The size of an HDMI to MIPI DSI connector is not a one-size-fits-all answer, because it depends heavily on the specific adapter board or cable assembly you're using. Typically, the physical connector on the adapter board for the HDMI input is a standard HDMI Type A female port, which measures approximately 13.9mm in width, 4.45mm in height, and 8.9mm in depth (excluding the metal shield). On the MIPI DSI side, the connector is usually a fine-pitch FPC (Flexible Printed Circuit) connector, often 0.5mm or 0.3mm pitch, with a width that can range from 15mm to 30mm depending on the number of lanes (e.g., 4-lane or 2-lane) and the specific pin count. For example, a common 4-lane MIPI DSI connector with 30 pins on a 0.5mm pitch has a body width of around 20mm to 25mm, and a height of about 2.5mm to 3.5mm. The overall board size for a typical adapter, like the hdmi to 4 lane mipi dsi adapter, often measures around 50mm x 40mm or 60mm x 30mm, but this varies by manufacturer and features like onboard voltage regulators or signal buffers.
To get into the nitty-gritty, the HDMI connector itself is governed by the HDMI specification, which defines the Type A connector's physical dimensions as 13.9mm ± 0.1mm in width, 4.45mm ± 0.1mm in height, and the shell depth is typically 8.9mm from the mating face to the back of the shell. The pin pitch inside the HDMI connector is 0.5mm, with 19 pins arranged in two rows. This is a well-established standard, so you can rely on these numbers for any HDMI port on these adapter boards. The MIPI DSI connector, however, is a different beast. It's usually a surface-mount FPC connector from manufacturers like Hirose, JAE, or Molex, with a pitch of 0.5mm, 0.4mm, or 0.3mm. For a 4-lane MIPI DSI interface, you typically need a minimum of 30 pins (including power, ground, clock, and data lanes), but some designs use 40 or 50 pins for additional I2C, SPI, or backlight control signals. The physical dimensions of these connectors vary: a 0.5mm pitch, 30-pin FPC connector has a body width of about 22.5mm (calculated as 0.5mm x 30 pins plus 7.5mm for the side locks), a depth of 6.5mm to 7.0mm, and a height of 2.0mm to 3.0mm. For a 0.3mm pitch, 40-pin connector, the width shrinks to around 14.5mm, but the pin alignment is more critical.
The overall board size is where the real variation comes in. A basic HDMI to MIPI DSI adapter board, like the one designed for 4-lane MIPI DSI displays, often has a PCB (Printed Circuit Board) that measures 50mm x 40mm (2 inches x 1.6 inches) or 55mm x 35mm. This includes the HDMI connector on one edge, the MIPI DSI FPC connector on the opposite edge, and supporting components like a TFP401 or LT8918 chip (for HDMI to LVDS conversion), a voltage regulator (e.g., 3.3V and 1.8V outputs), and possibly a crystal oscillator. The board thickness is typically 1.6mm (standard FR4), but some compact designs use 0.8mm or 1.0mm for flexibility. The mounting holes are often 3.2mm in diameter, spaced at 45mm x 30mm or 50mm x 35mm centers. If the adapter includes a cable assembly, the cable itself is usually a flat ribbon cable with 30 or 40 conductors, 0.5mm pitch, and a length of 100mm to 200mm, with a width of 15mm to 20mm.
Let's break down the dimensions with a concrete example. Take the adapter board from DisplayModule, which is a common choice for hobbyists and engineers. The board measures 52mm x 38mm, with a height of 12mm (including the HDMI connector's protrusion). The HDMI Type A connector is on the short edge, adding 8.9mm to the board's depth. The MIPI DSI connector is a 0.5mm pitch, 30-pin FPC connector, with a body width of 22.5mm and a height of 2.5mm. The board has four mounting holes at the corners, each 3.2mm in diameter, with a spacing of 44mm x 30mm. The total weight is around 10 grams without cables. For comparison, a more compact adapter from another vendor might use a 0.3mm pitch, 40-pin connector, reducing the board width to 40mm, but increasing the pin count for additional features like touch or backlight control. The HDMI connector's dimensions remain constant, but the board layout can shift the connector's position by 2mm to 3mm to accommodate larger capacitors or inductors.
Data from datasheets and teardowns reveals that the MIPI DSI connector's size is tightly coupled to the display's resolution and lane count. For a 4-lane MIPI DSI interface supporting 1080p at 60Hz, the connector must handle 8 data lanes (4 for data, 1 for clock, plus power and ground), which typically requires 30 to 40 pins. The FPC connector's pitch is often 0.5mm for easier assembly, but 0.3mm is used for high-density designs. The table below summarizes common connector sizes for HDMI to MIPI DSI adapters:
| Component | Type | Width (mm) | Height (mm) | Depth (mm) | Pitch (mm) | Pin Count |
|---|---|---|---|---|---|---|
| HDMI Type A | Female | 13.9 | 4.45 | 8.9 | 0.5 | 19 |
| MIPI DSI FPC (0.5mm pitch) | 30-pin | 22.5 | 2.5 | 6.5 | 0.5 | 30 |
| MIPI DSI FPC (0.3mm pitch) | 40-pin | 14.5 | 2.0 | 5.5 | 0.3 | 40 |
| Adapter Board (typical) | PCB | 52 | 12 | 38 | N/A | N/A |
| Ribbon Cable (30-pin) | Flat | 16 | 1.0 | 100-200 | 0.5 | 30 |
The physical size also affects thermal management. The HDMI to MIPI DSI conversion chip, such as the LT8918 or TFP401, can dissipate 0.5W to 1.5W depending on the resolution and frame rate. The board's size must accommodate a small heatsink or thermal pad, which adds 1mm to 2mm to the height. For example, the LT8918B chip, which is common in these adapters, has a package size of 7mm x 7mm (QFN-56), and the board layout requires at least 10mm x 10mm of copper area for heat dissipation. The voltage regulator (e.g., MP1584 or AMS1117) adds another 5mm x 5mm area. So, the board's 52mm x 38mm size is not arbitrary; it's driven by the need to fit these components with adequate spacing for signal integrity and thermal relief.
