Set the CH2_EQ[2:1] pins such that the TUSB1002A equalization is between 5dB and 8dB. A value closer to

5dB maybe best if Host has transmitter de-emphasis.

A similar method can be used for the upstream path (C to D). In this particular example, C to D has a trace

length of 2 inches with a 4mil trace width. This equates to approximately 1.5dB at 5GHz. The SATA/SATA

Express/PCIe device will also have channel loss. This loss can be added to the C to D channel loss. For this

example, assume a value of 5dB is acceptable to compensate for C to D channel loss as well as loss associated

with the SATA/SATA Express/PCIe device. Set the CH1_EQ[2:1] pins such that the TUSB1002A equalization is

5dB.

SATA/PCIe/

SATA Express

Host

+

-

+

-

RX2P

RX2N

GND

TX1P

TX1N

RSVD1

TX2P

TX2N

GND

RX1P

RX1N

MODE

TUSB1002A

VCC (3.3V)

VCC (3.3V)

REQ2A

REQ2B

REQ2C

REQ2D

VCC (3.3V)

VCC (3.3V)

REQ1A

REQ1B

REQ1C

REQ1D

20<Q

CRX2

CTX1

CTX2

CRX1

VCC (3.3V)

100nF

100nF

10 µF

49.9Q

49.9Q

FB1

FB2

0-Q

GPIO (S3/S3/S5 indicator)

SATA_EN

10<Q

Figure 7-6. Example SATA/PCIe/SATA Express Schematic

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TUSB1002A

SLLSF63C – MARCH 2018 – REVISED JULY 2024

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