Product Main Title:
LS028T34-S-V1: 2.8-Inch TFT LCD Module, 240x320 Resolution, 262K Colors, 4-Line Serial Interface
Product Subtitle / Keywords:
2.8 Inch Display, QVGA 240x320 Resolution, Transmissive a-Si TFT, 4-Line Serial Interface (SPI), COG+FPC+B/L, 262K Colors, Standard Operating Temperature, RoHS Compliant
Comprehensive Technical Specification & Application Guide
1. Executive Summary & Product Positioning
The LS028T34-S-V1, developed by LESSON (Wan'an) Zhixian Technology Co., Ltd., is a standard 2.8-inch transmissive amorphous Silicon TFT-LCD module. This product specification book provides the definitive technical definition, covering its structural composition (COG+FPC+B/L), mechanical dimensions, absolute maximum ratings, detailed electrical characteristics, and 4-line serial interface (SPI) timing. It delivers a QVGA resolution of 240(RGB)×320 with 262K-color display capability. The document outlines the essential parameters for system integration and includes important mechanical design suggestions for housing integration. Engineers should use this document to guide the electrical connection, SPI communication, and mechanical mounting of the module, paying close attention to the recommended clearances for the bezel and foam gasket to ensure optimal display appearance and long-term reliability.
2. Detailed Product Overview & Architecture
- Core Technology: Transmissive-type a-Si TFT-LCD.
- Display Characteristics: Capable of displaying up to 262 thousand colors.
- Module Construction: COG (Chip-On-Glass) + FPC (Flexible Printed Circuit) + B/L (Backlight Unit). Composed of a TFT-LCD panel, a driver circuit, and a backlight unit.
- Interface: 4-line serial interface (SPI).
- Panel Size: 2.8 inch diagonal.
3. Exhaustive Technical Specifications
3.1 Mechanical & Physical Specifications
- Panel Size (Diagonal): 2.8 inches
- Active Area (H×V): 43.2 mm × 57.6 mm
- Module Size (H×V×D): 50.0 mm × 69.1 mm × 2.3 mm
- Resolution: 240 (RGB) × 320 pixels
- Number of Dots: 240(RGB) × 320
3.2 Electrical & Interface Specifications
3.2.1 Absolute Maximum Ratings
| Item | Symbol | Min | Max | Unit | Remark |
|---|---|---|---|---|---|
| Supply voltage | VCC | -0.3 | 4.6 | V | Note1,2 |
| I/O Supply voltage | IOVCC | -0.3 | 4.6 | V | Note1,2 |
| Operating temperature | TOPR | -10 | 60 | °C | Note1,2 |
| Storage temperature | TSTR | -20 | 70 | °C | Note1,2 |
3.2.2 Electrical Characteristics (DC)
| Item | Symbol | Min | Typ | Max | Unit |
|---|---|---|---|---|---|
| Supply voltage (Main) | VCC | 2.4 | 2.75 | 3.3 | V |
| I/O Supply voltage | IOVCC | 1.65 | 1.8 | 3.3 | V |
| Input Voltage (L) | VIL | 0 | -- | 0.3*IOVCC | V |
| Input Voltage (H) | VIH | 0.7*IOVCC | -- | IOVCC | V |
3.2.3 Pin Description (10-pin FPC)
| PIN NO. | Symbol | I/O | Description |
|---|---|---|---|
| 1 | GND | P | Ground |
| 2 | RS | I | Command and Data select pin (D/CX). |
| 3 | CS | I | Chip select pin. |
| 4 | SCL | I | Serial clock pin. |
| 5 | SDA | I/O | Serial data input/output pin. |
| 6 | RESET | I | Reset pin. |
| 7 | VCI | P | Power supply for analog circuits. |
| 8 | VSS | P | Ground. |
| 9 | LEDA | P | Power for LED backlight anode. |
| 10 | LEDK | P | Power for LED backlight cathode. |
3.2.4 4-Line Serial Interface Timing Characteristics
Conditions: VDDI=1.65-3.3V, VDD=2.4-3.3V, Ta=25°C.
