The resolution of a typical 2.76 inch round TFT display is 480x480 pixels. This is a square aspect ratio (1:1) that fits the circular shape, giving you a crisp and clear image for applications like smartwatches, dashboards, or industrial control panels. The pixel density comes out to roughly 246 pixels per inch (PPI), which is calculated by dividing the diagonal resolution (sqrt(480² + 480²) ≈ 678.8 pixels) by the 2.76 inch diagonal. That PPI is comparable to many smartphone displays, meaning text and icons look sharp even at close viewing distances. For example, the 2.76 inch 480x480 round tft display from DisplayModule uses this exact resolution, and it’s a common spec in the industry because it balances clarity with power efficiency.
But resolution alone doesn’t tell the whole story. The 480x480 pixel count means the display has 230,400 individual pixels (480 times 480). In a round form factor, the usable area is about 78.5% of a full square, so roughly 180,000 pixels are actually visible in the circular viewport. The rest are hidden behind the bezel or mask. This is a key detail for designers: you’re not getting a full 480x480 grid in the visible circle because the corners are cut off. The active area diameter is typically around 49.5 mm (1.95 inches), with the overall module size being about 70 mm in diameter including the frame. The pixel pitch, which is the distance between adjacent pixels, works out to roughly 0.103 mm (103 micrometers). That’s tight enough that you won’t see individual pixels from normal viewing distances—say, 30 cm away.
Let’s break down the numbers in a table to make it concrete:
| Parameter | Value | Notes |
|---|---|---|
| Resolution | 480 x 480 pixels | Square aspect ratio |
| Diagonal size | 2.76 inches (70.1 mm) | Measured across the circular glass |
| Pixel density (PPI) | ~246 PPI | Based on diagonal resolution |
| Total pixels | 230,400 | 480 x 480 |
| Visible pixels (approx.) | ~180,000 | Due to circular mask |
| Pixel pitch | 0.103 mm | Center-to-center distance |
| Active area diameter | 49.5 mm (1.95 inches) | Typical for 2.76-inch round TFT |
| Module outer diameter | ~70 mm | Includes bezel and FPC |
Now, why 480x480 specifically? It’s not arbitrary. This resolution is a sweet spot for driving MIPI (Mobile Industry Processor Interface) and RGB parallel interfaces, which are common in small round displays. The 480x480 format fits neatly into an 8-bit or 16-bit color depth system, letting you display 262,000 colors (18-bit RGB) or 16.7 million colors (24-bit RGB) depending on the driver IC. Most 2.76 inch round TFTs use a driver like the ST7701S or ILI9341, which support 480x480 natively. The refresh rate is usually 60 Hz, but some modules can go up to 90 Hz if you’re using a high-speed MIPI interface. The pixel clock for 480x480 at 60 Hz is roughly 27 MHz (480 x 480 x 60 = 13.8 million pixels per second, but with blanking intervals it’s higher). That’s low enough to run on a microcontroller like an ESP32 or STM32 without extra hardware.
Let’s talk about real-world performance. At 480x480, the display can show a full circle of content without scaling artifacts. For example, a watch face with minute marks around the edge will look smooth because the 480 pixels across the diameter give you about 1.5 pixels per degree of arc. That’s enough for crisp lines and small text at 8-point font size. The contrast ratio is typically 1000:1 for IPS (In-Plane Switching) panels, which are common in these round TFTs. Viewing angles are usually 80 degrees in all directions, meaning you can see the image clearly from the side. Brightness varies by model, but standard backlight LEDs push 300 to 500 nits. For outdoor use, 500 nits is marginal; you’d want 800+ nits for direct sunlight. The power draw at 480x480 with a typical backlight is around 150-200 mW at 50% brightness, which is reasonable for battery-powered devices.
One common misconception is that resolution equals image quality. It doesn’t. The 480x480 resolution is fine for most applications, but the color depth and interface speed matter more. For instance, if you’re using an 8-bit RGB interface, you’ll get 262,000 colors, which is fine for icons and text but might show banding in gradients. A 16-bit interface gives 65,536 colors, and 24-bit gives 16.7 million. The 2.76 inch round TFT I mentioned earlier often supports 16-bit color via MIPI, which is a good balance. The pixel format is usually RGB565 (5 bits red, 6 bits green, 5 bits blue), which uses 16 bits per pixel. That means the frame buffer for a full 480x480 image is 460,800 bytes (480 x 480 x 2 bytes). That’s a lot of RAM for a microcontroller; you might need external SRAM or a display controller with built-in framebuffer. Most driver ICs have 512 KB to 1 MB of internal RAM, so they can handle it.
