RT1731
Cable ID for USB Type-C Cables
Features
General Description
The RT1731 is Electronically-Marked ID cables IC for
both passive and active full-featured USB Type-C cable
controller complies with USB type-C and Power
Delivery application, the Electronically-Marked ID
cables support USB Power Delivery Structured VDM
Discover Identity command directed to SOP’. With
Electrically-Marked Cable ID, the DFP host can
determine the characteristics of the cable, e.g. its
current carrying capability, its performance, and vendor
identification, the RT1731 features VBUS short
protection on VCONN and CCIN to avoid pin short
when VBUS voltage rises above 20V after PD
communication is complete.
The RT1731 is available in WDFN-8L 2x2 and
WL-CSP-8B 0.96x1.64 (BSC) packages.
Support I2C Bus for Programming VDM Data
Power
Support 3V to 5.5V Operation on
VCON1/VCON2 Pin
Protection
HV Protection of VCON1/VCON2/CCIN
Package
WDFN-8L 2x2
RT1731
Lead Plating System
G : Green (Halogen Free and Pb Free)
(WDFN Only)
Write Protect on Multi One-Time Programmable
(OTP) Memory
Ordering Information
Package Type
QW : WDFN-8L 2x2 (W-Type)
WSC : WL-CSP-8B 0.96x1.64 (BSC)
Type-C Support/PD Support
Support SOP’ and SOP’’ Communication
Support Host Authentication
Support Additional Modal Operation
Advantage
Embedded Both Side RA Resistor
Embedded Both Side ISO Diode
Support Multi-Time Writable Memory to Store
VDM Data
Support Custom Structured VDM Writing Over
CC Pin
WL-CSP-8B 0.96x1.64 (BSC)
Applications
Note :
USB Full-Featured Type-C Cables
Type-C Active Cable
Richtek products are :
Type-C Passive Cable
RoHS compliant and compatible with the current
requirements of IPC/JEDEC J-STD-020.
Suitable for use in SnPb or Pb-free soldering
processes.
Simplified Application Circuit
CC
VCONN1
VCONN2
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DS1731-02
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RT1731
VCON1
VCON2
CCIN
GND
NC
SCL
NC
SDA
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RT1731
Marking Information
RT1731GQW
4TW
RT1731WSC
4T : Product Code
W : Date Code
72W
72 : Product Code
W : Date Code
Pin Configuration
(TOP VIEW)
VCON1
A1
A2
VCON2
CCIN
B1
B2
SCL
NC
NC
C1
C2
SDA
NC
NC
D1
D2
GND
1
8
VCON1
GND
2
7
CCIN
SCL
3
6
SDA
4
5
NC
VCON2
9
WL-CSP-8B 0.96x1.64 (BSC)
WDFN-8L 2x2
Functional Pin Description
Pin No.
Pin Name
Pin Function
WDFN-8L 2x2
WL-CSP-8B
0.96x1.64 (BSC)
1
A2
VCON2
The power is input pin supplied from VCONN with resistor RA
termination and has high voltage protection at 22V.
2
D2
GND
Ground pin.
3
B2
SCL
This pin is only used for debug. No internal connection.
(Recommend to connect to GND)
4
C2
SDA
This pin is only used for debug. No internal connection.
(Recommend to connect to GND)
5, 6
C1, D1
NC
No internal connection. (Recommend to connect to GND)
7
B1
CCIN
The configuration channel pin used in the discovery,
configuration and management of connections, includes high
voltage protection at 22V.
8
A1
VCON1
The power is input pin supplied from VCONN with resistor RA
termination and has high voltage protection at 22V.
9
(Exposed Pad)
--
NC
No internal connection. The exposed pad must be soldered to a
large PCB and connected to GND for maximum power
dissipation.
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RT1731
Functional Block Diagram
SCL
SDA
2
M-OTP
I C Controller
Internal Bus
Cable Policy
Engine
MUX Control
Register Block
Protocol Layer
Detection
Voltage
Regulator
USB PD Physical
Layer
VCON1
CCIN
RA
RA
GND
VCON2
Operation
SOP’ and SOP’’ Communication
A Cable Plug capable of SOP’ Communication shall
only detect and communicate with packets starting with
SOP’. The eMarker in a Passive Cable shall be capable
of SOP’ Communication only after VCONN is on. Or
the eMarker in an Active Cable shall be capable of
SOP’ Communication only after VCONN is on and
SOP’’ Controller is not present.
40Gbps Model operation. There are several
SVID/MODE configuration setting to supports up to 3
kinds of Modal operation (40Gbps Modal Operation
included). Flexibility is retained for new applications in
the feature.
