Integrated
Circuit
Systems, Inc.
ICS874005
PCI E
XPRESS
™
J
ITTER
A
TTENUATOR
the receiver input. For a multiple LVDS outputs buffer, if only
partial outputs are used, it is recommended to terminate the
un-used outputs.
3.3V
LVDS D
RIVER
T
ERMINATION
A general LVDS interface is shown in
Figure 4.
In a 100Ω
differential transmission line environment, LVDS drivers
require a matched load termination of 100Ω across near
3.3V
LVDS_Driv er
+
R1
100
-
100 Ohm Differiential Transmission Line
F
IGURE
4. T
YPICAL
LVDS D
RIVER
T
ERMINATION
S
CHEMATIC
E
XAMPLE
Figure 5
shows an example of ICS874005 application sche-
matic. In this example, the device is operated at V
DD
=3.3V. The
decoupling capacitor should be located as close as possible
to the power pin. The input is driven by a 3.3V LVPECL driver.
VDD = 3.3V
VDDO = 3.3V
Zo = 50 Ohm
+
U1
1
2
3
4
5
6
7
8
9
10
11
12
24
23
22
21
20
19
18
17
16
15
14
13
Zo = 50 Ohm
R2
100
-
nQB2
nQA1
QA1
VDDO
QA0
nQAO
MR
BW_SEL
VDDA
F_SELA
VDD
OEA
QB2
VDDO
QB1
nQB1
QB0
nQB0
F_SELB
OEB
GND
GND
nCLK
CLK
R1
10
C3
10uF
C4
0.01u
MR
BW_SEL
F_SELA
OEA
F_SELB
OEB
Zo = 50 Ohm
+
874005_tssop24
Zo = 50 Ohm
nCLK
Zo = 50 Ohm
R3
100
-
Zo = 50 Ohm
CLK
LVPECL Driv er
R4
50
(U1:23)
R6
50
R5
50
(U1:11)
(U1:4)
C5
10uf
C6
.1uf
C7
.1uf
C8
.1uf
F
IGURE
5. ICS874005 S
CHEMATIC
E
XAMPLE
874005AG
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8
REV. A JANUARY 25, 2006
ICS [ INTEGRATED CIRCUIT SYSTEMS ]
