XP2 Datasheet, PDF (55/92 Pages) Lattice Semiconductor – LatticeXP2 Family Data Sheet

Lattice Semiconductor
DC and Switching Characteristics
LatticeXP2 Family Data Sheet
LVPECL
The LatticeXP2 devices support the differential LVPECL standard. This standard is emulated using complementary
LVCMOS outputs in conjunction with a parallel resistor across the driver outputs. The LVPECL input standard is
supported by the LVDS differential input buffer. The scheme shown in Figure 3-3 is one possible solution for point-
to-point signals.
Figure 3-3. Differential LVPECL
V_CCIO = 3.3V
(+/-5%)
16mA
R_S = 93.1 ohms
(+/-1%)
V_CCIO = 3.3V
(+/-5%)
16mA
R_S = 93.1 ohms
(+/-1%)
On-chip
Off-chip
R_P = 196 ohms
(+/-1%)
R_T = 100 ohms
(+/-1%)
Transmission line,
Zo = 100 ohm differential
Off-chip
+
-
On-chip
Table 3-3. LVPECL DC Conditions¹
Over Recommended Operating Conditions
Parameter
Description
V_CCIO
Output Driver Supply (+/-5%)
Z_OUT
Driver Impedance
R_S
Driver Series Resistor (+/-1%)
R_P
Driver Parallel Resistor (+/-1%)
R_T
Receiver Termination (+/-1%)
V_OH
Output High Voltage (After R₁)
V_OL
Output Low Voltage (After R₁)
V_OD
Output Differential Voltage (After R₁)
V_CM
Output Common Mode Voltage
Z_BACK
Back Impedance
I_DC
DC Output Current
1. For input buffer, see LVDS table.
Typical
3.30
10
93
196
100
2.05
1.25
0.80
1.65
100.5
12.11
Units
V
Ω
Ω
Ω
Ω
V
V
V
V
Ω
mA
3-11