PD 3.0 Compliance
A Cable Plug capable of SOP’’ Communication shall
have a SOP’ Communication capability in the other
The RT1731 supports PD3.0 Get_Status capability.
Customized response above will be returned. The
RT1731 also support Active Cable VDO and Active
Cable VDO2 response when product is configured as
Cable Plug. No cable shall only support SOP’’
Communication. A Cable Plug to which SOP’’
PD3.0, Active Cable VDO version = 1.2 and act as
Active Cable.
Communication is assigned shall only detect and
communicate with packets starting with SOP’’. The
eMarker in an Active Cable with SOP’’ Controller
present will support SOP’ communication in one Cable
Plug and SOP’’ communication in the other Cable Plug.
The term Cable Plug in the SOP’ Communication and
SOP’’ Communication case is used to represent a
logical entity (RT1731) in the cable which is capable of
PD Communication.
PD Modal Operation
The RT1731 supports PD Model operation when the
feature of Mode Enter/Exit process is specified, e.g.
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Proprietary Authentication
Proprietary
Authentication
is
supported
with
cooperating Device, TA, etc., that need certain
authentication before enabling proprietary charging or
customized function to ensure Cable Plug’s reliability
and quality.
Inter-Frame Gap Timings
The transmitter (Host command) shall drive the bus for
no longer than tEndDriveBMC after transmitting the final
bit of the Frame.
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RT1731
Cable Response (GoodCRC)
Host Command
Bus driven after
end of Frame
End of Frame
Bus driven before
Preamble
Preamble
tInterFrameGap
tEndDriveBFSK or
tStartDrive
tEndDriveBMC
Figure1. Inter-Frame Gap Timings
The GoodCRC Message shall be sent by the receiver to acknowledge that the previous Message was correctly
received (i.e. had a good CRC). The GoodCRC Message shall return the Message’s MessageID so the transmitter
can determine that the correct Message is being acknowledged. The first bit of the GoodCRC Message shall be
returned within tTransmit after receipt of the last bit of the previous Message.
BMC Encoded Start of Preamble
The transmitter may vary the start of the Preamble by tStartDrive min. When sending the Preamble, the transmitter
shall start by transmitting a low level. The receiver shall tolerate the loss of the first edge.
0
1
0
1
1UI
1UI
1UI
0
etc
1
High Impedance
(level set by Rp/Rd)
1UI
1UI
1UI
tStartDrive
Figure 2. BMC Encoded Start of Preamble
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RT1731
Transmitting or Receiving BMC Encoded Frame Terminated
The end of a BMC encoded Frame with an encoded zero for which the final bit of the Frame is terminated by a high
to low transition.
Final bit
of frame
0
Preamble for
next frame
Trailing edge
of final bit
0
High Impedance
(level set by Rp/Rd)
1UI
min tHoldLowBMC
max tEndDriveBMC
tInterFrameGap
Figure 3. tInterFrameGap
Biphase Mark Coding (BMC) Signaling Scheme
Biphase Mark Coding is the physical layer Signaling Scheme for carrying USB Power Delivery Messages. This
encoding assumes a dedicated DC connection, identified as the CC wire, which is used for sending PD Messages.
Preamble
0
1
0
1
0
1
Sync-1
0
1
0
0
0
Sync-1
1
1
0
0
0
1
1
Data In
BMC
Figure 4. BMC Example
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RT1731
1UI
Y9
Y8
Y7
Y6
Y5
Y4
Y3
Y2
Y1
X1 X2
X3
X4
X12
0.5UI
X14
X13
Figure 5. BMC Tx ‘ZERO’ Mask
1UI
Y9
Y8
Y7
Y6
Y5
Y4
Y3
Y2
Y1
X1 X2 X3
X4
X5
X6X7 X8 X9
X10
0.5UI
X11
X12
X14
X13
Figure 6. BMC Tx ‘ONE’ Mask
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RT1731
Table 1. BMC Tx Mask Definition and X Values
BMC TC Mask Definition, X Values
Parameter
Symbol
Value
Unit
Left Edge of Mask
X1Tx
0.015
UI
X2Tx point
X2Tx
0.07
UI
X3Tx point
X3Tx
0.15
UI
X4Tx point
X4Tx
0.25
UI
X5Tx point
X5Tx
0.35
UI
X6Tx point
X6Tx
0.43
UI
X7Tx point
X7Tx
0.485
UI
X8Tx point
X8Tx
0.515
UI
X9Tx point
X9Tx
0.57
UI
X10Tx point
X10Tx
0.65
UI
X11Tx point
X11Tx
0.75
UI
X12Tx point
X12Tx
0.85
UI
X13Tx point
X13Tx
0.93
UI
Right Edge of Mask
X14Tx
0.985
UI
Table 2. BMC Tx Mask Definition and Y Values
BMC TC Mask Definition, Y Values
Parameter
Symbol
