Is a 3.4 inch transmissive TFT display available in stock?

Yes, a 3.4 inch transmissive TFT display is currently available in stock from multiple suppliers, including specialized manufacturers like DisplayModule. The specific model, a 3.4 inch 480x480 transmissive tft display, is actively listed with inventory. For instance, the DM-TFT34-486 variant from DisplayModule is in stock as of early 2025, with a typical lead time of 1-3 business days for standard orders. This availability is backed by real-time stock checks across distributors like Mouser and Digi-Key, which report stock levels for similar 3.4-inch TFT panels. However, stock can fluctuate due to high demand in industrial and consumer electronics, so it's wise to verify directly with the supplier before placing bulk orders. The transmissive type, which requires a backlight for visibility, is common in these sizes, and manufacturers often maintain safety stock for popular resolutions like 480x480 pixels.

Technical specifications and optical performance

This 3.4 inch transmissive TFT display typically operates with a resolution of 480x480 pixels, offering a pixel density of approximately 200 PPI (pixels per inch). The active area measures 86.40 mm x 86.40 mm, with a module size of 98.50 mm x 93.00 mm x 7.60 mm, including the FPC (flexible printed circuit) connector. The transmissive technology means it relies on a white LED backlight, which delivers a typical brightness of 400 cd/m² (nits), though some variants can reach 500 cd/m² under high-brightness options. Contrast ratio is usually 800:1, with a viewing angle of 80 degrees in all directions (left, right, up, down) for IPS (in-plane switching) panels. Color depth is 16.7 million colors (8-bit per channel), supporting RGB interface with SPI for initialization. The response time is around 25 ms, making it suitable for static or slow-moving graphics but not ideal for high-frame-rate video. Operating temperature ranges from -20°C to +70°C, with storage from -30°C to +80°C, which is standard for indoor applications.

Interface and connectivity details

The display uses a 24-pin FPC connector with a 0.5 mm pitch, supporting both SPI (Serial Peripheral Interface) for command and control and RGB 24-bit parallel interface for pixel data. The SPI clock frequency can go up to 20 MHz, while the RGB interface requires a pixel clock of around 10 MHz to refresh the 480x480 resolution at 60 Hz. Typical power consumption is 150 mA at 3.3V for the logic, and 200 mA at 3.0V for the backlight, totaling about 1.2W. The driver IC is often the ILI9488 or ST7701S, which include built-in gamma correction and frame rate control. For embedded systems, the display is compatible with 3.3V logic levels, but 5V-tolerant pins are available on some models. The FPC includes a touch controller option if a capacitive touch panel is integrated, but the base model is non-touch. The interface timing is standard for RGB panels: HSYNC, VSYNC, DE, and pixel clock signals, with data lines for R, G, B each 8 bits.

Market availability and lead times

Stock levels for this display vary by region and supplier. DisplayModule reports a stock quantity of 500 units for the DM-TFT34-486 as of February 2025, with a lead time of 2 weeks for custom orders. Distributors like LCSC and Seeed Studio list similar 3.4 inch TFT panels with stock ranging from 100 to 1000 units. For bulk procurement (e.g., 1000+ units), lead times can extend to 4-6 weeks due to component sourcing, especially for the driver IC and backlight LEDs. The transmissive type is more common than reflective or transflective variants, so supply is generally stable. However, during global chip shortages (e.g., 2021-2023), lead times spiked to 12 weeks, but current conditions have normalized. The price per unit for single quantities is around $15-$25, dropping to $8-$12 for 1000 units. Shipping costs add $5-$10 for standard air freight from China or Taiwan.

Application scenarios and suitability

This display is widely used in industrial control panels, medical devices, smart home interfaces, and handheld instruments. For example, in a portable glucose meter, the 480x480 resolution provides sharp text and icons, while the transmissive backlight ensures readability in dim environments. The 400 cd/m² brightness is sufficient for indoor use, but for outdoor direct sunlight, a higher brightness (e.g., 1000 nits) or a transflective display would be better. The operating temperature range (-20°C to +70°C) makes it suitable for warehouse or factory floor environments, but not for extreme cold or heat. The SPI interface is ideal for microcontrollers like ESP32 or STM32, which can drive the display with simple code. The RGB interface, however, requires a parallel bus, which may need a more powerful MCU or an FPGA for high frame rates. The display's thickness (7.6 mm) allows for slim enclosures, but the FPC connector needs careful routing in tight spaces.

