What is the size of a 2.76 inch round display module?

When someone asks about the size of a 2.76 inch round display module, the direct answer is that the display diagonal measures exactly 2.76 inches, which translates to about 70.1 millimeters. But that number alone doesn’t tell you much about the physical footprint, the active area, or how it fits into a product design. You need to look at the outer diameter, the bezel width, the thickness, and the resolution to really understand what you’re dealing with. A 2.76 inch round display module, like the 2.76 inch 480x480 round tft display, is a compact circular panel often used in smart wearables, smart home devices, automotive dashboards, and industrial control panels. The size is compact enough to fit into a small enclosure but large enough to show readable text, icons, and graphics. Let’s break down the real dimensions, the active area, resolution specifics, pixel density, and how these numbers affect your design choices.

Physical Outer Diameter and Bezel Size

The outer diameter of a typical 2.76 inch round TFT display module is not exactly 2.76 inches. The 2.76 inch refers to the diagonal of the circular active area, not the physical outer edge of the module. The module itself includes a bezel or a frame that holds the glass and the backlight. For the 2.76 inch 480x480 round TFT display, the outer diameter of the module is approximately 75.2 millimeters, or about 2.96 inches. That’s about 0.2 inches larger than the active area diagonal. The bezel width around the active area is roughly 2.5 millimeters on each side. This bezel is necessary for structural support, bonding the display to the PCB, and housing the driver IC and flex cable. If you’re designing a product that needs a flush fit, you need to account for that extra 5 millimeters in total diameter. The thickness of the module, including the backlight and the glass, is typically around 2.8 to 3.2 millimeters, depending on whether you choose a standard or a high-brightness version. The flex cable extends from one side, usually about 15 to 20 millimeters in length, and that adds to the overall footprint in your enclosure.

Active Area Dimensions

The active area is the part of the display that actually lights up and shows content. For a circular display, the active area is a circle with a diameter of 2.76 inches, which is 70.1 millimeters. But because it’s a circle, the width and height are both the same: 70.1 millimeters. That’s the diameter. The total area of the active region is about 3,860 square millimeters. That’s roughly 5.98 square inches. Compare that to a square display of the same diagonal, which would have an area of about 7.6 square inches. The circular shape loses about 21% of the area compared to a square of the same diagonal. That’s important for UI design because you have less real estate to work with, especially in the corners. The active area is surrounded by a black matrix border that is about 0.5 to 1.0 millimeter wide, depending on the manufacturing tolerances. That border is not part of the active area but is part of the glass. The total glass diameter is usually around 72 to 73 millimeters.

Resolution and Pixel Density

The resolution is 480 by 480 pixels, which is a square resolution mapped onto a circular active area. That means the pixel count is 230,400 pixels total. The pixel density is calculated by dividing the number of pixels along the diameter by the diameter in inches. So 480 pixels divided by 2.76 inches gives you about 174 pixels per inch (PPI). That’s a decent pixel density for a display of this size. For comparison, a typical smartphone display has a PPI of around 300 to 400, but for a round wearable display, 174 PPI is sufficient for clear text, icons, and basic graphics. The pixel pitch, which is the distance between the centers of two adjacent pixels, is about 0.146 millimeters. That’s 146 micrometers. Each subpixel (red, green, blue) is about 48 micrometers wide. The display uses a standard RGB stripe arrangement, which provides good color reproduction. The aperture ratio, which is the percentage of the pixel area that actually emits light, is typically around 65% to 70% for TFT panels of this size. That affects brightness and contrast.

Viewing Angle and Optical Performance

The viewing angle for this type of display is usually specified as 80 degrees in all directions, meaning you can view the display from up to 80 degrees off the perpendicular axis without significant color shift or contrast loss. That’s a total viewing cone of 160 degrees. The contrast ratio is typically 800:1 to 1000:1, which is standard for IPS or TN panels. The brightness is usually around 300 to 400 nits for standard indoor use, but you can get high-brightness versions that go up to 600 nits for outdoor readability. The color gamut is about 70% of the NTSC standard, which means it can display about 70% of the colors in the NTSC color space. That’s typical for a mid-range TFT display. The response time is around 10 to 15 milliseconds, which is fine for static images and slow animations but not ideal for fast video playback. The refresh rate is typically 60 Hz, which is standard for most TFT panels.