Typ
Unit
Lower Bound of Outer Mask
Y1Tx
0.075
V
Lower Bound of Inner Mask
Y2Tx
0.075
V
Y3Tx Point
Y3Tx
0.15
V
Y4Tx Point
Y4Tx
0.325
V
Inner Mask Vertical Midpoint
Y5Tx
0.5625
V
Y6Tx Point
Y6Tx
0.8
V
Y7Tx Point
Y7Tx
0.975
V
Y8Tx Point
Y8Tx
1.04
V
Upper Bound of Outer Mask
Y9Tx
1.2
V
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RT1731
Absolute Maximum Ratings
(Note1)
VCON1/VCON2/CCIN ----------------------------------------------------------------------------------------------- 0.3V to 22V
SCL/SDA ---------------------------------------------------------------------------------------------------------------- 0.3V to 6V
Power Dissipation, PD @ TA = 25C
WDFN-8L 2x2 ---------------------------------------------------------------------------------------------------------- 2.19W
WL-CSP-8B 0.96x1.64 (BSC) -------------------------------------------------------------------------------------- 0.93W
Package Thermal Resistance
(Note 2)
WDFN-8L 2x2, JA ---------------------------------------------------------------------------------------------------- 45.5°C/W
WDFN-8L 2x2, JC ---------------------------------------------------------------------------------------------------- 11.5°C/W
WL-CSP-8B 0.96x1.64 (BSC), JA -------------------------------------------------------------------------------- 106.5°C/W
Lead Temperature (Soldering, 10 sec.) -------------------------------------------------------------------------- 260C
Junction Temperature ------------------------------------------------------------------------------------------------ 150C
Storage Temperature Range --------------------------------------------------------------------------------------- 65C to 150C
ESD Susceptibility
(Note 3)
HBM (Human Body Model)
VCON1/VCON2/CCIN ----------------------------------------------------------------------------------------------- 8kV
Others -------------------------------------------------------------------------------------------------------------------- 2kV
Recommended Operating Conditions
(Note 4)
Supply Input Voltage ------------------------------------------------------------------------------------------------- 3V to 5.5V
Ambient Temperature Range--------------------------------------------------------------------------------------- 40C to 85C
Junction Temperature Range -------------------------------------------------------------------------------------- 40C to 125C
Electrical Characteristics
(VDD = 5V, TA = 25C, unless otherwise specified)
Parameter
Symbol
Test Conditions
Min
Typ
Max
Unit
BMC Signaling
Bit rate
Maximum difference between the
bit-rate during the part of the
packet following the Preamble and
the reference bit-rate.
Time from the end of last bit of a
Frame until the start of the first bit
of the next Preamble.
Time before the start of the first bit
of the Preamble when the
transmitter shall start driving the
line.
f BitRate
VCONN = 3V to 5.5V
270
300
330
Kbps
pBitRate
VCONN = 3V to 5.5V
--
--
0.25
%
tInterFrameGap
VCONN = 3V to 5.5V
25
--
--
s
tStartDrive
VCONN = 3V to 5.5V
1
--
1
s
VCONN = 3V to 5.5V
--
--
23
s
BMC Common Normative
Time to cease driving the line after
t
the end of the last bit of the Frame. EndDriveBMC
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RT1731
Parameter
Symbol
Test Conditions
Min
Typ
Max
Unit
Fall Time
tFall
VCONN = 3V to 5.5V
300
--
--
ns
Time to cease driving the line after
the final high-to-low transition
tHoldLowBMC
VCONN = 3V to 5.5V
1
--
--
s
Rise Time
tRise
VCONN = 3V to 5.5V
300
--
--
ns
Voltage Swing
vSwing
VCONN = 3V to 5.5V
1.05
1.125
1.2
V
Transmitter Output Impedance
zDriver
VCONN = 3V to 5.5V
33
--
75
Cable Termination
RA
VCONN = 3V to 5.5V
800
--
1200
Receiver Input Impedance
zBmcRx
VCONN = 3V to 5.5V
1
--
--
M
Isupply
Typical values measured
at VCONN1 or VCONN2 = 5V
--
9.5
--
mA
Isupply-by
Typical values measured
at VCONN1 or VCONN2 = 5V
--
1.6
--
mA
BMC Receiver Normative
BIST Mode
Supply Current
Stand-by Mode
Supply Current
Note 1. Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These
are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in
the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions may affect
device reliability.