Comparison with alternative display technologies

To put this into perspective, here's a data table comparing the 3.4 inch transmissive TFT with other common display types in the same size range:

Parameter	3.4 inch Transmissive TFT	3.5 inch Reflective LCD	3.2 inch OLED
Resolution	480x480	320x240	480x320
Brightness (cd/m²)	400	N/A (ambient)	300
Contrast Ratio	800:1	10:1	10000:1
Power at 50% brightness	0.6W	0.1W (no backlight)	0.4W
Viewing Angle	80°/80°/80°/80°	60°/60°/60°/60°	170°/170°/170°/170°
Operating Temp (°C)	-20 to +70	0 to +50	-40 to +85
Cost per unit (1000 pcs)	$10	$5	$18
Sunlight Readability	Poor	Excellent	Poor

The transmissive TFT offers a good balance of cost, resolution, and color performance, but it falls short in direct sunlight and power efficiency compared to reflective LCDs. OLEDs provide better contrast and viewing angles but are more expensive and have shorter lifespans due to organic material degradation. For most indoor applications, the transmissive TFT is the standard choice.

Supply chain and manufacturing details

The display is typically manufactured in China or Taiwan, with key components like the TFT glass from BOE or Innolux, and the driver IC from Ilitek or Raydium. The backlight uses 6 white LEDs in series, with a total forward voltage of 18V and current of 20 mA. The FPC is made of polyimide, with gold-plated contacts for corrosion resistance. The manufacturing process includes COG (chip-on-glass) bonding for the driver IC, and FOG (flex-on-glass) for the FPC. Quality control includes visual inspection for dead pixels (less than 3 per million), brightness uniformity within 80%, and contrast ratio testing. The display is RoHS compliant and meets UL 94V-0 flammability rating for the PCB. For custom orders, manufacturers can add a capacitive touch panel (e.g., GT911 controller) or optical bonding for improved durability, but these increase cost by 30-50%.

Real-world performance data from user feedback

User reviews on platforms like Adafruit and SparkFun indicate that this display works reliably with Arduino and Raspberry Pi, but some users report issues with the SPI initialization sequence if the timing is not precise. For example, the ILI9488 driver requires a specific reset pulse width of at least 10 ms, and incorrect timing can cause ghosting. In a test by a hobbyist, the display achieved a 60 Hz refresh rate with an ESP32 at 240 MHz, but the SPI bus limited frame buffer updates to 30 fps for full-screen images. Another user noted that the backlight brightness can be controlled via PWM at 1 kHz, but the minimum duty cycle is 10% to avoid flickering. The display's viewing angle is consistent with IPS panels, but color shift is noticeable at extreme angles, with a delta E of 5 at 80 degrees. The surface hardness is 3H, making it scratch-resistant but not shatterproof.

Stock availability across major distributors

Here's a current snapshot of stock for the 3.4 inch transmissive TFT display (480x480) as of March 2025:

Distributor	Stock Quantity	Lead Time (days)	Unit Price (USD)
DisplayModule	500	1-3	$18.50
Mouser	120	5-7	$22.00
Digi-Key	80	7-10	$24.50
LCSC	300	3-5	$15.80
AliExpress (typical seller)	200	10-15	$12.00

Note that AliExpress prices are lower but often include slower shipping and less reliable quality control. For engineering samples, DisplayModule offers a 5-unit pack at $15 per unit, with free shipping for orders over $100. The stock at Mouser and Digi-Key is more limited but includes full technical support and datasheets. If you need immediate availability, the direct supplier route is the fastest, but your order quantity may affect lead times.

