DS1035 Datasheet, PDF (49/106 Pages) Dallas Semiconductor – 3-in-1 High.Speed Silicon Delay Line

DC and Switching Characteristics
MachXO2 Family Data Sheet
LVDS Emulation
MachXO2 devices can support LVDS outputs via emulation (LVDS25E). The output is emulated using complemen-
tary LVCMOS outputs in conjunction with resistors across the driver outputs on all devices. The scheme shown in
Figure 3-1 is one possible solution for LVDS standard implementation. Resistor values in Figure 3-1 are industry
standard values for 1% resistors.
Figure 3-1. LVDS Using External Resistors (LVDS25E)
VCCIO = 2.5
158
8mA
VCCIO = 2.5
8mA
140
158
On-chip
Emulated
LVDS
Buffer
Off-chip
Note: All resistors are ±1%.
Zo = 100
+
100
-
Off-chip
On-chip
Table 3-1. LVDS25E DC Conditions
Parameter
Z_OUT
R_S
R_P
R_T
V_OH
V_OL
V_OD
V_CM
Z_BACK
I_DC
Over Recommended Operating Conditions
Description
Typ.
Output impedance
20
Driver series resistor
158
Driver parallel resistor
140
Receiver termination
100
Output high voltage
1.43
Output low voltage
1.07
Output differential voltage
0.35
Output common mode voltage
1.25
Back impedance
100.5
DC output current
6.03
Units
Ohms
Ohms
Ohms
Ohms
V
V
V
V
Ohms
mA
3-10