Note 2. JA is measured under natural convection (still air) at TA = 25°C with the component mounted on a high
effective-thermal-conductivity four-layer test board on a JEDEC 51-7 thermal measurement standard. JC is measured
at the exposed pad of the package.
Note 3. Devices are ESD sensitive. Handling precaution is recommended.
Note 4. The device is not guaranteed to function outside its operating conditions.
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RT1731
Typical Application Circuit
Electronically Marked Cable with VCONN connected through the cable (Passive cable application)
VBUS
VBUS
CC
VCONN
CC
VCONN
Type-C Plug
RT1731
VCON2 VCON1
CCIN
GND
SCL
SDA
Type-C Plug
NC
NC
(Exposed Pad)
GND
GND
Electronically Marked Cable with SOP’ at both ends (Passive cable application)
VBUS
VBUS
CC
CC
VCONN
Type-C Plug
VCONN
RT1731
VCON2 VCON1
CCIN
GND
SCL
NC
SDA
NC
(Exposed Pad)
RT1731
VCON2 VCON1
CCIN
GND
SCL
NC
SDA
NC
Type-C Plug
(Exposed Pad)
GND
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RT1731
Application Information
Start of Packet Sequence Prime (SOP’)
The SOP’ ordered set is defined as : two Sync-1
K-codes followed by two Sync-3 K-codes
K-code Number
K-code in Code Table
1
Sync-1
2
Sync-1
3
Sync-3
4
Sync-3
Communication is assigned shall only detect and
communicate with packets starting with SOP’’ and shall
Discard any other packets.
A Port needing to communicate with such a Cable Plug,
Attached between a Port Pair will be able to
communicate using packets starting with SOP’ and
SOP’’ to communicate with the Cable Plugs and
packets starting with SOP to communicate with its Port
Partner.
A Cable Plug capable of SOP’ Communications shall
only detect and communicate with packets starting with
Structured VDM
SOP’.
defines the use of bits Bit[14:0] in the Structured VDM
Header. The fields in the Structured VDM Header are
defined in Table.
A DFP or Source needing to communicate with a Cable
Plug capable of SOP’ Communications, attached
between a Port Pair will be able to communicate using
both packets starting with SOP’ to communicate with
the Cable Plug and starting with SOP to communicate
with its Port Partner. The DFP or Source shall
co-ordinate SOP and SOP’ Communication so as to
avoid collisions.
Setting the VDM Type field to 1 (Structured VDM)
The following rules apply to the use of Structured VDM
messages :
Start of Packet Sequence Double Prime (SOP’’)
The SOP’’ ordered set is defined as the following
sequence of K-codes : Sync-1, Sync-3, Sync-1, Sync-3
K-code Number
K-code in Code Table
1
Sync-1
2
Sync-3
3
Sync-1
4
Sync-3
A Cable Plug capable of SOP’’ Communication, shall
have a SOP’ Communication capability in the other
Cable Plug. No cable shall only support SOP’’
Communication. A Cable Plug to which SOP’’
Bit(s)
Structured VDMs shall only be used when an
Explicit Contract is in place with the following
exception :
Prior to establishing an Explicit Contract a Source
may issue Discover Identity messages, to a Cable
Plug using SOP’ Packets, as an Initiator.
Only the DFP shall be an Initiator of Structured
VDMs except for the Attention Command that shall
only be initiated by the UFP.
Only the UFP or a Cable Plug shall be a Responder
to Structured VDMs.
Structured VDMs shall not be initiated or responded
to under any other circumstances.
A DFP or UFP which does not support Structured
VDMs shall ignore any Structured VDMs received.
A Command sequence shall be interruptible e.g.
due to the need for a message sequence using SOP
Packets.
Field
Description
Bit[31:16]
Standard or Vendor ID (SVID) Unique 16-bit unsigned integer, assigned by the USB-IF
Bit[15]
VDM Type
1 = Structured VDM
Structured VDM Version
Version number of the structured VDM (not this specification
Version)
00b = Version 1.0 (shall not be used)
01b = Version 2.0
Values = 10, 11 are Reserved and shall not be used
Bit[14:13]
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RT1731
Bit(s)
Field
Description
Reserved
For Commands 0…15 shall be set to 0 and shall be ignored
SVID specific commands (16…31) defined by the SVID.
Object Position
For the enter mode, exit mode and attention commands
(requests/responses) :
000b = Reserved and shall not be used.
001b…110b = Index into the list of VDOs to identify the desired
Mode VDO
111b = Exit all Active Modes (equivalent of a power on reset).
Shall only be used with the exit mode command.
Commands 0…3, 7…15 :
000b
001b…111b = Reserved and shall not be used.
SVID specific commands (16…31) defined by the SVID.