Interface and Driver IC

The interface for this display is MIPI DSI (Display Serial Interface) with 2 lanes, which is a high-speed serial interface commonly used in mobile devices and embedded systems. The driver IC is usually a single-chip solution like the ILI9881C or a similar controller. The MIPI interface supports a maximum data rate of 500 Mbps per lane, so the total bandwidth is 1 Gbps. That’s enough to drive 480x480 pixels at 60 Hz with 24-bit color depth. The display also supports RGB interface as an alternative, but MIPI is more common for round displays because it reduces the number of wires. The flex cable has a 24-pin or 30-pin connector, depending on the specific model. The operating voltage is 3.3 volts for the logic and 2.8 volts for the analog. The backlight is driven by a separate LED driver that requires 3.0 to 3.3 volts and draws about 20 to 30 milliamps at typical brightness. The total power consumption is around 150 to 200 milliwatts for the display and backlight combined, depending on the brightness setting.

Mechanical Mounting and Integration

The module usually comes with a metal frame or a plastic bezel that has mounting holes or tabs. The outer diameter of the frame is about 75.2 millimeters, and the thickness is about 3.0 millimeters. The weight is around 8 to 10 grams. The flex cable exits from the bottom or the side, and it’s usually about 15 millimeters wide and 0.3 millimeters thick. The cable has a stiffener at the connector end to make it easier to insert into a ZIF connector. The recommended mounting method is to use a gasket or a foam tape to hold the display in place and to provide shock absorption. The display is sensitive to pressure on the active area, so you need to avoid clamping forces on the glass. The typical operating temperature range is -20 to +70 degrees Celsius, and the storage temperature range is -30 to +80 degrees Celsius. That makes it suitable for most indoor and outdoor applications, but not for extreme environments like automotive engine compartments.

Comparison with Other Round Display Sizes

To give you a better perspective, here’s a table comparing the 2.76 inch round display with other common round display sizes:

Display Size (Diagonal)	Active Area Diameter (mm)	Module Outer Diameter (mm)	Resolution (pixels)	Pixel Density (PPI)	Typical Application
1.28 inch	32.5	36.0	240x240	186	Smartwatch
1.54 inch	39.1	42.5	240x240	155	Wearable
2.76 inch	70.1	75.2	480x480	174	Smart home, dashboard
3.4 inch	86.4	92.0	480x480	141	Industrial panel
4.0 inch	101.6	108.0	600x600	150	Automotive

As you can see, the 2.76 inch size sits in a sweet spot between the small wearable displays and the larger industrial panels. It offers a good balance of readability and compactness. The 480x480 resolution gives you four times the pixel count of a 240x240 display, which is a significant improvement for text rendering and graphic detail. The pixel density of 174 PPI is higher than the 1.54 inch and 3.4 inch displays, so the image looks sharper. The module outer diameter of 75.2 millimeters means you need an enclosure that is at least 76 millimeters in diameter to accommodate the display with a small gap.

Backlight and Brightness Options

The backlight is typically an LED array with 6 to 8 white LEDs arranged in series or parallel. The typical forward voltage is 3.0 to 3.3 volts, and the current is 20 to 30 milliamps per LED. The total backlight power is about 60 to 100 milliwatts at typical brightness. The brightness can be adjusted via PWM (pulse width modulation) on the backlight enable pin. The typical PWM frequency is 1 kHz to 10 kHz to avoid flicker. The standard brightness is 300 nits, but you can order a high-brightness version that uses more LEDs or higher current to achieve 600 nits. The high-brightness version consumes about 150 to 200 milliwatts for the backlight alone. The color temperature of the backlight is usually 6500K to 7500K, which is a cool white. If you need a warmer color temperature, you can request a custom backlight with different LED bins. The uniformity of the backlight is typically 80% or better, meaning the brightness variation across the active area is less than 20%.

Touch Panel Integration

Some versions of the 2.76 inch round display module come with a capacitive touch panel bonded to the glass. The touch panel is a circular sensor with a diameter of about 72 millimeters. It uses a mutual capacitance sensing method with a typical resolution of 10 touch points. The touch controller is usually a single-chip solution like the FT6336 or a similar IC. The interface for the touch panel is I2C, with a typical address of 0x38. The touch panel adds about 0.5 to 1.0 millimeter to the total thickness of the module. The touch panel is optically clear with a transparency of 85% to 90%. The cover glass is usually made of strengthened glass with a thickness of 0.7 to 1.1 millimeters. The touch panel is sensitive to gloved fingers and can be configured for wet conditions. The operating voltage for the touch controller is 3.3 volts, and the power consumption is about 5 to 10 milliwatts.

