9©2016 Integrated Device Technology, Inc. Revision B, February 18, 2016
85311I Datasheet
Differential Clock Input Interface
The CLK /nCLK accepts LVDS, LVPECL, LVHSTL, SSTL, HCSL 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 CLK/nCLK input driven by the most common driver
types. The input interfaces suggested here are examples only.
Please consult with the vendor of the driver component to confirm the
driver termination requirements. For example, in Figure 2A, the input
termination applies for IDT open emitter LVHSTL drivers. If you are
using an LVHSTL driver from another vendor, use their termination
recommendation.
Figure 2A. CLK/nCLK Input Driven by an
IDT Open Emitter LVHSTL Driver
Figure 2C. CLK/nCLK Input Driven by a
3.3V LVPECL Driver
Figure 2E. CLK/nCLK Input Driven by a
3.3V HCSL Driver
Figure 2B. CLK/nCLK Input Driven by a
3.3V LVPECL Driver
Figure 2D. CLK/nCLK Input Driven by a 3.3V LVDS Driver
Figure 2F. CLK/nCLK Input Driven by a
2.5V SSTL Driver
R1
50Ω
R2
50Ω
1.8V
Zo = 50Ω
Zo = 50Ω
CLK
nCLK
3.3V
LVHSTL
IDT
LVHSTL Driver
Differential
Input
H
*R
*
L
n
L
.
.
Diff
r
nti
l
In
u
CLK
nCLK
Differential
Input
SSTL
2.5V
Zo = 60
Ω
Zo = 60
Ω
2.5V
3.3V
R1
120
Ω
R2
120
Ω
R3
120
Ω
R4
120
Ω
