stm7007 STMicroelectronics, stm7007 Datasheet - Page 21

• Manufacturer Part Number: stm7007
• Description: Single-chip Hardware Accelerated Encryption Engine For Computer And Peripherals Applications
• Manufacturer: STMicroelectronics

3.1.1
Example: PCB impedance calculation
The PCB manufacturer should provide the board designer with all relevant parameters for
calculating trace impedance:
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Example calculation
Differential pair routed on top layer (1)
Trace width:
Inter-space trace distance: 7 mils
Ground plane on internal layer 2, giving 5.9 mils dielectric height (E
Trace thickness:
The calculator shown in
The PCB manufacturer double-checked with its tools and a more complex calculator, taking
into account the cross-section form of the top layer trace and the coating used. The PCB
manufacturer’s calculation gives a theoretical Z
Figure 9.
trace thickness
trace width
PCB material, giving E
distance between layer 1 and internal layer 2
coating thickness
UltraZ calculation for differential pair impedance
Figure 9
r
7 mils
40 μm = 1.6 mils.
Doc ID 022239 Rev 1
gives a theoretical Z
diff
= 100.2Ω .
diff
= 101.6Ω.
r
= 3.9)
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