Another factor is the connector's orientation. On most adapter boards, the HDMI connector is mounted on the edge, parallel to the board's surface, while the MIPI DSI connector is also on the edge but often perpendicular to the board's plane to allow the FPC cable to bend away. This orientation affects the overall height of the assembly. For instance, if the HDMI connector is on the top edge, the board's height becomes 12mm (including the connector's protrusion), but if the MIPI DSI connector is on the bottom edge, the cable's bend radius (typically 5mm to 10mm) adds to the total space required. In a compact enclosure, you might need 15mm to 20mm of clearance above the board for the cable.
From a practical standpoint, the size of the connector dictates the minimum enclosure dimensions. If you're integrating this adapter into a product, you need to account for the HDMI connector's 13.9mm width plus 2mm for the housing cutout, and the MIPI DSI connector's 22.5mm width plus 3mm for the FPC cable's strain relief. The board's mounting holes require 5mm of clearance from the edges. So, a typical enclosure for a 52mm x 38mm board would be 60mm x 45mm x 15mm (internal dimensions). This is a common size for many display driver modules, but custom designs can be smaller if you use a 0.3mm pitch connector and a more compact chip like the LT8918B in a smaller package.
The data also shows that the connector's size influences the signal integrity. For a 4-lane MIPI DSI interface running at 1Gbps per lane, the FPC connector's impedance must be controlled to 100 ohms differential. The connector's physical dimensions, especially the pin-to-pin spacing, affect the crosstalk and insertion loss. A 0.5mm pitch connector has a typical differential impedance of 90 to 100 ohms, but a 0.3mm pitch connector can have higher crosstalk due to tighter spacing. The board's layout must include impedance-matched traces, which require wider trace widths (e.g., 0.15mm for 0.5mm pitch, 0.1mm for 0.3mm pitch) and ground planes. This adds to the board's overall size because you need more space for the vias and routing.
In terms of manufacturing tolerances, the HDMI connector's dimensions are specified to ±0.1mm, but the MIPI DSI connector's tolerance can be ±0.2mm for the body width and ±0.1mm for the height. The FPC cable's thickness is typically 0.3mm to 0.5mm, with a tolerance of ±0.05mm. These tolerances mean that the actual size of the connector on a production board can vary slightly, but it's usually within the datasheet limits. For example, a 0.5mm pitch, 30-pin connector from Hirose (FH12 series) has a body width of 22.5mm ±0.2mm, a depth of 6.5mm ±0.2mm, and a height of 2.5mm ±0.1mm. The HDMI connector from TE Connectivity (type A) has a width of 13.9mm ±0.1mm, a height of 4.45mm ±0.1mm, and a depth of 8.9mm ±0.1mm.
For a specific use case, like connecting a Raspberry Pi to a 5-inch MIPI DSI display, the adapter board's size is critical for fitting in a custom case. The DisplayModule adapter, for instance, is designed to be compact enough to fit behind the display panel, with a thickness of 12mm including the HDMI connector. The MIPI DSI connector's 22.5mm width means the FPC cable must be routed carefully to avoid bending too sharply. The board's 52mm x 38mm size fits within the typical 5-inch display's backlight area, which is about 70mm x 50mm. The mounting holes align with the display's standoffs, which are often 45mm x 30mm apart. This is a common pattern for many small TFT displays.
The cable assembly's size also matters. A 30-pin, 0.5mm pitch FPC cable is typically 16mm wide and 0.3mm thick, with a length of 100mm to 200mm. The cable's bend radius is about 5mm, so you need at least 10mm of space for the cable to loop around. If you're using a 40-pin, 0.3mm pitch cable, the width is 14mm, but the bend radius is smaller at 3mm. The connector's locking mechanism, usually a flip-lock or slide-lock, adds 1mm to 2mm to the height. The overall assembly height, including the board and cable, can be 15mm to 20mm, depending on the cable routing.
In summary, the size of the HDMI to MIPI DSI connector varies by design, but the HDMI side is fixed at 13.9mm x 4.45mm x 8.9mm, while the MIPI DSI side ranges from 14.5mm to 22.5mm in width, 2.0mm to 3.5mm in height, and 5.5mm to 7.0mm in depth. The board size is typically 50mm to 60mm in length and 30mm to 40mm in width, with a thickness of 1.6mm. These dimensions are driven by the chipset, pin count, and thermal requirements, and they determine the enclosure size and integration complexity. For a reliable connection, always check the datasheet of the specific adapter board, like the one from DisplayModule, which provides precise mechanical drawings for the connector and PCB.