855011AG 7 REV. A JANUARY 16, 2008
ICS855011
LOW SKEW, 1-TO-2
DIFFERENTIAL-TO-2.5V/3.3V CML FANOUT BUFFER
PRELIMINARY
LVPECL CLOCK INPUT INTERFACE
The PCLK /nPCLK accepts LVPECL, CML, SSTL and other
differential signals. Both V
SWING
and V
OH
must meet the V
PP
and V
CMR
input requirements.
Figures 2A to 2F
show interface
examples for the HiPerClockS PCLK/nPCLK input driven by
the most common driver types. The input interfaces suggested
here are examples only. If the driver is from another vendor,
use their termination recommendation. Please consult with
the vendor of the driver component to confirm the driver ter-
mination requirements.
FIGURE 2A. HIPERCLOCKS PCLK/nPCLK INPUT DRIVEN
BY
AN OPEN COLLECTOR CML DRIVER
FIGURE 2B. HIPERCLOCKS PCLK/nPCLK INPUT DRIVEN
BY
A BUILT-IN PULLUP CML DRIVER
FIGURE 2C. HIPERCLOCKS PCLK/nPCLK INPUT DRIVEN
BY
A 3.3V LVPECL DRIVER
FIGURE 2F. HIPERCLOCKS PCLK/nPCLK INPUT DRIVEN
BY
A 3.3V LVDS DRIVER
PCLK/nPCLK
2.5V
Zo = 60 Ohm
SSTL
HiPerClockS
PCLK
nPCLK
R2
120
3.3V
R3
120
Zo = 60 Ohm
R1
120
R4
120
2.5V
FIGURE 2E. HIPERCLOCKS PCLK/nPCLK INPUT DRIVEN
BY
AN SSTL DRIVER
HiPerClockS
PCLK
nPCLK
PCLK/nPCLK
3.3V
R2
50
R1
50
3.3V
Zo = 50 Ohm
CML
3.3V
Zo = 50 Ohm
3.3V
HiPerClockS
PCLK
nPCLK
R2
84
R3
125
Input
Zo = 50 Ohm
R4
125
R1
84
LVPECL
3.3V
3.3V
Zo = 50 Ohm
C2
R2
1K
R5
100
Zo = 50 Ohm
3.3V
3.3V
C1
R3
1K
LVDS
R4
1K
HiPerClockS
PCLK
nPCLK
R1
1K
Zo = 50 Ohm
3.3V
PC LK /n PCL K
3.3V
R5
100 - 200
3.3V
3.3V
HiPerClockS
PCLK
nPCLK
R1
125
PCLK/nPCLK
R2
125
R3
84
C1
C2
Zo = 50 Ohm
R4
84
Zo = 50 Ohm
R6
100 - 200
3.3V LVPECL
FIGURE 2D. HIPERCLOCKS PCLK/nPCLK INPUT DRIVEN
BY
A 3.3V LVPECL DRIVER WITH AC COUPLE
3.3V
3.3V
CML Built-In Pullup
R1
100
PCLK
nPCLK
HiPerClockS
PCLK/nPCLK
Zo = 50 Ohm
Zo = 50 Ohm
