DC and Switching Characteristics
LatticeECP2/M Family Data Sheet
Lattice Semiconductor
BLVDS
The LatticeECP2/M devices support the BLVDS standard. This standard is emulated using complementary LVC-
MOS outputs in conjunction with a parallel external resistor across the driver outputs. BLVDS is intended for use
when multi-drop and bi-directional multi-point differential signaling is required. The scheme shown in Figure 3-2 is
one possible solution for bi-directional multi-point differential signals.
Figure 3-2. BLVDS Multi-point Output Example
Heavily loaded backplane, effective Zo ~ 45 to 90 ohms differential
2.5V
16mA
2.5V
16mA
RS =
90 ohms
RS =
90 ohms
45-90
ohms
45-90
ohms
RTL
RTR
2.5V
16mA
2.5V
16mA
RS = 90 ohms
RS = 90 ohms
RS =
90 ohms
RS =
RS =
90 ohms
RS =
90 ohms
.9.0 o.hms
+
-
+
-
-
-
2.5V
2.5V
2.5V
2.5V
16mA
16mA
16mA
16mA
Table 3-3. BLVDS DC Conditions1
Over Recommended Operating Conditions
Typical
Parameter
Description
Zo = 45Ω
2.50
Zo = 90Ω
2.50
Units
V
V
Output Driver Supply (+/- 5%)
Driver Impedance
CCIO
OUT
Z
10.00
90.00
45.00
45.00
1.38
10.00
90.00
90.00
90.00
1.48
Ω
R
R
R
Driver Series Resistor (+/- 1%)
Driver Parallel Resistor (+/- 1%)
Receiver Termination (+/- 1%)
Output High Voltage
Ω
S
Ω
TL
Ω
TR
OH
OL
OD
CM
V
V
V
V
V
Output Low Voltage
1.12
1.02
V
Output Differential Voltage
Output Common Mode Voltage
DC Output Current
0.25
0.46
V
1.25
1.25
V
I
11.24
10.20
mA
DC
1. For input buffer, see LVDS table.
3-13
LATTICE [ LATTICE SEMICONDUCTOR ]
