DS125RT410_15 Datasheet, PDF (49/58 Pages) Texas Instruments – Low-Power Multi-Rate Quad Channel Retimer

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DS125RT410
SNLS459A – APRIL 2013 – REVISED OCTOBER 2015
Typical Application (continued)
8.2.2 Detailed Design Procedure
To begin the design process, determine the following:
• Maximum power draw for PCB regulator selection: for this calculation, use the maximum transient power
supply current specified in the data sheet. The lock time for each channel is typically very short, so this power
calculation should not be used for the thermal simulations of the PCB.
• Maximum operational power for thermal calculations: for this calculation, use the Average Power
Consumption value in Electrical Characteristics.
• Select a reference clock frequency and routing scheme.
• Plan out channel connectivity. Be sure to note any desired polarity inversion routing in the board schematics.
• Ensure that each device has a unique SMBus address if the control bus is shared with other devices or
components.
• Use the IBIS-AMI model for simple channel simulations before PCB layout is complete.
8.2.3 Application Curves
Figure 7 shows a typical output eye diagram for the DS125RT410 operating at 12.5 Gbps with default VOD of
600 mVp-p and de-emphasis setting of –2 dB.
Figure 8 shows an example of TX de-emphasis for a DS125RT410 operating at 12.5 Gbps. In this example, the
high speed output is configured for 600-mVp-p VOD and de-emphasis is set to –4.5 dB. An 8T pattern is used to
evaluate the driver, which consists of 0xFF00.
Figure 9 shows a typical output eye diagram for the DS125RT410 operating at 10.3125 Gbps with default VOD
of 600 mVp-p and de-emphasis setting of –2 dB.
Figure 10 shows an example of TX de-emphasis for a DS125RT410 operating at 10.3125 Gbps. In this example,
the high speed output is configured for 600-mVp-p VOD and de-emphasis is set to –4.5 dB. An 8T pattern is
used to evaluate the driver, which consists of 0xFF00.
Figure 7. Typical Output Eye Diagram for the DS125RT410
Operating at 12.5 Gbps
Figure 8. Example of TX De-emphasis for a DS125RT410
Operating at 12.5 Gbps
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