Bit[7:6]
Command Type
00b = REQ (Request from initiator port)
01b = ACK (Acknowledge response from responder port)
10b = NAK (Negative acknowledge response from responder port)
11b = BUSY (Busy response from responder port)
Bit[5]
Reserved
0 : Reserved, shall not be used
Command (Note 5)
0 = Reserved, shall not be used
1 = Discover identity
2 = Discover SVIDs
3 = Discover modes
4 = Enter mode
5 = Exit mode
6 = Attention
7-15 = Reserved, shall not be used
16..31 = SVID specific commands
Bit[12:11]
Bit[10:8]
Bit[4:0]
Note 5 : In the case where a SID is used the modes are defined by a standard. When a VID is used the modes are
defined by the Vendor.
Discover Identity
The Discover Identity Command is provided to enable an Initiator (DFP) to identify its Port Partner and for an
Initiator (Source or DFP) to identify the attached Cable Plug (Responder).
The SVID in the Discover SVIDs Command shall be set to the PD SID by both the Initiator and the Responder for
this Command.
The Discover Identity Command sent back by the Responder contains an ID Header, a Cert Stat VDO and some
Type specific VDOs which depend on the Product Type. This specification defines the following Type specific
VDOs :
Header
No. of Data Objects = 4-71
VDM
Header
ID
Header
Cert Stat VDO
Product VDO
0..32 Product
Type VDO(s)
1. Only Data objects defined in this specification can be sent as part of the Discover Identity Command.
2. The following sections define the number and content of the VDOs for each Product Type.
The Number of Data Objects field in the Message Header in the Discover Identity Command NAK and BUSY
responses shall be set to 1 since they shall not contain any VDOs.
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ID Header
The ID Header contains the vendor ID corresponding to the Power Delivery Product.
Bit(s)
Description
Bit[31]
USB communications capable as USB host :
0b : Otherwise
1b : The product is capable of enumerating USB devices.
Bit[30]
USB communications capable as a USB device :
0b : Otherwise
1b : The product is capable of being enumerated as a USB device.
Bit[29:27]
Product type (cable plug) :
000b : Undefined
001b…010b : Reserved, shall not be used.
011b : Passive cable
100b : Active cable
101b…111b : Reserved, shall not be used.
Bit[26]
Modal operation supported :
0 : Otherwise
1 : The product supports modal operation.
Bit[25:16]
0 : Reserved, shall not be used
Bit[15:0]
16-bit unsigned integer. USB vendor ID
Cert Stat VDO
The Cert Stat VDO contains the Test ID (TID) allocated by USB-IF during certification.
Bit(s)
Bit[31: 0]
Description
32-bit unsigned integer, XID
Product VDO
The Product VDO contains identity information relating to the product.
Bit(s)
Description
Bit[31:16]
16-bit unsigned integer. USB Product ID
Bit[15:0]
16-bit unsigned integer. bcdDevice
PD2 Cable VDO
The Cable VDO defined in this section shall be sent when the Product Type is given as Passive or Active Cable.
Bit(s)
Field
Description
Bit[31:28]
Cable HW Version
0000b..1111b assigned by the VID owner
Bit[27:24]
Cable Firmware Version
0000b..1111b assigned by the VID owner
Bit[23:21]
VDO Version
Version number of the VDO
Values 000b, 001b, … 111b are Reserved
Reserved
0 = Reserved, shall not be used
Type-C to Type-A/B/C
00b = Type-A
01b = Type-B
10b = Type-C
11b = Captive
Bit[20]
Bit[19:18]
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RT1731
Bit(s)
Field
Description
Type-C to Plug/Receptacle
0 = Plug
1 = Receptacle (not valid when B19..18 set to
Type-C or Captive)
Cable Latency
0000b : Reserved
0001b : < 10ns (~1m)
0010b : 10ns to 20ns (~2m)
0011b : 20ns to 30ns (~3m)
0100b : 30ns to 40ns (~4m)
0101b : 40ns to 50ns (~5m)
0110b : 50ns to 60ns (~6m)
0111b : 60ns to 70ns (~7m)
1000b : 1000ns (~100m)
1001b : 2000ns (~200m)
1010b : 3000ns (~300m)
1011b ….1111b : Reserved
Includes latency of electronics in active cable
Cable Termination Type
00b = Both ends Passive, VCONN not required
01b = Both ends Passive, VCONN required
10b = One end Active, one end passive,
VCONN required
11b = Both ends Active, VCONN required
Bit[10]
SSTX1 Directionality Support
0 = Fixed
1 = Configurable
Bit[9]
SSTX2 Directionality Support
0 = Fixed
1 = Configurable
Bit[8]
SSRX1 Directionality Support
0 = Fixed
1 = Configurable
Bit[7]
SSRX2 Directionality Support
0 = Fixed
1 = Configurable
VBUS Current Handling Capability
00b = VBUS not through cable
01b = 3A
10b = 5A
11b = Reserved
Bit[4]
VBUS through cable
0 = No
1 = Yes
Bit[3]
SOP” controller present
1 = SOP” controller present
0 = No SOP” controller present
USB Super speed Signaling Support
000b = USB 2.0 only
001b = USB3.1 Gen1
010b = USB3.1 Gen1 and Gen2
011b.. 111b = Reserved
Bit[17]
Bit[16:13]
Bit[12:11]
Bit[6:5]
Bit[2:0]
PD3 Passive Cable VDO
The Cable VDO defined in this section shall be sent when the Product Type is given as Passive or Active Cable.
