LOW SKEW, 1-TO-2 DIFFERENTIAL-TO-LVHSTL FANOUT BUFFER

Integrated
Circuit
Systems, Inc.
ICS85211I
LOW SKEW, 1-TO-2
DIFFERENTIAL-TO-LVHSTL FANOUT BUFFER
CLOCK INPUT INTERFACE
The CLK /nCLK accepts differential input signals of both V
SWING
and V_OH to meet the V_PP and V_CMR input requirements. Figures 3 to
6 show interface examples for the ICS85211I clock input driven
by most common driver types. The input interfaces suggested
here are examples only. Please consult with the vendor of the
driver components to confirm the driver termination requirement.
For example in Figure 3, the input termination applies for ICS
HiPerClockS LVHSTL drivers. If you are using an LVHSTL 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 3. ICS85211I CLK/NCLK INPUT DRIVEN BY
HIPERCLOCKS LVHSTL DRIVER
FIGURE 4. ICS85211I 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
FIGURE 5. ICS85211I CLK/NCLK INPUT DRIVEN BY
3.3V LVPECL DRIVER (INTERFACE 2)
3.3V
LVPECL
R5
100-200
Zo = 50 Ohm
C1
Zo = 50 Ohm
C2
R6
100-200
3.3V
R3
125
3.3V
R4
125
CLK
nCLK _HiPerClockS
Input
R1
R2
84
84
R5,R6 locate near the driv er pin.
FIGURE 6. ICS85211I CLK/NCLK INPUT DRIVEN BY
3.3V LVPECL DRIVER WITH AC COUPLE
85211AMI
www.icst.com/products/hiperclocks.html
6
REV. B ARPIL 8, 2003