AN3357 Datasheet, PDF (8/10 Pages) STMicroelectronics – This Application note presents the HSP061-8M16 and its capability

Layout considerations
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Layout considerations
AN3357
PCB layout must be optimized to take advantage of all performances of the HSP061-8M16.
For ESD protection efficiency, the HSP061-8M16 must be located as close as possible to
the connector. This will avoid disturbance propagation to other components through the
coupling effect.
To avoid the inductance effect of PCB tracks, it is required to go directly from the connector
to the HSP061-8M16 and then after to go to the HDMI circuit. Vias to connect the ground
pins of HSP061-8M16 to the ground plane must be as many as possible and placed as
close as possible to the protection device to reduce parasitic inductance on the ground
return path. Vias to connect ground plane and the connector can be located on both sides of
the connector.
To be compliant with HDMI requirements, differential pairs must be designed with 100 Ω
differential impedance from the connector to the IC. The length of each line in the same
differential pair must be equal to minimize intra pair skew. Length of lines in different
differential pair must also be as equal as far as possible to minimize inter pair skew. Track
width must be calculated depending on PCB characteristics (relative permittivity, spacing,
number of layers…)
Figure 10 shows an example of PCB layout for HSP061-8M16 with an HDMI type A SMD
connector..
Figure 10. Layout example for HSP061-8M16 with HDMI type A SMD connector
100 Ω differential pairs As short as possible
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Doc ID 018580 Rev 1