
Spartan-3 FPGA Family: DC and Switching Characteristics
10
www.xilinx.com
DS099-3 (v1.5) December 17, 2004
Advance Product Specification
R
Figure 2:
Differential Output Voltages
DS099-3_02_012304
V
OUTN
V
OUTP
GND level
50%
V
OCM
V
OCM
V
OD
V
OL
V
OH
V
OUTP
Internal
Logic
V
OUTN
N
P
= Output common mode voltage =
2
V
OUTP
+ V
OUTN
V
OD
= Output differential voltage =
V
OH
= Output voltage indicating a High logic level
V
OL
= Output voltage indicating a Low logic level
V
OUTP
- V
OUTN
Differential
I/O Pair Pins
Table 11:
DC Characteristics of User I/Os Using Differential Signal Standards
Signal Standard
Device
Revision
V
OD
Typ
(mV)
V
OD
V
OCM
Typ
(V)
V
OCM
Min
(mV)
V
OH
V
OL
Min
(mV)
430
(3)
Max
(mV)
Min
(mV)
Max
(mV)
Min
(V)
Max
(V)
Max
(mV)
Min
(V)
Max
(V)
Min
(V)
Max
(V)
LDT_25
(ULVDS_25)
All
600
670
–15
15
0.495
0.600
0.715
–15
15
0.71
1.05
0.16
0.50
LVDS_25
0
100
-
600
-
-
0.80
-
1.6
-
-
0.85
1.90
0.50
1.55
Future
250
-
450
-
-
1.125
-
-
1.375
-
-
-
1.25
1.60
0.90
1.25
BLVDS_25
All
250
350
450
-
-
1.20
-
-
-
-
-
-
LVDSEXT_25
0
100
-
600
-
-
0.80
-
1.6
-
-
0.85
1.90
0.50
1.55
Future
330
-
700
-
-
1.125
-
1.375
-
-
1.29
1.73
0.77
1.21
LVPECL_25
(6)
All
-
-
-
-
-
-
-
-
-
-
1.35
1.745
0.565
1.005
RSDS_25
0
100
-
600
-
-
0.80
-
1.6
-
-
0.85
1.90
0.50
1.55
Future
100
-
400
-
-
1.1
-
1.4
-
-
1.15
1.60
0.90
1.35
Notes:
1.
2.
3.
4.
The numbers in this table are based on the conditions set forth in
Table 5
and
Table 10
.
V
,
V
, and
V
are differential measurements.
This value must be compatible with the receiver to which the FPGA’s output pair is connected.
Output voltage measurements for all differential standards are made with a termination resistor (R
T
) of 100
across the N and P pins of the differential
signal pair.
At any given time, only one differential standard may be assigned to each bank.
Each LVPECL output-pair requires three external resistors: a 70
resistor in series with each output followed by a 240
shunt resistor. These are in
addition to the external 100
termination resistor at the receiver side. See
Figure 3
.
5.
6.
Figure 3:
External Terminations for LVPECL
240
70
70
100
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