HD3SS3220 Dongle UFP EVM Features
3
SLLU241 – May 2016
Copyright © 2016, Texas Instruments Incorporated
HD3SS3220 UFP Dongle Evaluation Module
2
HD3SS3220 Dongle UFP EVM Features
2.1
Power
2.1.1
VBUS
The EVM operates off of the 5-V VBUS from the USB Type-C connection. The VBUS from the legacy
connection J2 is passed through to the Type-C connector. The end-user must make sure the Type-C
VBUS is not hot or Vsafe equals 0 V.
2.2
Connectors
The EVM has a USB Type-A and a USB Type-C receptacle. The Type-A receptacle can be used to
connect to a USB legacy device. A USB Type-C device can be connected to the USB Type-C receptacle
provided on the EVM. The EVM always present Rd on both CC pins via HD3SS3220.
2.3
Data Path
USB3 TX and RX signals are multiplexed through the HD3SS3220 to support both connection orientations
on the USB Type-C port. HD3SS3220 detects the orientation of the USB Type-C connection and
configures the high-speed MUX switch internal to the HD3SS3220.
USB2 D+1 and D+2, D-1 and D-2 are shorted on the Type-C connector to support both connection
orientations. The TUSB211 redriver can be enabled to improve the D+, D– signal integrity, if needed.
Refer to device data sheets for operation details of the HD3SS3220 (
) and TUSB211
(
2.4
AC Coupling Cap Placement
The EVM represents the AC coupling capacitor placement example to protect the HD3SS3220 switch from
Vcm above 2 V. It also shows an example of how the pulldown resistor should be placed to bias the Vcm
voltage in case there is another set of AC capacitors on the path.
The capacitors (C1 and C3) placed on the USB Type-A connector side (J1), protect the HD3SS3220 from
Vcm voltage exceeding 2 V presented on the USB RX path. The recommended value of the capacitors is
0.5 µF, as there would be another set of capacitors in series with the USB device connected through the
Type-C connector J2. The pulldown resistors R10, R11, R6, and R7 (100 k
Ω
) are placed with minimal stub
to bias Vcm.
The capacitors C2 and C4, C3 and C5 are placed for the same reasons as previously described. The
values of these capacitors are 0.5 µF, as there would be another set of capacitors(0.1 µF) in series with
the USB TX path of the USB device. The pulldown resistors R10 and R11 (100 k
Ω
) are placed with
minimal stub to bias Vcm. In a system where the HD3SS3220 is to be connected to a host through an
internal connection, only one set of 0.1-µF capacitors are needed on the Type-C connector side, therefore
no pulldown resistors are needed.