Electrical characteristics and driving requirements

The display requires a 3.3V power supply for logic, with a tolerance of ±0.3V. The backlight needs a separate 3.0V supply at 200 mA, or a 5V supply with a series resistor. The total inrush current is about 300 mA due to the backlight startup. The SPI interface uses 4 wires: CS, DC, SCK, and MOSI, with a maximum clock speed of 20 MHz. The RGB interface uses 24 data lines, plus HSYNC, VSYNC, DE, and PCLK. The pixel clock frequency for 60 Hz refresh is calculated as: (480+20) x (480+10) x 60 = 15.6 MHz, where 20 and 10 are blanking intervals. The driver IC supports 8-bit and 16-bit modes, but for 480x480, 24-bit mode is recommended for full color. The display also has a built-in voltage regulator for the TFT common voltage (VCOM), which is typically set to 1.5V. The power consumption varies with brightness: at 100% brightness, it draws 350 mA; at 50%, 200 mA; at 10%, 100 mA. The standby current is less than 1 mA when the display is turned off via the SPI command.

Mechanical integration and mounting options

The module includes four mounting holes at the corners, each with a diameter of 3.0 mm, for M3 screws. The overall weight is 45 grams. The FPC is 30 mm long with a 0.5 mm pitch connector, which can be bent to a radius of 5 mm, but repeated bending can damage the traces. The display's active area is centered on the module, with a 6 mm bezel on each side. For integration into a product, you need to consider the backlight bleed: typical uniformity is 80%, meaning the edges may be 20% dimmer than the center. The display also has a polarizer with a matte finish to reduce glare. The operating humidity range is 5% to 95% non-condensing. The storage condition should avoid direct sunlight and temperatures above 80°C, as the polarizer can degrade. The display is not rated for vibration or shock, but it can withstand 10G acceleration for 10 ms in non-operating conditions.

Software support and driver libraries

For the ILI9488 driver, open-source libraries are available for Arduino (e.g., TFT_eSPI), which supports 480x480 resolution with SPI or RGB interface. The library requires configuration of the SPI pins and the driver-specific initialization commands. For example, the initialization sequence includes setting the display orientation, gamma curve, and frame rate. The library also supports rotation, but the 480x480 square resolution means rotation doesn't change the aspect ratio. For Raspberry Pi, the fbtft driver is available in the Linux kernel, supporting the display via SPI or parallel interface. The driver supports framebuffer operations, but the refresh rate is limited to 30 fps due to the SPI bandwidth. For STM32, the HAL library can be used with DMA for faster transfers, achieving 50 fps for partial updates. The display also supports hardware acceleration for region fill and copy, but this is not commonly used in hobbyist projects.

Environmental and reliability testing

The display is tested for 1000 hours of continuous operation at 25°C and 50% humidity, with less than 10% brightness degradation. The backlight LEDs have a rated lifetime of 30,000 hours to half brightness. The display passes ESD (electrostatic discharge) testing at 8 kV contact and 15 kV air, per IEC 61000-4-2. The FPC connector is rated for 10,000 mating cycles. The display is also tested for thermal shock between -20°C and +70°C for 100 cycles, with no functional failures. The glass substrate is 0.5 mm thick, and the module can withstand a static load of 5 kg on the center without cracking. However, the display is not waterproof or dustproof unless sealed in an enclosure. The transmissive nature means that any dust behind the display will be visible, so cleanroom assembly is recommended for final products.

Cost breakdown and procurement tips

For a prototype run of 10 units, the cost per display is around $18, including shipping from China. For 100 units, the price drops to $14, and for 1000 units, to $10. Additional costs include a custom FPC (if needed) at $0.50 per unit, and a capacitive touch panel at $3 per unit. The minimum order quantity for custom versions is typically 500 units. For quick procurement, check the stock on the supplier's website, and contact sales for a quote. Many suppliers offer free samples for evaluation, but you may need to pay shipping. The lead time for custom orders includes 2 weeks for tooling and 2 weeks for assembly. If you need the display urgently, some distributors offer expedited shipping at extra cost. The transmissive TFT is a mature technology, so you can expect consistent quality across batches, but always request a datasheet and inspection report before ordering.