ZHCSM72 June 2021 TUSB217A
PRODUCTION DATA
The ideal BOOST setting is dependent upon the signal chain loss characteristics of the target platform. The recommendation is to start with BOOST level 0, and then increment to BOOST level 1, and so on. Same applies to the RX sensitivity setting where it is recommended to plan for the required pads or connections to change boost settings, but to start with RX sensitivity level Low.
In order for the TUSB217A to recognize any change to the BOOST setting, the RSTN pin must be toggled. This is because the BOOST pin is latched on power up and the pin is ignored thereafter.
The TUSB217A compensates for extra attenuation in the signal path according to the configuration of the RX_SEN pin. This maximum recommended voltage for this pin is 5 V when selecting the highest RX sensitivity level.
Placement of the device is also dependent on the application goal. Table 9-4 summarizes our recommendations.
| PLATFORM GOAL | SUGGESTED TUSB217A PLACEMENT |
|---|---|
| Pass USB Near End Mask at the receptacle | Close to measurement point (connector) |
| Pass USB Far End Eye Mask at the plug | Close to USB PHY |
| Cascade multiple TUSB217As to improve device enumeration | Midway between each USB interconnect |
| BOOST and RX_SEN settings (1)for channel loss | ||
|---|---|---|
| Pre-channel cable length (Between USB PHY and TUSB217A) | BOOST | RX_SEN |
| 0-3 meter | Level 0 | Medium or High |
| 2-5 meter | Level 1 | Medium or High |
| Post-channel cable length (Between TUSB217A and inter-connect) | BOOST | RX_SEN |
| 0-2 meter | Level 0 | Medium or High |
| 1-4 meter | Level 1 | Medium or High |