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Enabling SuperSpeed USB and Beyond


VL821 - Super Speed USB 3.1 Gen2 Hub Controller with USB-C and USB-PD Support


VIA Lab’s VL821 is an advanced USB-PD Hub with USB 3.1 Gen2 and USB Power Delivery 2.0/3.0 support. VL821 features the world’s first unified USB Hub and PD Controller design, supporting advanced USB-PD functionality such as USB-C Bridge for USB Authentication and USB-PD Firmware Update for downstream USB-PD devices. VL821 features 1x upstream port and 4x downstream ports, all of which support 10Gbps USB 3.1 Gen2 operation. The downstream ports can support any combination of SuperSpeed Plus (10Gbps), SuperSpeed (5Gbps), High Speed (480Mbps), Full Speed (12Mbps), and Low Speed (1.5Mbps) devices. VL821’s integrated USB 2.0 hub features Multiple Transaction Translators, providing increased bandwidth and performance when multiple Full Speed devices are simultaneously used.

VL821 comes in two variants: VL821-Q8 utilizes the QFN88 10x10x0.85 mm package while the VL821-Q7 utilizes the smaller QFN76 9x9x0.85mm package. The larger QFN88 variant features integrated 10Gbps Muxes for the Upstream Facing Port and two Downstream Facings Ports whereas the smaller QFN76 variant does not. The integrated 10Gbps Muxes are ideal for Data-Only USB-C applications that would otherwise require an external Mux, with the advantage of potential board area savings and improved signal integrity. If additional data-only USB-C Ports are needed, separate CC Logic and Mux solutions such as VL160 are available. For USB-PD support on either the UFP or DFP, VL821 features an integrated USB Type-C Port Master (TCPM) which can be connected to the VP230 USB Type-C Port Controller.

VL821 features flexible firmware architecture, providing a framework for custom functions in addition to in-field updates. Various parameters including USB configuration, PD configuration, Tx equalization setting, and GPIO behavior are changeable via firmware. VL821 also features an optional per-port configurable USB Charging Controller for charging various devices such as smartphones and tablets, an optional USB Billboard Device for USB-PD Alternate Mode applications, and an optional USB HID endpoint to support Media Control Buttons such as Play/Pause, Volume Up/Down, etc.

VL821-based hub devices work under Windows, Mac OS X, and various Linux kernels without additional drivers. VL821-based hub devices are also compatible with non-x86 devices and platforms that support USB hub functions such as smart phones, tablets, and set-top boxes. It is well suited for all USB hub applications such as standalone USB hubs, Notebook/Ultrabook docking stations/port-replicators, desktop PC front panel, motherboard on-board hub, and USB hub compound devices.

Block Diagram

Key Features

  • USB 3.1 Compliant
    - Compliant to Universal Serial Bus 3.1 Specification
    - SuperSpeed Plus USB (USB 3.1 Gen2)
    - Compliant to Universal Serial Bus 2.0 Specification
    - USB 2.0 Hub Supports MTT
    - Supports Simultaneous Operation of Any Combination of SuperSpeed Plus, SuperSpeed, High-Speed, Full-Speed, and Low-Speed Devices - Supports USB Power Saving Features such as Link Power Management, Ux States, Selective Suspend, and Function Suspend - In-house USB PHY employs advanced CMOS process for low power consumption
  • USB Type-C 1.0 Rev 1.2 Compliant
    - Compliant to USB Type-C Specification Rev 1.2
    - Compliant to USB Type-C Port Controller Interface Specification Rev 1.0
    - Supports up to 5x Independently Configurable TCPC
    - VL821-Q8: Integrated 10Gbps Mux for UFP and 2x DFP
    - Requires External CC Logic Controller for Orientation Detection/Vconn (Such as VP225)
    - Additional USB-C DFP support requires separate CC Logic and Mux (Such as VL160)
  • USB Power Delivery 2.0/3.0
    - Compliant to USB Power Delivery 2.0 Specification Rev 1.2
    - USB-IF Certified: Charging UFP with Alternate Mode Support
    - VL821 TCPM & VP230 TCPC (TID: 1010026)
    - Compliant to USB Power Delivery 3.0
    - Supports Fast Role Swap
    - Supports USB-C Bridge
  • Integrated USB Devices
    - USB Billboard Class 1.21 Device
    Implemented as a USB 2.0 Virtual Device
    Configurable Behavior – Expose When Necessary / Always Present / Disabled
    - USB HID Class Device Implemented as a USB 2.0 Virtual Device, Facilitates FW Update or Media Control Buttons Configurable Behavior – Always Present / Disabled
    - USB-C Bridge Class Device
    Implemented as a USB 2.0 Virtual Device. Facilitates USB to PD Bridge Functionality
    Configurable Behavior – Always Present / Disabled
  • Full Sideband Signal Support
    - Supports Any Combination of Individual or Ganged Mode Over-Current for All Ports
    - Supports PWM LED Status Lights
    - SPI Interface for Firmware
    - Firmware Upgradable over USB
  • Comprehensive USB Battery Charging Support
    - Supports USB Battery Charging Specification v1.2 (SDP, CDP, DCP)
    - Support for Vendor Specific Charging Modes eg. Apple 2.4A, Samsung, etc.
    - Supports YD/T 1591-2009
    - Supports Stand-Alone Charging when System is Suspend, Shut Down, or Disconnected
    - Any Combination of DFPs can be Configured to Support USB Battery Charging
  • Power and Package
    - Requires 3.3V and 1.05V Inputs
    - VL821-Q8: QFN 88L green package (10x10x0.85 mm)
    - VL821-Q7: QFN 76L green package (9x9x0.85 mm)
    - 25MHz Xtal