TUSB322I_15 Datasheet, PDF (25/37 Pages) Texas Instruments – TUSB322I USB Type-C™ Configuration Channel Logic and Port Control with VCONN

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TUSB322I
SLLSEO5 – OCTOBER 2015
8.2.2.2 Detailed Design Procedure
The TUSB322I device supports a V_DD in the range of 4.5 V to 5.5 V. In this particular case, V_DD is set to 5 V. A
100-nF capacitor is placed near V_DD. Also, a 100-µF capacitor is used to meet the USB Type-C bulk capacitance
requirement of 10 µF to 220 µF.
The TUSB322I device is placed into I²C mode by either pulling the ADDR pin high or low. In this particular case,
the ADDR pin is tied to GND which results in a I²C address of 0x47. The SDA and SCL must be pulled up to
either 1.8 V or 3.3 V. When pulled up to 3.3 V, the V_DD supply must be at least 3 V to keep from back-driving the
I²C interface.
The INT_N/OUT3 pin is used to notify the PMIC when a change in the TUSB322I I²C registers occurs. This pin is
an open drain output and requires an external pullup resistor. The pin should be pulled up to V_DD using a 200-kΩ
resistor.
The DIR pin is used to control the mux for connecting the USB3 SS signals to the appropriate pins on the USB
Type-C receptacle. In this particular case, a HD3SS3212 is used as the mux. To minimize crossing in routing the
USB3 SS signals to the USB Type C connector, the connection of CC1 and CC2 to the TUSB322I is swapped.
When swapping the CC1 and CC2 connection, the CABLE_DIR register will also be reversed (0 = CC2 and 1 =
CC1).
The Type-C port mode is determined by the state of the MODE_SELECT register. When the MODE_SELECT
register is 2'b10, the TUSB322I device is in DFP mode. The TUSB322I will exit the DFP mode if the
MODE_SELECT register is changed, I2C_SOFT_RESET is set, or EN_N pin is transitioned from high to low.
The VBUS_DET pin must be connected through a 900-kΩ resistor to V_BUS on the Type-C that is connected. This
large resistor is required to protect the TUSB322I device from large V_BUS voltage that is possible in present day
systems. This resistor along with internal pulldown keeps the voltage observed by the TUSB322I device in the
recommended range.
The USB2 specification requires the bulk capacitance on V_BUS based on UFP or DFP. When operating the
TUSB322I device in a DFP mode, a bulk capacitance of at least 120 µF is required. In this particular case, a 150-
µF capacitor was chosen.
8.2.2.3 Application Curves
Figure 11. Application Curve for DFP in I²C Mode
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