Product Subtitle / Keywords:
1.44 Inch Display, 128(RGB)×128 Resolution, Transmissive a-Si TN TFT, 3-Line/4-Line SPI Serial Interface, COG+FPC+B/L, 262K Colors, ST7735S Driver, 2.5mm Thickness, 300:1 Contrast Ratio, -20°C~70°C Operating Temperature

1. Executive Summary & Product Positioning

The LS0144T05-S-V1, developed by Lixin (Wan'an) Intelligent Display Technology Co., Ltd. (立信(万安)智显科技有限公司), is a 1.44-inch transmissive amorphous Silicon TFT-LCD module with TN (Twisted Nematic) technology.

This product specification (Revision 1.0, Module Type: COG+FPC+B/L) serves as the definitive technical document, defining its structural composition (COG+FPC+B/L), physical features, mechanical dimensions, absolute maximum ratings, detailed electrical characteristics, complete 3-line and 4-line Serial SPI Interface pinout and timing, and comprehensive electro-optical performance. It delivers a QQVGA resolution of 128(RGB)×128 with 262K-color display capability, driven by the ST7735S controller.

The document provides the core parameters necessary for system integration into compact embedded display applications. The unequivocal recommendation for engineers is to strictly adhere to the electrical specifications, interface timing, and mechanical tolerances described herein to ensure reliable performance and compatibility.

2. Detailed Product Overview & Architecture

• Core Technology: Transmissive-type a-Si TFT-LCD (amorphous silicon thin film transistor liquid crystal display).
• Display Mode: Active matrix TFT, Transmissive type, TN.
• 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.
• Input Data: 3-Line Serial Interface & 4-Line Serial Interface (selectable).
• Viewing Direction (Grayscale Inversion): 12 o'clock (as per the drawing marking).
• Drive IC: ST7735S.
• Approval Status: ☑ Approved Product Specification only (as per signature block).

3. Exhaustive Technical Specifications

3.1 Mechanical & Physical Specifications

Critical Mechanical Design Notes (from document):

1. Display Type: TFT, TN, Transmissive.
2. Operating Temperature: -20°C ~ +70°C.
3. Storage Temperature: -30°C ~ +80°C.
4. Supply Voltage VDD: 2.8V ~ 3.3V.
5. Viewing Direction: 12 o'clock.
6. Interface: SPI.
7. Drive IC: ST7735S.
8. Polarizer: Normal white TFT (BOE).
9. Backlight: 1 LED (as per the circuit diagram).
10. CA Thickness (PI+FPC): 0.30mm.
11. Customer Part: LUOLFLUOLF.
12. General Tolerance:
    • Decimal dimension: ±0.20 mm.
    • Two decimal dimension: ±0.10 mm.
    • Angular dimension: ±1/4°.
13. Pitch: 0.5mm × 9 pins = 4.50 ± 0.05mm.
14. Output Status: Not in scale.
15. Unit: mm.

3.2 Electrical & Interface Specifications

3.2.1 Absolute Maximum Ratings

Notes (interpreted):

• Note1/Note2: Stress beyond these ratings may cause permanent damage; functional operation is not implied under these conditions.

3.2.2 Electrical Characteristics (DC – Recommended Operating Conditions)

3.2.3 Pin Description (from mechanical drawing)

The mechanical drawing provides the following pin assignments for the interface. The drawing indicates a 10-pin electrical interface with the following definition:

Interface Summary:

• 3-Line & 4-Line SPI Interface: Supports both interface modes using SCL (Serial Clock), SDA (Serial Data), RS (Register Select for 4-line), RES (Reset), and EC (Chip Select).
• Backlight: Dedicated LED- (Pin 7) for cathode and a separate LED+ annotation for anode.
• Power: VDD (Pin 2) for main logic, GND (Pin 10) for ground.

3.2.4 Serial Interface Timing Characteristics

Conditions: Ta=25°C, VDDI=1.65~3.7V, VDD=2.5~3.7V.

A. 3-Line Serial Interface Timing:

B. 4-Line Serial Interface Timing:

Key Timing Observations:

• Write timing is faster than read timing: Write clock cycle (TSCYCW) is 20ns (50 MHz), while read clock cycle (TSCYCR) is 150ns (6.67 MHz).
• Data setup/hold time: TSDS = TSDH = 10ns – consistent between both 3-line and 4-line modes.
• Chip select hold time: TCHW = 40ns minimum.

3.2.5 Backlight Unit

3.3 Optical & Electro-Optical Characteristics (Ta=25°C)

Notes (from document):

Note 1: Definition of Response Time
The response time is defined as the following figure and shall be measured by switching the input signal for "black" and "white". This definition is valid for a normally black display. For a normally white display the opposite definition applies.

The response time definition diagram shows:

• Optical Response (%): Black = 0%, White = 100%
• T_ON (Rise Time): Time from 10% to 90% of optical response.
• T_OFF (Fall Time): Time from 90% to 10% of optical response.
• Tr + Tf = T_ON + T_OFF.

Note 2: Definition of Contrast Ratio
Contrast ratio (CR) is defined mathematically by the following formula:
Contrast Ratio = Luminance measured when LCD on the "White" state / Luminance measured when LCD on the "Black" state

Note 3: Definition of Viewing Angle
Viewing angle is the angle at which the contrast ratio is greater than 10. Angles are determined for the horizontal or x axis and the vertical or y axis with respect to the z axis which is normal to the LCD surface.