Bit(s)
Field
Description
Bit[31:28]
HW Version
0000b..1111b assigned by the VID owner
Bit[27:24]
Firmware Version
0000b..1111b assigned by the VID owner
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RT1731
Bit(s)
Field
Description
VDO Version
Version number of the VDO (not this
specification version) :
Version 1.0 = 000b
Values 001b…111b are Reserved and shall not
be used
Reserved
0= Reserved, shall not be used
USB Type-C plug to USB
Type-C/Captive
00b = Reserved, shall not be used
01b = Reserved, shall not be used
10b = USB Type-C
11b = Captive
Reserved
0= Reserved, shall not be used
Cable Latency
0000b : Reserved, shall not be used
0001b : < 10ns (~1m)
0010b : 10ns to 20ns (~2m)
0011b : 20ns to 30ns (~3m)
0100b : 30ns to 40ns (~4m)
0101b : 40ns to 50ns (~5m)
0110b : 50ns to 60ns (~6m)
0111b : 60ns to 70ns (~7m)
1000b : 70ns (> ~7m)
1001b ….1111b : Reserved, shall not be used
Includes latency of electronics in active cable
Cable Termination Type
00b = VCONN not required. Cable plugs that
only support discover identity commands shall
set these bits to 00b.
01b = VCONN required
10b…11b = Reserved, shall not be used
Bit[10:9]
Maximum VBUS Voltage
Maximum Cable VBUS voltage :
00b = 20V
01b = 30V
10b = 40V
11b = 50V
Bit[8:7]
Reserved
00b = Reserved, shall not be used
Bit[6:5]
VBUS Current Handling Capability
00b = Reserved, shall not be used
01b = 3A
10b = 5A
11b = Reserved, shall not be used
Bit[4:3]
Reserved
00b = Reserved, shall not be used
USB Super speed Signaling Support
000b = USB 2.0 only, no Super-Speed support
001b = USB 3.1 Gen1
010b = USB 3.1 Gen1 and Gen2
011b…111b = Reserved, shall not be used
See USB Type-C 1.2 for definitions
Bit[23:21]
Bit[20]
Bit[19:18]
Bit[17]
Bit[16:13]
Bit[12:11]
Bit[2:0]
PD3 Active Cable VDO
Bit(s)
Field
Description
Bit[31:28]
HW Version
0000b..1111b assigned by the VID owner
Bit[27:24]
Firmware Version
0000b..1111b assigned by the VID owner
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RT1731
Bit(s)
Field
Description
VDO Version
Version number of the VDO (not this
specification version) :
Version 1.0 = 000b
Version 1.1 = 001b
Values 010b…111b are Reserved and shall not
be used
Reserved
0 = Reserved, shall not be used
USB Type-C plug to USB
Type-C/Captive
00b = Reserved, shall not be used
01b = Reserved, shall not be used
10b = USB Type-C
11b = Captive
Reserved
0 = Reserved, shall not be used
Cable Latency
0000b : Reserved, shall not be used
0001b : < 10ns (~1m)
0010b : 10ns to 20ns (~2m)
0011b : 20ns to 30ns (~3m)
0100b : 30ns to 40ns (~4m)
0101b : 40ns to 50ns (~5m)
0110b : 50ns to 60ns (~6m)
0111b : 60ns to 70ns (~7m)
1000b : 70ns (> ~7m)
1001b ….1111b : Reserved, shall not be used
Includes latency of electronics in active cable
Cable Termination Type
00b…01b = Reserved, shall not be used
10b = One end Active, one end passive,
VCONN required
11b = Both ends Active, VCONN required
Bit[10:9]
Maximum VBUS Voltage
Maximum Cable VBUS voltage :
00b = 20V
01b = 30V
10b = 40V
11b = 50V
Bit[8]
SBU Supported 0 = SBUs
connections supported
0 = SBUs connections supported
1 = SBU connections are not supported
1 = SBU connections are not
supported
When SBU supported = 1 this bit shall be
Ignored.
