TUSB1004 datasheet(20/53 Pages) TI

20 / 53 page

7.3 Feature Description

7.3.1 4-Level Inputs

The TUSB1004 has 4-level inputs pins that are used to control the receiver equalization gain, transmitter voltage

swing, and place TUSB1004 into different modes of operation. These 4-level inputs utilize a resistor divider to

help set the 4 valid levels and provide a wider range of control settings. There are internal pull-up and pull-down

resistors. These resistors, together with the external resistor connection combine to achieve the desired voltage

level.

Table 7-1. 4-Level Control Pin Settings

LEVEL

SETTINGS

Tie 1-kΩ 5% to GND.

Tie 20-kΩ 5% to GND.

Float (leave pin open)

Tie 1-kΩ 5% to VCC.

Note

All 4-level inputs are latched after the rising edge of EN pin. After these pins are sampled, the internal

pull-up and pull-down resistors will be isolated in order to save power.

7.3.2 USB Receiver Linear Equalization

The purpose of receiver equalization is to compensate for channel insertion loss and inter-symbol interference

in the system before the input of the TUSB1004. The receiver overcomes these losses by attenuating the low

frequency components of the signals with respect to the high frequency components. The proper gain setting

should be selected to match the channel insertion loss before the input of the TUSB1004 receivers. Two 4-level

inputs pins enable up to 16 possible equalization settings when in pin-strap mode. The TUSB1004's USB 3.2

host, hub, and device receivers (SSTX1/2) and USB 3.2 USB connector receivers (CRX1/2) each have their own

two 4-level inputs. The TUSB1004 also provides the flexibility of adjusting settings through I2C registers.

The TUSB1004's USB host, hub, and device facing port receiver (SSTX1/2) only support Fixed EQ (FEQ). The

TUSB1004 implements three different equalizer features for the USB connector facing port receivers (CRX1

and CRX2): Fixed EQ (FEQ), Fast Adaptive EQ (Fast AEQ), and Full Adaptive EQ (Full AEQ). In Fixed EQ

operation, a single setting is used for all possible devices (with and without cable) inserted into the USB

receptacle. The Fast AEQ feature will distinguish between a short channel and a long channel. A short channel

represents a low loss use case of a USB 3.2 device plugged directly into USB receptacle without a cable. A

long channel represents the high loss use case of the USB 3.2 device plugged into the receptacle through a

USB cable. In Fast AEQ mode, TUSB1004 will select between two pre-determined settings based on whether

or not channel is short or long. When TUSB1004 is configured for Full AEQ, the TUSB1004 will automatically

determine what it believes is the best equalization setting each time a USB device is inserted into the USB

receptacle. In Full AEQ mode, the TUSB1004 will attempt to determine the best settings regardless if the

channel is short, long, or somewhere in between.

Note

Adaptive EQ is only supported on CRX1 and CRX2. Adaptive EQ must only be used when CRX1 and

CRX2 is connected to a USB receptacle. If CRX1 and CRX2 is connected directly (not through a USB

receptacle) to a USB Host, USB Hub or USB Device, then adaptive EQ must be disabled. AEQ should

never be enabled in a active cable application. If daisy chaining multiple TUSB1004, AEQ should only

be enabled on the TUSB1004 that is near the USB receptacle.

TUSB1004

SLLSFL3 – APRIL 2022

www.ti.com

Submit Document Feedback

Product Folder Links: TUSB1004

TUSB1004 датащи(PDF) 20 Page - Texas Instruments

TUSB1004 датащи(HTML) 20 Page - Texas Instruments

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53

датащи скачать

ссылки URL