ICS874003-02 Datasheet, PDF (8/14 Pages) Integrated Device Technology – PCI EXPRESS™ JITTER ATTENUATOR

ICS874003-02
PCI EXPRESS™ JITTER ATTENUATOR
DIFFERENTIAL CLOCK INPUT INTERFACE
The CLK /nCLK accepts LVDS, LVPECL, LVHSTL, SSTL, HCSL
and other differential signals. Both V and V must meet the
SWING
OH
V and V input requirements. Figures 3A to 3D show interface
PP
CMR
examples for the HiPerClockS CLK/nCLK input driven by the most
common driver types. The input interfaces suggested here are
1.8V
Zo = 50 Ohm
Zo = 50 Ohm
LVHSTL
ICS
HiPerClockS
LVHSTL Driver
3.3V
CLK
nCLK _HiPerClockS
Input
R1
R2
50
50
examples only. Please consult with the vendor of the driver
component to confirm the driver termination requirements. For
example in Figure 3A, the input termination applies for ICS
HiPerClockS LVHSTL drivers. If you are using an LVHSTL driver
from another vendor, use their termination recommendation.
3.3V
Zo = 50 Ohm
Zo = 50 Ohm
LVPECL
3.3V
CLK
nCLK _HiPerClockS
Input
R1
R2
50
50
R3
50
FIGURE 3A. HIPERCLOCKS CLK/NCLK INPUT DRIVEN BY
ICS HIPERCLOCKS LVHSTL DRIVER
FIGURE 3B. HIPERCLOCKS CLK/NCLK INPUT DRIVEN BY
3.3V LVPECL DRIVER
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
Zo = 50 Ohm
LVDS_Driv er
R1
100
Zo = 50 Ohm
3.3V
CLK
nCLK _{Receiv er}
FIGURE 3C. HIPERCLOCKS CLK/NCLK INPUT DRIVEN BY
3.3V LVPECL DRIVER
FIGURE 3D. HIPERCLOCKS CLK/NCLK INPUT DRIVEN BY
3.3V LVDS DRIVER
RECOMMENDATIONS FOR UNUSED INPUT AND OUTPUT PINS
INPUTS:
OUTPUTS:
LVCMOS CONTROL PINS:
All control pins have internal pull-ups or pull-downs; additional
resistance is not required but can be added for additional
protection. A 1kΩ resistor can be used.
LVDS
All unused LVDS output pairs can be either left floating or
terminated with 100Ω across. If they are left floating, we
recommend that there is no trace attached.
IDT^™ / ICS^™ PCI EXPRESS™ JITTER ATTENUATOR
8
ICS874003AG-02 REV A AUGUST 29, 2006