AN2536 Freescale Semiconductor / Motorola, AN2536 Datasheet - Page 3

• Manufacturer Part Number: AN2536
• Description: MC9328MX1 and MC9328MXL High Speed Layout Design Guidelines
• Manufacturer: Freescale Semiconductor / Motorola

Using the typical values of W = 8 mil, H = 5 mil, T = 1.4 mil,
microstrip impedance (Z) yields the results show in Figure 2 through Figure 4. The measurement unit in
Equation 3 is mils (i.e., 1 mil = 0.001 inches). Also copper (Cu) trace thickness (T) is usually measured in
ounces (i.e., 1 oz. = 1.4 mil).
MOTOROLA
Figure 3. Microstrip Trace Impedance vs. Trace Height (H)
Figure 2. Microstrip Trace Impedance vs. Trace Width (W)
Freescale Semiconductor, Inc.
For More Information On This Product,
MC9328MX1/MXL Application Note
Z
o
Z
=
o
Go to: www.freescale.com
--------------------------- -
=
4.1
------------------------ -
87
ε
+
r
1.41
87
+
1.41
•
log
•
log


---------------------------- -
0.8 8 ( )
5.98


---------------------- -
0.8W
5.98 H
×
+
×
ε
5 ( )
+
1.4
r
T
and (FR-4) = 4.1 with and solving for




⋅
≈
Ω
50Ω
This figure shows the
microstrip trace
impedance vs. trace
height (H), using the
values in Equation 3,
keeping trace width and
trace thickness constant.
This figure shows the
microstrip trace
impedance vs. trace
width (W) using values
in Equation 3, keeping
dielectric height and
trace thickness constant.
Design Consideration
Eqn. 3
Eqn. 4
3