CalDigit TS4 Thunderbolt 4 Dock Teardown

[Don’t forget to check out the other 50+ Thunderbolt 4 Docks]

Thanks to longtime reader /u/Chaftalie, we have some photos of the CalDigit TS4 docking station internals. [Photos used with permission]

CalDigit TS4 feature summary:

  • 230W PSU
  • 1 TB4 rear-facing upstream port with 98W power delivery
  • 2x TB4 ports (40Gb/s / 15W)
  • 1x DP 1.4 port
  • Dual monitor support:
    • 2x TB4 or 1x TB4 + 1x DP 1.4
    • 1x 8K60, 2x 5K60, 1x 4K144, 1x 3440x1440p180 or 1x 1440p240
  • 1x USB-C 3.2 Gen2 (10Gb/s / 20W)
  • 2x USB-C 3.2 Gen2 (10Gb/s / 7.5W)
  • 5x USB-A 3.2 Gen2 (10Gb/s / 7.5W)
  • 3x 3.5mm audio (1x trrs front, 2x trs rear)
  • Intel i225 2.5Gb/s Ethernet (only works with TB3/TB4 systems)
  • UHS-II SD Card reader
  • K-lock


An adhered rubber foot stabilizes the Dock in vertical orientation.
Removing 4 long bolts and 4 small screws reveals the main aluminum finned chassis and milled aluminum I/O caps
Front I/O cap removal reveals a PCB sandwich fastened with metal stand-offs
Rear I/O cap removed
Main assembly slides out of the shell
4 more screws to remove on the bottom
The bottom piece reveals 7 heat-sink thermal pads


Primary PCB – top
Primary PCB – bottom
Secondary PCB – top
Secondary PCB – bottom

PCB investigation

The Primary PCB includes the key chips like the Intel JHL8440 TB4 controller, USB-C PMICs, DC-DC converters, bulk capacitors, flash RAM and USB hub chips. It also houses the upstream TB4 connector, two downstream TB4 connectors, a DisplayPort 1.4 connector, two USB-C 3.2 Gen2 connectors and a DC power barrel jack. It is connected to the secondary PCB with a rigid 50-pin board-to-board connector.

The secondary PCB includes 2 USB hub chips, aCard reader chip, an Intel i225 2.5Gb Ethernet chip, two audio chips, and various USB PMICs. It also houses, the RJ-45 Ethernet jack, five USB-A 3.2 Gen2 ports, three 3.5mm audio jacks, SDcard reader, and an additional USB-C 3.2 Gen2 port. Below I’ve listed the key components:

Physical Topology:

  • TB4 Upstream port
    • Intel JHL8440
      • TB4 downstream port #1
      • TB4 downstream port #2
      • 50-pin connector (PCIe x1 channel to secondary PCB)
        • Intel i225 2.5GbE
          • RJ-45 Ethernet jack with integrated transformers
      • Pericom/Diodes Inc. PI3DBS12212A 12Gbps 4->2 mux/demux
        • DisplayPort 1.4
      • Fresco Logic/ParadeTech FL5801-2Q2 5-port USB2 port expander
        • TI T65982DMC Dock management controller
          • SPI connections to flash chips
      • Fresco Logic/ParadeTech FL5500-2F0 6-port hub controller #1
        • USB-C port #1 (front)
        • USB-C port #2 (front)
        • 50-pin connector to secondary PCB (2x USB 3.2 Gen2 channels)
          • Fresco Logic/ParadeTech FL5500-2F0 hub controller #2
            • 2x USB-A 3.2 Gen2 ports (rear)
            • USB-C port #3 (rear)
            • CMedia CM6533 Audio #1 (top of PCB)
              • 2x 3.5mm trs jacks (rear)
          • Fresco Logic/ParadeTech FL5500-2F0 hub controller #3
            • 2x USB-A 3.2 Gen2 ports (rear)
            • USB-A 3.2 Gen2 port (front)
            • Genesys Logic GL3231S USB 3.1 Gen1 SDCard reader
              • SD card slot
              • microSD card slot
            • CMedia CM6533 Audio #2 (bottom of PCB)
              • 1x 3.5mm trrs jack (front)

Comments and final thoughts

As always, CalDigit’s construction and design is impressive. CalDigit is not afraid to use exposed fasteners making repairs simple. Unlike its competitors, CalDigit is serious about power delivery by providing a 230W PSU and placing USB-C PMICs and DC-DC convertors across both PCBs close to the ports. Users should have no problems connecting multiple external HDD, SSD, 10GbE, cellphones, or other devices to draw the full rated power.

The lack of an MST chipset is surprising with a device offering so much functionality as it limits users to only two displays (additional displays can be connected via DisplayLink USB video extender technology). Still, 1x 8K60 or 2x 5K60 support is more than enough for most folks in the target market – many of CalDigit’s customers are Mac users where MST isn’t supported anyway. Curiously, there are two CMedia CM6533 audio chipsets – one for the rear ports and one for the front. According to CalDigit’s documentation, front and rear can’t be used simultaneously so I don’t understand why there are two chips. The CM6533 documentation states that it has configurable topology for headset (trrs) vs mic/speakers (2x trs) and I2C/GPIO support, so presumably a hardware switch inside the 3.5mm jack could be used change modes. Perhaps firmware updates will enable all 3 audio jacks to work together to support surround speakers or subwoofers.

Unlike the competing Lenovo which is cross-marketed to USB-C and Thunderbolt 4 laptops, CalDigit does not include a USB-based Ethernet chip to run alongside the PCIe-based Intel i225 2.5GbE solution. This means USB-C systems won’t get Ethernet functionality. But the dual PCB design enables CalDigit to bring future devices with different port configurations to market with minimal re-designs. Perhaps we’ll see a device with 1GbE or even 10GbE.


7 thoughts on “CalDigit TS4 Thunderbolt 4 Dock Teardown

  1. Hi Danchar, wonderful teardown post.
    Ethernet port is provided by intel I255, it seems like the PCIe Gen3 x1 link is included in this board-to-board special header, just similiar to the OWC mini Stack.
    There might be possibility to mod this dock into ……. some kind of NVMe device or maybe x1 bandwith eGPU?


  2. Thanks for this teardown, really helps to understand what I might be buying 🙂

    One question, though: Do you have a sense for how much power this dock uses on its own? So far, I’ve been able to keep the power usage of my laptop and everything attached to it fairly minimal, but with this hefty 230W power brick, I’m slightly afraid that this dock will add tens of Watts to this, even when nothing’s attached. Do you have any idea? Same question for the Lenovo TB4 dock you did a teardown of, btw, that’s also one I’m considering.


    • On paper, all the chips on the PCB could consume up to 20W, but I doubt they do in typical operation. It’s probably more like 5-10 watts in typical use with keyboard/monitors/mouse.

      Connecting PSU/monitor/mouse/keyboard direct to the laptop will use less power, but it’s only going to be that 5-10W difference – not a big deal in the grand scheme of things.


    • Thanks for sharing that. I didn’t have the Caldigit in hand for testing and was just supplied the photos for analysis and I missed some details.

      I went back and looked at the traces to the USB ports and your USB tree is correct for the 2nd-level USB hubs so I’ve updated my post accordingly.


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