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TUSB1002

SLLSEU4A – MAY 2016 – REVISED MAY 2016

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Copyright © 2016, Texas Instruments Incorporated

7.3 Feature Description

7.3.1 4-Level Control Inputs

The TUSB1002 has (MODE, CFG1, CFG2, CH1_EQ1, CH1_EQ2, CH2_EQ1, and CH2_EQ2) 4-level inputs pins

that are used to control the equalization gain and the output voltage swing dynamic range. These 4-level inputs

use a resistor divider to help set the 4 valid levels and provide a wider range of control settings. There is an

internal 45 k

Ω pull-up and a 95 kΩ pull-down. These resistors, together with the external resistor connection

combine to achieve the desired voltage level.

Table 1. 4-Level Control Pin Settings

LEVEL

SETTINGS

0

Option 1: Tie 1 K

Ω 5% to GND.

Option 2: Tie directly to GND.

R

Tie 20 K

Ω 5% to GND.

F

Float (leave pin open)

1

Option 1: Tie 1 K

NOTE

In order to conserve power, the TUSB1002 disables 4-level input’s internal pull-up/pull-

down resistors after the state of 4-level pins have been sampled on rising edge of EN. A

change of state for any four level input pin is not applied to TUSB1002 until after EN pin

transitions from low to high.

7.3.2 Linear Equalization

With a linear equalizer, the TUSB1002 can electrically shorten a particular channel allowing for longer run

lengths.

Figure 16. Linear Equalizer

With a TUSB1002, the 28 in trace can be made to have similar insertion loss as the 12 inch trace.

The receiver equalization level for each channel is determined by the state of the CHx_EQ1 and CHx_EQ2 pins,

where x = 1 or 2.