HOST_TXP

HOST_TXN

HOST_RXP

HOST_RXN

CH2_EQ1

CFG2

CH2_EQ2

HOST_DM

HOST_DP

R2

DNI

C10

100 nF

C11

100 nF

VCC_3P3V

C9

10 µF

TUSB1002A

24-PIN RGE

U1

1

MODE

7

RX1N

8

RX1P

9

GND

10

TX2N

11

TX2P

12

RX2P

RX2N

GND

TX1P

TX1N

RSVD1

GND

C2

C1

220 nF

C6

C4

J1

USB3_TYPEA_CONNECTER

VBUS 1

DM 2

DP 3

GND 4

SSRXN

SSRXP 6

GND 7

SSTXN 8

SSTXP 9

SHIELD0 10

SHIELD1 11

1M

C7

100 nF

C8

0.001 µF

USB_VBUS

VCC_3P3V

CONNECT TO

USB3.1 HOST

VCC_3P3V

CFG1

CH1_EQ2

CH1_EQ1

19

20

21

22

23

24

25

VCC_3P3V

2

3

4

5

6

C3

C5

C12

330 nF

C13

330 nF

R1

R16

220 k

R15

220 k

Optional

Optional

Copyright © 2018, Texas Instruments Incorporated

5

220 nF

220 nF

220 nF

220 nF

220 nF

Figure 7-2. Host Implementation Schematic

The USB3.2 Dual channel operation is used in this example. Leave the mode pin floating (unconnected) when

using this mode.

The TUSB1002A compensates for channel loss in both the upstream (D to C) and downstream direction (A to

B). This is done by configurable the CH1_EQ[2:1] and CH2_EQ[2:1] pins to the equalization setting that matches

as close possible to the channel insertion loss. In this particular example, CH1_EQ[2:1] is for path A to B which

is the channel between USB3.2 host and the TUSB1002A, and CH2_EQ[2:1] is for path C to D which is the

channel between TUSB1002A and the USB3.2 receptacle.

The TUSB1002A supports five levels of DC gain that are selected by the CFG[2:1] pins. Typically, the DC gain is

set to 0dB but may need to be adjusted to correct any one of the following conditions:

1. Input VID too high resulting in VOD being greater than USB 3.2 defined swing. For this case, use a negative

DC gain.

2. Input VID too low resulting in VOD being less than USB 3.2 defined swing. For this case, use a positive DC

gain.

3. Low frequency discontinuities in the channel resulting in DC component of the signal clipping the vertical eye

mask. For this case, use a positive DC gain.

Assume in this example that the incoming VID is at the nominal defined USB3.2 range and the channel is linear

across frequency. The CFG1 and CFG2 pins can both be left floating if these assumptions are true.

In this particular example, the channel A-B has a trace length of 8 inches with a 4mil trace width. This particular

channel has about 0.83dB per inch of insertion loss at 5GHz. This equates to approximately 6.7dB of loss for the

entire 8 inches of trace. An additional 1.5dB of loss is added due to package of the USB3.2 Host, TUSB1002A,

and the A/C coupling capacitor. This brings the entire channel loss at 5GHz to 6.7dB + 1.5dB = 8.2dB. A typical

USB 3.1 host/device has around 3dB of transmitter de-emphasis. Transmitter de-emphasis pre-compensates for

the loss of the output channel. With 3dB of de-emphasis, the total equalization required by the TUSB1002A is

in the 5.2dB (8.2dB - 3dB) range. The channel A-B for this example is connected to the RX1P/N input of the

device, therefore the CH1_EQ[2:1] pins are used to adjust the TUSB1002A RX1P/N equalization settings. Set

the CH1_EQ[2:1] pins such that the TUSB1002A equalization is between 5dB and 8dB.

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TUSB1002A

SLLSF63C – MARCH 2018 – REVISED JULY 2024

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Product Folder Links: TUSB1002A