ZHCSDC7C July 2014 – June 2017 TUSB8020B
PRODUCTION DATA.
The TUSB8020B is a two-port USB 3.0 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 TUSB8020B 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 TUSB8020B, the notebook can increase the downstream port count to three.
A common application for the TUSB8020B is as a self-powered standalone USB hub product. The product is powered by an external 5-V DC power adapter. In this application using a USB cable, TUSB8020B device’s upstream port is plugged into a USB host controller. The downstream ports of the TUSB8020B are exposed to users for connecting USB hard drives, camera, flash drive, 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 |
Number of removable downstream ports | 2 |
Number of non-removable 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 = 0) |
Battery charge support for downstream port 1 | Yes |
Battery charge support for downstream port 2 | Yes |
I2C EEPROM support | No |
24-MHz clock source | Crystal |
The upstream of the TUSB8020B is connected to a USB3 type B connector. This particular example has GANGED terminal and FULLPWRMGMTZ terminal pulled low, which results in individual power support each downstream port. The VBUS signal from the USB3 type B connector is fed 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 TUSB8020B is connected to a USB3 type A connector. With BATEN1 terminal pulled up, battery charge support is enabled for port 1. If battery charge support is not needed, then the pullup resistor on BATEN1 should be uninstalled. The PWRCTL_POL is pulled-down, which results in active-high power enable (PWRCTL1 and PWRCTL2) for a USB VBUS power switch.
The downstream port 2 of the TUSB8020B is connected to a USB3 type A connector. With BATEN2 terminal pulled up, battery charge support is enabled for port 2. If battery charge support is not needed, then the pullup resistor on BATEN2 should be uninstalled.
This particular example uses the TI TPS2561 dual-channel precision adjustable current-limited power switch. For details on this power switch or other power switches available from TI, refer to www.ti.com.