The specification provides timing parameters for Serial clock cycle (T_SCYCR), SCL pulse widths (T_SHR, T_SLR), D/CX setup/hold (T_DCS, T_DCH), Data setup/hold (T_SDS, T_SDH), and Data access time (T_ACC). Note: In the provided excerpt, many values are listed as "TBD" (To Be Determined). The full document or manufacturer must be consulted for final numerical values.
3.2.5 Reset Timing:
| Related Pins | Symbol | Parameter | MIN | MAX | Unit | Note |
|---|---|---|---|---|---|---|
| RESX | TRW | Reset pulse duration | 10 | - | us | |
| RESX | TRT | Reset cancel time | - | 5 | ms | Note 1, 5 |
| RESX | TRT | Reset cancel time | - | 120 | ms | Note 1, 6, 7 |
The document includes a detailed spike rejection table: pulses shorter than 5µs are rejected; longer than 9µs cause a reset; between 5-9µs, a reset may start.
3.2.6 Backlight Unit
Information not explicitly detailed in provided excerpts, but typical for this size.
3.3 Optical & Electro-Optical Characteristics (Ta=25°C)
| Item | Symbol | Condition | Min. | Typ. | Max. | Unit | Remark |
|---|---|---|---|---|---|---|---|
| Response Time | Tr + Tf | θx=θy=0 | -- | 16 | 25 | ms | Note 1 |
| Contrast Ratio | CR | θx=θy=0 | 300 | 500 | -- | -- | Note 2 |
| Transmittance | T% | θx=θy=0 | 5.9 | 4.7 | -- | % | (Min/Typ seem swapped; confirm with full doc) |
| Viewing Angle (CR>10) | θT, θB | -- | 35 | 45 | -- | Deg. | Note 3 |
| Viewing Angle (CR>10) | θL | -- | 35 | 50 | -- | Deg. | Note 3 |
| Viewing Angle (CR>10) | θR | -- | 20 | 20 | -- | Deg. | Note 3 |
| Color Chromaticity (White) | W x, W y | θx=θy=0 | -- | 0.304, 0.344 | -- | -- | CIE1931 |
4. Application Guidelines & Critical Notes
- Intended Use: Industrial controls, consumer electronics, basic HMIs, educational kits—applications requiring a cost-effective, medium-sized color display with a simple SPI interface.
- Critical Design Considerations:
- Obtain Final Timing Values: The critical SPI timing parameters are listed as TBD. You must obtain the final specification sheet with filled-in min/max values from the supplier before finalizing your MCU's SPI configuration.
- Mechanical Integration Suggestions: The document emphasizes mechanical design for the end-product housing:
- Bezel Opening: Should be cut 0.3mm smaller per side than the module's active area (AA) to hide the non-display edges.
- Foam Gasket Cutout: Should be 0.6mm larger per side than the module's viewing area (VA) to avoid putting pressure on the display surface, which can cause Mura (cloudiness).
- Avoid Direct Pressure: No part of the housing should directly contact the polarizer surface.
- Standard SPI Interface: The 4-line interface (CS, SCL, SDA, D/CX) is compatible with most microcontroller SPI peripherals in 3-wire or 4-wire mode.
- Power Supply: Provide stable 2.75V (VCI) and 1.8V (IOVCC) supplies. Note the operating temperature range (-10°C to +60°C) is slightly narrower than some other models.
- Reset Spike Immunity: The built-in spike rejection on the RESET line (5-9µs window) helps prevent accidental resets from noise.
- Handling & Compliance: The module is ROHS compliant. Follow standard ESD precautions.
5. Conclusion & Design-In Support
The LS028T34-S-V1 specification outlines a reliable and widely-used 2.8-inch QVGA SPI display module. Its design is conventional, making it straightforward to integrate. The primary caution is that the key AC timing parameters are pending (TBD) in the provided excerpt, necessitating confirmation from the vendor. A significant value of this document is the clear mechanical integration guidance provided to preserve optical performance, which is often overlooked. By securing the final timing specs, providing clean power, and following the housing design rules to prevent pressure on the panel, this module can serve as a dependable visual interface for a multitude of embedded applications.