Let’s compare 480x480 to other common round display resolutions to give you context:
| Resolution | Diagonal | PPI | Total Pixels | Common Use |
|---|---|---|---|---|
| 240x240 | 1.28 inches | ~265 | 57,600 | Smartwatches, fitness trackers |
| 360x360 | 1.5 inches | ~339 | 129,600 | High-end smartwatches |
| 480x480 | 2.76 inches | ~246 | 230,400 | Dashboards, industrial panels |
| 540x540 | 3.0 inches | ~254 | 291,600 | Automotive, medical devices |
Notice that the 2.76 inch round TFT has a lower PPI than a 1.28-inch 240x240 display, but the larger size makes it more readable. The 480x480 resolution is actually overkill for some applications—you could run a 240x240 image scaled up without much loss, but the native resolution avoids blur. The interface bandwidth is also a factor. With MIPI DSI (Display Serial Interface), you can use 1 or 2 data lanes, each running at 500 Mbps to 1 Gbps. For 480x480 at 60 Hz with 24-bit color, you need about 345 Mbps (480 x 480 x 24 x 60 = 331.8 Mbps, plus overhead). That’s easily handled by a single lane at 500 Mbps. If you’re using RGB parallel interface, you need 18 or 24 data lines, which eats up GPIO pins on your microcontroller. That’s why MIPI is preferred for round displays—it reduces pin count.
Another angle: the physical pixel layout. In a round TFT, the pixels are arranged in a square grid, but the circular mask cuts off the corners. This means the edge pixels are partially hidden, which can cause aliasing if you’re drawing fine lines near the rim. To avoid that, you need to use anti-aliasing or a circular clipping algorithm. The 480x480 resolution gives you enough pixels to implement a smooth circular border without jagged edges. The pixel size is 0.103 mm, so the visible circle has a radius of about 24.75 mm, which is 240 pixels. That’s plenty for a smooth curve. In contrast, a 240x240 round display would have only 120 pixels per radius, making the edge look blocky.
Let’s get into the driver IC specifics. The ST7701S, which is common in 2.76 inch round TFTs, supports 480x480 natively. It has a built-in framebuffer of 720 KB, which is enough for 480x480 at 24-bit color (691,200 bytes). The IC uses MIPI DSI with 1 or 2 lanes, and it supports 18-bit, 16-bit, and 24-bit color modes. The typical command set includes things like memory write, display on/off, and gamma correction. The gamma curve is adjustable, which lets you tweak the contrast for different lighting conditions. The response time is around 25 ms (rise + fall), which is fine for static images but might show ghosting for fast animations. For video, 60 Hz is the standard, but you can push it to 90 Hz if you reduce the blanking intervals. The backlight is usually driven by a separate PWM pin, with a frequency of 1 kHz to 20 kHz to avoid flicker.
Now, about the physical dimensions. The 2.76 inch round TFT module is typically 70 mm in diameter, with a thickness of 2.5 to 3.5 mm including the backlight. The glass itself is about 1.1 mm thick, with a polarizer on top. The active area is 49.5 mm in diameter, leaving a 10.25 mm border around the edge for the bezel. The FPC (Flexible Printed Circuit) cable is usually 15 to 20 mm long, with a 0.5 mm pitch connector. The pinout varies by manufacturer, but common signals include MIPI data lanes, clock, reset, chip select, backlight enable, and PWM. Some modules also include a capacitive touch panel, which adds 0.5 mm to the thickness and requires an I2C interface. The touch resolution is often 480x480 as well, but it’s interpolated from a matrix of sensors.
From a practical standpoint, the 480x480 resolution on a 2.76 inch round TFT is a solid choice for projects that need a balance of size, clarity, and interface simplicity. It’s not the highest PPI out there—some 1.5-inch round displays hit 339 PPI—but the larger size makes it easier to read from a distance. The 2.76 inch form factor is popular in automotive dashboards, where you need to show gauges and warnings without squinting. The 480x480 resolution lets you display a speedometer needle with smooth movement, or a map with readable street names. For industrial applications, it’s used in control panels where you need to show status icons and numeric values. The round shape is also aesthetic, fitting into circular cutouts in enclosures.
One more data point: the color gamut. Most 2.76 inch round TFTs use a TN (Twisted Nematic) or IPS panel. TN panels have a narrower viewing angle (60 degrees) but faster response time (10 ms). IPS panels have wider viewing angles (80 degrees) and better color accuracy, but slower response time (25 ms). The color gamut is typically 60% to 70% of the NTSC standard, which is enough for most applications but not for professional photography. The luminance uniformity is usually within 80% across the active area, meaning the edges might be slightly dimmer than the center. The contrast ratio is 800:1 to 1000:1 for IPS, and 500:1 to 800:1 for TN. The operating temperature range is typically -20°C to 70°C, which is fine for indoor use but might need a heater for extreme cold.
To sum up the technical details: the 480x480 resolution on a 2.76 inch round TFT gives you a sharp image with a PPI of 246, a pixel pitch of 0.103 mm, and a total pixel count of 230,400. The interface is usually MIPI DSI or RGB parallel, with a driver IC like ST7701S. The color depth ranges from 16-bit to 24-bit, and the refresh rate is 60 Hz standard. The physical size is 70 mm diameter with a 49.5 mm active area. The backlight brightness is 300-500 nits, and power consumption is around 150-200 mW. These specs make it a versatile option for a wide range of projects, from smartwatches to industrial panels. The key is to match the resolution to your content and interface capabilities. If you’re driving it with a microcontroller, make sure you have enough RAM for the framebuffer, or use a display with built-in memory. The 2.76 inch round TFT is a proven design that’s been used in many commercial products, and the 480x480 resolution is a standard that’s here to stay.