The viewing angle definition diagram shows:

• θ = 0° (z-axis, normal to LCD surface)
• Φ = 0° (3 o'clock direction, Right)
• Φ = 90° (12 o'clock direction, Top/Up)
• Φ = 180° (9 o'clock direction, Left)
• Φ = 270° (6 o'clock direction, Bottom/Down)

Note 4: Backlight Circuit

• Circuit diagram: LED+ (Anode) → 1O → LED- (Cathode)
• Drive condition: IF = 40mA, VF = 2.7 ~ 3.3V (Typical)

4. Application Guidelines & Critical Notes

Intended Use

• Low-cost IoT devices
• Simple user interfaces requiring compact size
• Applications where resolution requirements are modest (128x128)
• Wearable devices, smart home controls, miniature instruments

Critical Design Considerations

1. Interface (3-Line & 4-Line SPI): This module supports both 3-line serial and 4-line serial SPI interfaces. The host MCU must have at least 4 to 5 GPIOs depending on the interface mode selected.

2. Power Supply:

   • Provide stable VCC (2.75V typical) for the main logic.
   • Provide stable IOVCC (1.8V typical) for the I/O interface.
   • The backlight requires a constant-current LED driver set to 40 mA at 2.7~3.3V.

3. Interface Timing Requirements:

   • For write operations, the serial clock cycle (TSCYCW) must be ≥ 20ns (50 MHz maximum). This is a fast write speed requiring careful PCB layout.
   • For read operations, the serial clock cycle (TSCYCR) must be ≥ 150ns (6.67 MHz maximum).
   • Data setup time (TSDS) and data hold time (TSDH) must be ≥ 10ns.
   • Chip select setup time (TCSS): 15ns for write, 60ns for read.

4. Mechanical Integration:

   • Module Outline: 29.5mm (H) × 36.5mm (V) × 2.5mm (D).
   • Active Area: 25.5mm × 26.5mm.
   • FPC: The module uses a 10-pin FPC with 0.5mm pitch (9 pins × 0.5mm = 4.50mm total width).
   • CA Thickness (PI+FPC): 0.30mm.

5. Temperature Limits:

   • Operating Temperature: -20°C to +70°C.
   • Storage Temperature: -30°C to +80°C.

6. Viewing Direction: This is a 12 o'clock TN panel with asymmetric viewing angles:

   • Top (12 o'clock): 70° (Typ)
   • Bottom (6 o'clock): 60° (Typ)
   • Left (9 o'clock): 75° (Typ)
   • Right (3 o'clock): 75° (Typ)

   Best image quality is obtained when viewing from the 12 o'clock direction (top).

7. Optical Performance:

   • Response Time: 25ms (Typ), 30ms (Max) – fast enough for most simple GUI applications.
   • Contrast Ratio: 300 (Min), 600 (Typ) – adequate for indoor use.
   • Transmittance: 3.9% (Min), 5.5% (Typ).
   • White Chromaticity (CIE1931): Wx = 0.301, Wy = 0.327 (Typical).

Handling & Compliance

• The module is ROHS compliant.
• Observe standard ESD precautions during handling and assembly.
• The module contains fragile glass and a 10-pin FPC – handle with care.
• The module is 2.5mm thick – be careful when handling to avoid flexing.
• The module includes a LUOLFLUOLF customer part number marking.

5. Conclusion & Design-In Support

The LS0144T05-S-V1 specification details a compact 1.44-inch TN display module with a flexible 3-line/4-line SPI interface — an excellent choice for cost-sensitive, simple display applications.

Key Strengths:

1. Compact Size: 29.5mm × 36.5mm — one of the smallest modules in the product line.
2. Square Resolution (128x128): Suitable for simple icons, text, and basic UIs.
3. Flexible SPI Interface: Supports both 3-line and 4-line serial interfaces, providing connection flexibility.
4. Fast Write Speed: 20ns write cycle (50 MHz) allows for rapid screen updates.
5. Adequate Brightness: The backlight drive is 40mA at 2.7~3.3V, providing sufficient brightness for indoor use.
6. Good Contrast Ratio: 600:1 (Typ) provides decent image quality for a TN panel.
7. Comprehensive Timing Documentation: Detailed serial interface timing parameters provided for both 3-line and 4-line modes.

Main Design Focus:

• The critical design task is properly implementing the SPI interface timing, especially the 20ns write cycle requirement which demands careful PCB layout with short trace lengths.
• Supporting requirements:
  • Provide stable VCC (2.75V typical) and IOVCC (1.8V typical) power.
  • Provide a constant-current backlight driver set to 40 mA at 2.7~3.3V.
  • Mechanical integration — the module outline is 29.5mm × 36.5mm × 2.5mm.
  • FPC connector — verify the 10-pin FPC with 0.5mm pitch.

Comparison with Related Models:

Key Differences from Related Models:

• The LS0144T05-S-V1 has a larger module outline (29.5 × 36.5 mm) compared to the T03 and T04 models (27.9 × 32.64 mm).
• It is thicker (2.5mm) compared to the T03 and T04 models (2.1mm).
• It offers wider viewing angles (70°/60°/75°/75°) compared to the 60° uniform viewing angles of the T03 and T04 models.
• It uses a single LED backlight (1 LED) compared to the 2 LED backlights of the T03 and T04 models.
• It has a 10-pin FPC compared to the 12-pin (T03) and 15-pin (T04) FPCs.
• The response time is faster (25ms Typ) compared to the 32ms Max of the T03 and T04 models.
• The operating temperature range is wider (-20°C to +70°C) compared to the T03 model (-10°C to +60°C).
• This module supports both 3-line and 4-line SPI interfaces, offering more connection flexibility.

This module is an excellent choice for designs where cost, size, and simplicity are the primary concerns, such as simple numeric displays, status indicators, or low-cost IoT nodes, with the added benefit of wider viewing angles and faster response time compared to its siblings.