ZHCSGM0 August 2017 TUSB8042
PRODUCTION DATA.
NOTE
Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality.
The TUSB8042 is a four-port USB 3.1 Gen1 compliant hub. It provides simultaneous SuperSpeed USB and high-speed/full-speed connections on the upstream port and provides SuperSpeed USB, high-speed, full-speed, or low speed connections on the downstream port. The TUSB8042 can be used in any application that needs additional USB compliant ports. For example, a specific notebook may only have two downstream USB ports. By using the TUSB8042, the notebook can increase the downstream port count to five.
A common application for the TUSB8042 is as a self powered standalone USB hub product. The product is powered by an external 5V DC Power adapter. In this application, using a USB cable TUSB8042 upstream port is plugged into a USB Host controller. The downstream ports of the TUSB8042 are exposed to users for connecting USB hard drives, cameras, flash drives, and so forth.
DESIGN PARAMETER | EXAMPLE VALUE |
---|---|
VDD Supply | 1.1 V |
VDD33 Supply | 3.3 V |
Upstream Port USB Support (SS, HS, FS) | SS, HS, FS |
Downstream Port 1 USB Support (SS, HS, FS, LS) | SS, HS, FS, LS |
Downstream Port 2 USB Support (SS, HS, FS, LS) | SS, HS, FS, LS |
Downstream Port 3 USB Support (SS, HS, FS, LS) | SS, HS, FS, LS |
Downstream Port 4 USB Support (SS, HS, FS, LS) | SS, HS, FS, LS |
Number of Removable external exposed Downstream Ports | 4 |
Number of Non-Removable external exposed Downstream Ports | 0 |
Full Power Management of Downstream Ports | Yes. (FULLPWRMGMTZ = 0) |
Individual Control of Downstream Port Power Switch | Yes. (GANGED = 0) |
Power Switch Enable Polarity | Active High. (PWRCTL_POL = 1) |
Battery Charge Support for Downstream Port 1 | Yes |
Battery Charge Support for Downstream Port 2 | Yes |
Battery Charge Support for Downstream Port 3 | Yes |
Battery Charge Support for Downstream Port 4 | Yes |
I2C EEPROM Support | No |
24MHz Clock Source | Crystal |
The upstream of the TUSB8042 is connected to a USB3 Type B connector. This particular example has GANGED pin and FULLPWRMGMTZ pin pulled low which results in individual power support each downstream port. The VBUS signal from the USB3 Type B connector is feed through a voltage divider. The purpose of the voltage divider is to make sure the level meets USB_VBUS input requirements
The downstream port 1 of the TUSB8042 is connected to a USB3 Type A connector. With BATEN1 pin pulled up, Battery Charge support is enabled for Port 1. If Battery Charge support is not needed, then pull-up resistor on BATEN1 should be uninstalled.
The downstream port 2 of the TUSB8042 is connected to a USB3 Type A connector. With BATEN2 pin pulled up, Battery Charge support is enabled for Port 2. If Battery Charge support is not needed, then pull-up resistor on BATEN2 should be uninstalled. For ferrite bead used on the VBUS connection, a lower resistance is recommended due to noticeable IR drop during high current charging modes. The isolation between the Type-A connectors shield ground and signal ground pins is not required. Some applications may have better ESD/EMI performance when the grounds are shorted together.
The downstream port3 of the TUSB8042 is connected to a USB3 Type A connector. With BATEN3 pin pulled up, Battery Charge support is enabled for Port 3. If Battery Charge support is not needed, then pull-up resistor on BATEN3 should be uninstalled. For ferrite bead used on the VBUS connection, a lower resistance is recommended due to noticeable IR drop during high current charging modes. The isolation between the Type-A connectors shield ground and signal ground pins is not required. Some applications may have better ESD/EMI performance when the grounds are shorted together.
The downstream port 4 of the TUSB8042 is connected to a USB3 Type A connector. With BATEN4 pin pulled up, Battery Charge support is enabled for Port 4. If Battery Charge support is not needed, then pull-up resistor on BATEN4 should be uninstalled. For ferrite bead used on the VBUS connection, a lower resistance is recommended due to noticeable IR drop during high current charging modes. The isolation between the Type-A connectors shield ground and signal ground pins is not required. Some applications may have better ESD/EMI performance when the grounds are shorted together.
This particular example uses the Texas Instruments TPS2561 Dual Channel Precision Adjustable Current-Limited power switch. For details on this power switch or other power switches available from Texas Instruments, refer to the Texas Instruments website.
The PWRCTL_POL is left unconnected which results in active high power enable (PWRCTL1, PWRCTL2, PWRCTL3, and PWRCTL4) for a USB VBUS power switch. SMBUSz pin is also left unconnected which will select I2C mode. Both PWRCTL_POL and SMBUSz pins have internal pull-ups. The 1 µF capacitor on the GRSTN pin can only be used if the VDD11 supply is stable before the VDD33 supply. The depending on the supply ramp of the two supplies the capacitor size may have to be adjusted.