SATA/PCIe/

SATA Express

Host

+

-

+

-

+

-

+

-

RXP2

RXN2

TXP2

TXN2

TUSB1002A

+

-

+

-

RXP1

RXN1

TXP1

TXN1

+

-

+

-

SATA/PCIe/

SATA Express

Device

FR4 trace

of length Y

FR4 trace

of length X

Downstream

Upstream

A

B

C

D

22

TUSB1002A

SLLSF63 – MARCH 2018

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Product Folder Links: TUSB1002A

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Copyright © 2018, Texas Instruments Incorporated

8.3 Typical SATA, PCIe and SATA Express Application

Figure 20. SATA/PCIe/SATA Express Typical Application

8.3.1 Design Requirements

Table 5. Design Parameters

PARAMETER

VALUE

VCC supply (3 V to 3.6 V)

3.3 V

PCIe Support Required (Yes/No)

Yes

SATA Express Support Required (Yes/No)

Yes

SATA Support Required (Yes/No)

Yes, then ferrite beads (FB1 and FB2) and 49.9-ohm required.

No, then ferrite bead (FB1 and FB2) and 49.9-ohm not required.

TX1, TX2, RX2 A/C coupling Capacitor (176 nF to 265 nF)

220 nF ±10%

RX1 A/C coupling Capacitor (297 nF to 363 nF)

Optional. But if implemented suggest 330 nF ±10%

A to B FR4 Length (inches)

8

A to B FR4 Trace Width (mils)

4

C to D FR4 length (inches)

2

C to D FR4 Trace Width (mils)

4

DC Gain (-2, -1, 0, +1, +2)

Not configurable when MODE = "R", CFG1 = "0", and CFG2 = "0".

Will always default to 0 dB

Linear Range (900 mV, 1000 mV, or 1200 mV)

Not configurable when MODE = "R", CFG1 = "0", and CFG2 = "0".

Will always default to 1200mV

8.3.2 Detailed Design Procedure

The MODE pin = "R", CFG1 = "0", and CFG2 = "0" will place the TUSB1002A into PCIe mode. In this mode, the

TUSB1002A will have its DC gain fixed at 0dB and its linearity range fixed at 1200mV. The TUSB1002A will

perform far-end receiver termination detection and enable both upstream and downstream paths when far-end

termination is detected on both TX1 and TX2.

The AC coupling capacitor range defined for a SATA device is a lot smaller than the AC-coupling capacitor range

defined for SATA Express and PCI Express (PCIe) as indicated by Figure 21. The AC-coupling capacitor range

defined for SATA Express and PCI Express is within the same range as the AC-coupling capacitor range defined

by USB 3.1. The TUSB1002A will be able to detect PCIe and SATA Express device's receiver termination. But

the SATA 12nF (max) AC-coupling capacitor prevents TUSB1002A from detecting the SATA device receiver

and miniCard/mSATA socket. These components can be isolated from the high-speed channel when PCIe or

SATA Express is active by using an NFET as shown in Figure 22. The NFET should be enabled whenever a