Specifications

S
0.96
H
diff o
Z 2Z (1 0.48(e )
æ ö
-
ç ÷
è ø
= -
o
r
60 2H T
Z ln 1.98
0.8W T
E
æ ö
+
æ ö
ç ÷
=
ç ÷
ç ÷
+
è ø
è ø
o
r
87 H
Z ln 5.98
0.8W T
E (1.41)
æ ö
æ ö
ç ÷
=
ç ÷
ç ÷
+
+
è ø
è ø
DP83848Q-Q1
www.ti.com SNLS341C –MARCH 2011–REVISED MARCH 2015
6.2.2.4 Calculating Impedance
Equation 2 through Equation 5 can be used to calculate the differential impedance of the board. For
microstrip traces, a solid ground plane is needed under the signal traces. The ground plane helps keep
the EMI localized and the trace impedance continuous. Because stripline traces are typically sandwiched
between the ground/supply planes, they have the advantage of lower EMI radiation and less noise
coupling. The trade off of using strip line is lower propagation speed.
Microstrip Impedance - Single-Ended:
(2)
Figure 6-5. Microstrip Impedance - Single-Ended
Stripline Impedance - Single-Ended:
(3)
Figure 6-6. Stripline Impedance – Single Ended
Microstrip Impedance - Differential:
(4)
Copyright © 2011–2015, Texas Instruments Incorporated Application and Implementation 67
Submit Documentation Feedback
Product Folder Links: DP83848Q-Q1