ICS844S0258-07 Datasheet, PDF (11/21 Pages) Integrated Device Technology – Output enable signal for three LVDS outputs

ICS844S0258-07 Data Sheet
FEMTOCLOCK^® CRYSTAL/LVCMOS-TO-LVDS/LVCMOS FREQUENCY SYNTHESIZER
Crystal Input Interface
The ICS844S0258-07 has been characterized with 18pF parallel
resonant crystals. The capacitor values shown in Figure 2 below
were determined using a 25MHz, 18pF parallel resonant crystal and
were chosen to minimize the ppm error.
X1
18pF Parallel Crystal
C1
22pF
XTAL_IN
C2
22pF
XTAL_OUT
Figure 2. Crystal Input Interface
LVDS Driver Termination
A general LVDS interface is shown in Figure 4. Standard termination
for LVDS type output structure requires both a 100 parallel resistor
at the receiver and a 100 differential transmission line environment.
In order to avoid any transmission line reflection issues, the 100
resistor must be placed as close to the receiver as possible. IDT
offers a full line of LVDS compliant devices with two types of output
structures: current source and voltage source. The standard
termination schematic as shown in Figure 4 can be used with either
type of output structure. If using a non-standard termination, it is
recommended to contact IDT and confirm if the output is a current
source or a voltage source type structure. In addition, since these
outputs are LVDS compatible, the input receivers amplitude and
common mode input range should be verified for compatibility with
the output.
LVDS Driver
100Ω
+
LVDS
Receiver
–
100Ω Differential Transmission Line
Figure 4. Typical LVDS Driver Termination
ICS844S0258CK-07 REVISION A DECEMBER 2, 2013
11
©2013 Integrated Device Technology, Inc.