Virtex-E 1.8 V Field Programmable Gate Arrays
R
Module 2 of 4
DS022-2 (v3.0) March 21, 2014
46
Production Product Specification
— OBSOLETE — OBSOLETE — OBSOLETE — OBSOLETE —
LVDS
Depending on whether the device is transmitting an LVDS
signal or receiving an LVDS signal, there are two different
circuits used for LVDS termination. A sample circuit illustrat-
ing a valid termination technique for transmitting LVDS sig-
nals appears in
Figure 54. A sample circuit illustrating a
valid termination for receiving LVDS signals appears in
information on the specific termination resistor packs shown
LVPECL
Depending on whether the device is transmitting or receiv-
ing an LVPECL signal, two different circuits are used for
LVPECL termination. A sample circuit illustrating a valid ter-
mination
technique
for
transmitting
LVPECL
signals
appears in
Figure 56. A sample circuit illustrating a valid ter-
mination
for
receiving
LVPECL
signals
appears
in
information on the specific termination resistor packs shown
Figure 54: Transmitting LVDS Signal Circuit
Figure 55: Receiving LVDS Signal Circuit
Table 38: LVDS Voltage Specifications
Parameter
Min
Typ
Max
VCCO
2.375
2.5
2.625
VICM(2)
0.2
1.25
2.2
VOCM(1)
1.125
1.25
1.375
VIDIFF (1)
0.1
0.35
-
VODIFF (1)
0.25
0.35
0.45
VOH(1)
1.25
-
VOL(1)
-
1.25
Notes:
1.
Measured with a 100
Ω resistor across Q and Q.
2.
Measured with a differential input voltage =
+/ 350 mV.
x133_19_122799
Q
Z0 = 50Ω
Q
Virtex-E
FPGA
to LVDS Receiver
RDIV
140
R
S
165
R
S
165
2.5V
V
CCO = 2.5V
LVDS
Output
DATA
Transmit
1/4 of Bourns
Part Number
CAT16-LV4F12
x133_29_122799
Q
Z0 = 50Ω
LVDS_IN
Z0 = 50Ω
R
T
100
Ω
Q
DATA
Receive
from
LVDS
Driver
VIRTEX-E
FPGA
+
–
Table 39: LVPECL Voltage Specifications
Parameter
Min
Typ
Max
VCCO
3.0
3.3
3.6
VREF
--
-
VTT
--
-
VIH
1.49
-
2.72
VIL
0.86
-
2.125
VOH
1.8
-
VOL
-
1.57
Notes:
1.
For more detailed information, see Virtex-E 1.8V FPGA DC
and Switching Characteristics, Module 3, LVPECL DC Figure 56: Transmitting LVPECL Signal Circuit
Figure 57: Receiving LVPECL Signal Circuit
x133_20_122799
Q
Z0 = 50Ω LVPECL_OUT
LVPECL_OUT
Z0 = 50Ω
Q
Virtex-E
FPGA
to LVPECL Receiver
RDIV
187
R
S
100
R
S
100
3.3V
DATA
Transmit
1/4 of Bourns
Part Number
CAT16-PC4F12
x133_21_122799
Q
Z0 = 50Ω
LVPECL_IN
Z0 = 50Ω
R
T
100
Ω
Q
DATA
Receive
from
LVPECL
Driver
VIRTEX-E
FPGA
+
–