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TUSB216

SLLSEZ6A – FEBRUARY 2019 – REVISED DECEMBER 2019

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Copyright © 2019, Texas Instruments Incorporated

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These parameters are starting values for a low to medium loss system. Further tuning might be required based on specific host and/or

device as well as cable length and loss profile. These settings are not specific to a 2.3V-4.3V supply system could be applicable to 5V

supply system as well.

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This resistor is needed for a VBAT supply (2.3V - 4.3V) to divide the voltage down so the BOOST pin voltage does not exceed 3.6V

Table 11. Design Parameters for 2.3-V to 4.3-V VBAT Supply With Low to Medium Loss System

PARAMETER

2.3 V to 4.3V

No

Edge and DC Boost

BOOST Level

Boost Level 0:

0-Ω

0

1.8 kΩ ±1%

1

3.6 kΩ ±1%

2

Do Not Install (DNI)

3

RX Sensitivity

RX_SEN Level

Medium RX

Sensitivity Level:

22 kΩ - 40 kΩ (27 kΩ typical)

Do Not Install (DNI)

Low

Do Not Install (DNI)

Do Not Install (DNI)

Medium

12.5 kΩ

High

8.2.2 Detailed Design Procedure

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. if permissible.

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 1.

In order for the TUSB216 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.

NOTE

The TUSB216 compensates for extra attenuation in the signal path according to the

configuration of the RX_SEN pin. This pin is not 5 V tolerant and therefore when selecting

the highest RX sensitivity level, the voltage level at RX_SEN pin must be less than 3.6V.

Placement of the device is also dependent on the application goal. Table 12 summarizes our recommendations.

Table 12. Platform Placement Guideline

PLATFORM GOAL

SUGGESTED TUSB216 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 TUSB216s to improve device enumeration

Midway between each USB interconnect

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These parameters are starting values for different cable lengths. Further tuning might be required based on specific host and/or device

as well as cable length and loss profile.

Table 13. Table of Recommended Settings

Pre-channel cable length (Between USB

PHY and TUSB216)

BOOST

RX_SEN

0-3 meter

Level 0

Medium or High

2-5 meter

Level 1

Medium or High

Post-channel cable length (Between

TUSB216 and inter-connect)

BOOST

RX_SEN

0-2 meter

Level 0

Medium or High

1-4 meter

Level 1

Medium or High