LVDS001EVK National Semiconductor, LVDS001EVK Datasheet - Page 4

• Manufacturer Part Number: LVDS001EVK
• Description: BOARD EVALUATION DS90LV001
• Manufacturer: National Semiconductor

Specifications of LVDS001EVK

• Main Purpose: Interface, LVDS, Repeater
• Utilized Ic / Part: DS90LV001
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Secondary Attributes: -
• Embedded: -
• Primary Attributes: -

For the microstrip line, the microstrip impedance, Z
For the new evaluation board h = 9 mils, w =15mils and t = 2.1mils. Calculating the impedance, Z
Bypassing capacitors are recommended for each package. A 0.1 µF is sufficient on the buffer device (CB1)
however, additional smaller value capacitors may be added (i.e. 0.001 µF at CB21) if desired. Traces
connecting V
to reduce inductance. Bulk bypassing is provided (C1, close by) at the main power connection as well.
Additional power supply high frequency bypassing can be added at CB2, CB12, and CB22 if desired.
Sample Waveforms from the LVDS Evaluation PCB
Single-ended signals are measured from each signal (true and inverting signals) with respect to ground. The
buffer ideally switches at the crossing point of the two signals. LVDS signals have a V
to 450mV with a typical V
use a signal between 1.0 V (V
subtracting the OUT- (inverting) signal from the OUT+ (true) signal. V
magnitude is either positive or negative, so the differential swing (V
ended waveforms and the corresponding differential waveforms are shown in Figure 5.
Figure 5: Single-ended and Differential Waveforms
Z
Z
O
O
Single-Ended Waveforms
Differential Waveform
CC
48.7 Ohms
0.475
0.475
and ground should be wide (low impedance, not 50 Ohm dimensions) and employ multiple vias
0.475
6
6
r
r
r
+ 0.67
+ 0.67
6
(4.3) + 0.67
OS
+V
of 1.2V. Our device has a typical V
±V
OD
OL
ln
ln
OD
) and 1.4 V (V
V
SS
0.67 (0.8w + t)
0.67 (0.8w + t)
ln
4h
4h
0.67 (0.8(15) + 2.1)
-V
OD
OH
4(9)
A = 1.4V V
B = 1.0V V
Ground
V
+400mV
A – B = 0V
-400mV
) for a 400 mV V
OS
Ohm
s
Ohm
s
O
= +1.2V
, is:
OH
OL
Ohm
s
t
OD
OD
of 325mV, but for the example below, we will
. The differential waveform is constructed by
SS
) is twice the V
h
W
OD
= (OUT+) – (OUT-). The V
S
r
W
OD
OD
magnitude. Drawn single-
specification of 250mV
O
, is:
OD
4