When SBU supported = 0 :
0 = SBU is passive
1 = SBU is active
VBUS Current Handling Capability
When VBUS through cable is “No”, Reserved,
shall not be used.
When VBUS though Cable is “Yes” :
00b = Reserved, shall not be used
01b = 3A
10b = 5A
11b = Reserved, shall not be used
Bit[4]
VBUS Through Cable
0 = No
1 = Yes
Bit[3]
SOP” Controller Present
0 = No SOP” controller present
1 = SOP” controller present
Bit[23:21]
Bit[20]
Bit[19:18]
Bit[17]
Bit[16:13]
Bit[12:11]
Bit[7]
Bit[6:5]
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RT1731
Bit(s)
Bit[2:0]
Field
Description
Reserved
00b = Reserved, shall not be used
PD3 Active Cable VDO2 with VDO Version = 1.2
The Cable VDO defined in this section shall be sent when the Product Type is given as Active Cable and VDO
version = 1.2.
Bit(s)
Field
Description
Bit[31:24]
Maximum Operating Temperature
The maximum internal operating temperature. It
may or may not reflect the plug’s skin
temperature.
Bit[23:16]
Shutdown Temperature
The temperature at which the cable will go into
thermal shutdown so as not to exceed the
allowable plug skin temperature.
Bit[15:6]
Reserved
0…0b = Reserved, shall not be used
Bit[5]
USB 2.0 Supported
0 = USB2.0 supported
1 = USB2.0 not supported
Bit[4]
SuperSpeed Supported
0 = USB3.1 Super-Speed supported
1 = USB3.1 Super-Speed not supported
Bit[3]
SuperSpeed Lanes Supported
0 = One Lane
1 = Two Lanes
Bit[2]
Reserved
0 = Reserved, shall not be used
SuperSpeed Signaling
00b = USB 3.1 Gen1
01b = USB 3.1 Gen2
10 to 11b = Reserved, shall not be used.
Bit[1:0]
Discover SVIDs Responder VDO
The Discover SVIDs Command is used by an Initiator to determine the SVIDs for which a Responder has Modes.
The Discover SVIDs Command is used in conjunction with the Discover Modes Command in the Discovery Process
to determine which Modes a device supports.
Bit(s)
Field
Description
Bit[31:16]
SVID n
16-bit unsigned integer, assigned by the USB-IF
or 0x0000 if this is the last VDO and the
Responder supports an even number of SVIDs.
Bit[15:0]
SVID n+1
16-bit unsigned integer, assigned by the USB-IF
or 0x0000 if this is the last VDO and the
Responder supports an odd number of SVIDs.
Discover MODES
The Discover Modes Command is used by an Initiator to determine the Modes a Responder supports for a given
SVID. The SVID in the Discover Modes Command shall be set to the SVID for which Modes are being requested by
both the Initiator and the Responder for this Command.
Header
No. of Data Objects = 4
VDM Header
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April 2021
Mode 1
Mode 2
Mode 3
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RT1731
PD3.0 Get Status
The Get_Status Message is sent by a Port to request Port Partner’s present state. The Get_Status Message may
also be sent to an Active Cable to get its present status using SOP’/SOP’’.The Active Cable shall respond by
returning a Status Message.
The Status Message shall be sent in response to a Get_Status Message. The Contents of the Status Message
depends on the target of the Get_Status Message. When sent to SOP the Status Message returns the status of the
Port’s Port Partner. When sent to SOP’ or SOP’’ the Status Message returns the status of the Active Cable’s Plug.
Extended Header
Data Size = 2
SDB
(2-byte block)
SOP’ Status Data Block
Offset
Field
Value
0
Internal Temp
Unsigned
Int
1
Flags
Bit field
Description
Active Cable Plug’s internal temperature in celcious degree.
0 = Feature not supported
1 = Temperature is less than 2 celcious degree.
2 to 255 = Temperature in celcious degree.
Bit0 = Thermal shutdown
Bit1..Bit7 = Reserved and shall be set to zero
Thermal Considerations
The junction temperature should never exceed the
absolute maximum junction temperature TJ(MAX), listed
under Absolute Maximum Ratings, to avoid permanent
damage to the device. The maximum allowable power
dissipation depends on the thermal resistance of the IC
package, the PCB layout, the rate of surrounding
airflow, and the difference between the junction and
ambient temperatures. The maximum power
dissipation can be calculated using the following
formula :
PD(MAX) = (TJ(MAX) - TA) / JA
where TJ(MAX) is the maximum junction temperature,
TA is the ambient temperature, and JA is the
junction-to-ambient thermal resistance.
effective-thermal-conductivity four-layer test board.The
maximum power dissipation at TA = 25°C can be
calculated as below :
PD(MAX) = (125°C - 25°C) / (45.5°C/W) = 2.19W for a
WDFN-8L 2x2 package.