Signal Timing and Driving Requirements

The display requires a specific set of timing parameters to operate correctly. The horizontal sync pulse width is typically 2 to 4 pixels, the horizontal back porch is 10 to 20 pixels, and the horizontal front porch is 10 to 20 pixels. The vertical sync pulse width is 2 to 4 lines, the vertical back porch is 10 to 20 lines, and the vertical front porch is 10 to 20 lines. The total horizontal period is about 500 pixels, and the total vertical period is about 500 lines, giving a total of 250,000 pixels per frame. At 60 Hz, the pixel clock frequency is about 15 MHz. The MIPI DSI interface uses a data rate of about 250 Mbps per lane, which is within the typical range. The display supports both video mode and command mode, but for round displays, video mode is more common because it allows for continuous refresh. The display also supports partial update mode, which can reduce power consumption for static images.

Environmental and Reliability Testing

The module is designed to meet industrial standards for reliability. It undergoes temperature cycling tests from -20 to +70 degrees Celsius for 100 cycles. It is also tested for humidity at 85% relative humidity at 60 degrees Celsius for 240 hours. The display is resistant to electrostatic discharge up to 8 kV for air discharge and 4 kV for contact discharge. The vibration test is 10 to 500 Hz at 1.5 G for 30 minutes per axis. The drop test is 1 meter onto a concrete floor. The display is also tested for sunlight readability, which is measured by the contrast ratio under direct sunlight. The typical sunlight readability is acceptable for outdoor use with a brightness of 400 nits or more. The display is also tested for UV resistance, but it is not recommended for prolonged direct sunlight exposure without a UV filter.

Cost and Availability

The unit price for the 2.76 inch 480x480 round TFT display module varies depending on the volume and the options. For a single unit, the price is typically around $25 to $35. For quantities of 100 to 500 units, the price drops to about $15 to $20 per unit. For quantities of 1000 units or more, the price can be as low as $10 to $12 per unit. The touch panel adds about $5 to $8 per unit. The lead time is usually 4 to 6 weeks for standard orders, and 8 to 12 weeks for custom orders with specific backlight or touch panel configurations. The display is available from multiple distributors and manufacturers, including the one linked above. The module is RoHS compliant and CE certified.

Design Considerations for Round Displays

When designing a product around a round display, you need to consider the unique challenges of circular UI. The active area is a circle, so you cannot use rectangular UI elements without clipping. You need to design your UI to fit within the circle, which often means using radial menus, circular gauges, and centered text. The resolution of 480x480 pixels gives you a radius of 240 pixels, so you can draw smooth circles and arcs. The pixel density of 174 PPI means that text at 12 points is about 20 pixels tall, which is readable. The display supports 24-bit color, so you can use full-color graphics. The driver IC supports hardware rotation, so you can orient the display in any direction. The MIPI interface is fast enough to support smooth animations at 60 fps. The power consumption is low enough for battery-powered devices, especially if you use a low refresh rate or partial update mode.

Common Applications and Use Cases

This display is commonly used in smart home devices like smart thermostats, smart speakers, and smart displays. It is also used in automotive applications for gauge clusters, climate control panels, and rearview mirror displays. In industrial settings, it is used for control panels, test equipment, and medical devices. The round shape is aesthetically pleasing and fits well in modern product designs. The display is also used in wearable devices like smartwatches and fitness trackers, although the 2.76 inch size is larger than typical smartwatch displays. The 480x480 resolution is a good match for displaying high-quality graphics and text. The display is also used in gaming devices, such as handheld consoles and arcade machines. The round shape is also used in novelty items like clocks, mirrors, and decorative panels.

Technical Support and Documentation

The manufacturer provides a datasheet that includes all the mechanical drawings, electrical specifications, timing diagrams, and register settings. The datasheet is typically 20 to 30 pages long. They also provide a software driver for popular microcontrollers like STM32, ESP32, and Raspberry Pi. The driver includes initialization code, basic drawing functions, and examples for MIPI DSI communication. The manufacturer also provides a 3D CAD model of the module in STEP format for mechanical integration. The technical support team is available via email and phone, and they can help with custom modifications like different backlight colors, touch panel options, or flex cable lengths. The display is also available with an optional cover lens that has anti-glare or anti-fingerprint coating.

Future Trends and Developments

The round display market is growing, and manufacturers are developing higher resolution panels with the same form factor. There are already prototypes of 2.76 inch round