Altera Corporation
Reference Manual
2–11
May 2006
Stratix II GX EP2SGX90 Transceiver Signal Integrity Development Board
Board Components & Interfaces
IC
S
8543 (U8): Ge
n
e
r
al P
ur
po
s
e 1:4 Diffe
r
e
n
tial Fa
n
o
u
t B
u
ffe
r
The ICS8543 is a general purpose clock buffer with a 2:1 multiplexer input
and a 1:4 differential fanout. The
clk_sel
signal determines which clock
input (i.e.,
clk
or
pclk
) is used; the chosen signal is then converted to
four output clocks. See
.
Figure 2–4. ICS8543 Clock Buffer Block Diagram
IC
S
83023 (U7): Diffe
r
e
n
tial I/O to
S
i
n
gle Co
n
ve
r
te
r
fo
r
T
r
igge
r
Clock
The ICS83023 is a differential I/O to a single-ended clock buffer, which is
used for both the PCI-Express and Basic trigger clocks. See
.
Figure 2–5. ICS83023 Clock Buffer Block Diagram
D
0
1
Q
LE
clk_en
clk
nclk
pclk
npclk
clk_sel
oe
Q0
nQ0
Q1
nQ1
Q2
nQ2
Q3
nQ3
clk0
nclk0
clk1
nclk1
Q0
Q1