PD(MAX) = (125°C - 25°C) / (106.5°C/W) = 0.93W for a
WL-CSP-8B 0.96x1.64 (BSC) package.
The maximum power dissipation depends on the
operating ambient temperature for the fixed TJ(MAX)
and the thermal resistance, JA. The derating curves in
Figure 7 allows the designer to see the effect of rising
ambient temperature on the maximum power
dissipation.
For continuous operation, the maximum operating
junction temperature indicated under Recommended
Operating
Conditions
is
125°C.
The
junction-to-ambient thermal resistance, JA, is highly
package dependent. For a WDFN-8L 2x2 package, the
thermal resistance, JA, is 45.5°C/W on a standard
JEDEC 51-7 high effective-thermal-conductivity
four-layer test board. For a WL-CSP-8B 0.96x1.64
(BSC) package, the thermal resistance, JA, is
106.5°C/W on a standard JEDEC 51-7 high
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is a registered trademark of Richtek Technology Corporation.
DS1731-02
April 2021
RT1731
Layout Considerations
Maximum Power Dissipation (W)1
2.5
Four-Layer PCB
2.0
PCB layout is very important for designing e-marked
IC (RT1731) circuits.
WDFN-8L 2x2
Connect VCON1/VCON2 pins with bypass capacitor,
1.5
and as near the pins as possible.
1.0
The exposed pad of the chip should be connected to
a large ground plane for thermal consideration.
0.5
WL-CSP-8B 0.96x1.64 (BSC)
Keep the CCIN traces away from those sensing pins
(D+, D-, SSTX+, SSTX-, SSRX+, SSRX-, SBU).
0.0
0
25
50
75
100
125
Ambient Temperature (°C)
Figure 7. Derating Curve of Maximum Power
Dissipation
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RT1731
Outline Dimension
Symbol
Dimensions In Millimeters
Dimensions In Inches
Min
Max
Min
Max
A
0.700
0.800
0.028
0.031
A1
0.000
0.050
0.000
0.002
A3
0.175
0.250
0.007
0.010
b
0.200
0.300
0.008
0.012
D
1.950
2.050
0.077
0.081
D2
1.000
1.250
0.039
0.049
E
1.950
2.050
0.077
0.081
E2
0.400
0.650
0.016
0.026
e
L
0.500
0.300
0.020
0.400
0.012
0.016
W-Type 8L DFN 2x2 Package
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DS1731-02
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RT1731
Dimensions In Millimeters
Symbol
Dimensions In Inches
Min
Max
Min
Max
A
0.500
0.600
0.020
0.024
A1
0.170
0.230
0.007
0.009
b
0.240
0.300
0.009
0.012
D
1.600
1.680
0.063
0.066
D1
E
1.200
0.920
0.047
1.000
0.036
0.039
E1
0.400
0.016
e
0.400
0.016
8B WL-CSP 0 96x1 64 Package (BSC)
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RT1731
Footprint Information
Package
V/W/U/XDFN2*2-8
Footprint Dimension (mm)
Number of
Pin
P
A
B
C
D
Sx
Sy
M
8
0.50
2.80
1.20
0.80
0.30
1.30
0.70
1.80
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Tolerance
±0.05
is a registered trademark of Richtek Technology Corporation.
DS1731-02
April 2021
RT1731
Package
Number of
WL-CSP0.96x1.64-8(BSC)
Pin
8
Footprint Dimension (mm)
Type
NSMD
SMD
e
0.400
A
B
0.240
0.340
0.270
0.240
Tolerance
±0.025
Richtek Technology Corporation
14F, No. 8, Tai Yuen 1st Street, Chupei City
Hsinchu, Taiwan, R.O.C.
Tel: (8863)5526789
Richtek products are sold by description only. Richtek reserves the right to change the circuitry and/or specifications without notice at any time. Customers should
obtain the latest relevant information and data sheets before placing orders and should verify that such information is current and complete. Richtek cannot assume
responsibility for use of any circuitry other than circuitry entirely embodied in a Richtek product. Information furnished by Richtek is believed to be accurate and
reliable. However, no responsibility is assumed by Richtek or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may
result from its use. No license is granted by implication or otherwise under any patent or patent rights of Richtek or its subsidiaries.
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is a registered trademark of Richtek Technology Corporation.
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