OCX160 Datasheet, PDF (22/44 Pages) List of Unclassifed Manufacturers – OCX160 Crosspoint Switch

OCX160 Crosspoint Switch—Preliminary Data Sheet
3. Differential I/O Standards
The OCX160 support the two most popular differential signaling standards: Low Voltage Differential Signaling
(LVDS) and Low Voltage Positive Emitter Coupled Logic (LVPECL).
LVDS is typically used in communication systems as high speed, low noise point-to-point links. The OCX160
conforms to the ANSI/TIA/EIA-644 standard covering electrical specifications for output drivers and receiver
inputs.
LVPECL is commonly used in video switching applications or those designs requiring transmission of high-
speed clock signals.
3.1 LVDS
LVDS is a differential signaling standard. It requires that one data bit is carried through two signal lines.
As with all differential signaling standards, LVDS has an inherent noise immunity over single-ended
standards. The voltage swing between two signal lines is approximately 350mV. The use of a reference
voltage or a board termination voltage is not required. LVDS requires the use of two pins per input or
output. LVDS requires external resistor termination.
Transmitting and receiving circuits for LVDS are shown in Figures 7 and 8.
OCX
Device
2.5V
OUTP ^RS
165
Data
RDIV
Transmit
140
R_S
VDD.PAD=2.5V
LVDS Output
OUTN ₁₆₅
Z0=50Ω
to LVDS Receiver
Z0=50Ω
to LVDS Receiver
Figure 7 Transmitting LVDS Signal Circuit
Z0=50Ω
INP
from LVDS
Driver
Z0=50Ω
R_T
100
INN
OCX
Device
+
Data
–
Recieve
Figure 8 Receiving LVDS Signal Circuit
22
[Rev. 1.6] 2/20/01
I-Cube, Inc.