Product Subtitle / Keywords:
1.54 Inch Display, 240(RGB)×240 Resolution, Transmissive a-Si TFT-LCD, SPI Interface, COG+FPC+B/L, 262K Colors, 2.4V~3.3V VCC, 1.65V~3.3V IOVCC, -20°C~70°C Operating Temperature, -30°C~80°C Storage Temperature, 4-Line Serial Interface

1. Executive Summary & Product Positioning

The LS0154I04-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 1.54-inch transmissive amorphous Silicon TFT-LCD (a-Si TFT-LCD) module.

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 4-line Serial Interface (SPI) pinout and timing, and comprehensive electro-optical performance. It delivers a square resolution of 240(RGB)×240 with 262K-color display capability.

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).
• 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.
• Panel Size: 1.54 inch.
• Resolution: 240(RGB)*240.
• Display Colors: Up to 262k colors.
• Approval Status: ☑ Approved Product Specification only (as per signature block).

3. Exhaustive Technical Specifications

3.1 Mechanical & Physical Specifications

The mechanical drawing provides the following key dimensions and notes:

Critical Mechanical Design Notes (from document):

1. Display Type: TFT 1.54", IPS, 240*240.
2. Viewing Direction: IPS.
3. Polarizer: Upper matte 7° / Lower gloss 90°.
4. Backlight: 3 Chip-White LED, Parallel.
5. Driver IC: ST77916.
6. Interface: 4-line SPI, 1 channel.
7. Operating Temperature: -20°C ~ +70°C.
8. Storage Temperature: -30°C ~ +80°C.
9. ROHS Compliance: Yes.
10. General Tolerance: ±0.20 mm (unmarked).
11. Angular Tolerance: ∠ ±1/4°.
12. FPC Pitch: 0.5mm.
13. FPC Bend: FPC is shipped in a bent configuration (FPC弯折示意图).
14. Backlight Drive Condition: IF = 45~75mA, Vf = 3V (TYP).
15. Dimensions marked with * are critical dimensions; dimensions in () are reference dimensions.
16. Bezel Opening Design: It is recommended that the housing's visible area be at least 0.3mm smaller per side than the module's viewing area (VAmds).
17. Foam Gasket Cutout Design: The cutout in the chassis foam gasket should be at least 0.6mm larger per side than the module's viewing area (VAmds).
18. TP/Conductor Isolation: The Touch Panel (TP) edges must not come into contact with any metal conductors.
19. Flatness: Overall flatness ≤ 0.35mm.
20. LCD Cutting Edge Chipping: ≤ 1/3 of single layer LCD thickness.

3.2 Electrical & Interface Specifications

3.2.1 Absolute Maximum Ratings

(Not explicitly provided in the extracted document excerpt; refer to Section 5 of the full specification.)

3.2.2 Electrical Characteristics (DC – Recommended Operating Conditions)

3.2.3 Pin Description (15-pin FPC)

Interface Summary:

• SPI Interface: Uses SCL (Serial Clock), SDA (Serial Data), RS (Data/Command), CS (Chip Select), and RESET for communication.
• TE Pin (Pin 3): Tearing effect output — can be used for frame synchronization.
• Backlight: Dedicated LEDA (Anode, Pins 14, 15) and LEDK (Cathode, Pin 1) pins.
• Power: VCC (Pins 10, 11) for main logic, IOVCC (Pin 9) for I/O interface, GND (Pins 2, 12, 13) for ground.

3.2.4 Serial Interface Timing Characteristics (4-line serial)

Conditions: VDDI=1.65 to 3.3V, VDD=2.4 to 3.3V, AGND=DGND=0V, Ta=25°C.

(The specific timing parameter values for this model are referenced in the document's section 7-3 Timing Characteristics and 7.4.3 Serial Interface Characteristics, but the exact numerical values are not fully extracted from the provided context excerpt.)

The timing diagram (Figure 5) shows the following signal relationships:

• CSX: Chip select signal.
• SCL: Serial clock signal.
• SDA: Serial data input/output.
• D/CX: Data/Command selection.
• DOUT: Data output.

The timing diagram illustrates the setup and hold times for CSX, SCL, SDA, and D/CX signals during both write and read operations.

3.2.5 Backlight Unit

3.3 Optical & Electro-Optical Characteristics

(Not explicitly provided in the extracted document excerpt; refer to Section 8 of the full specification.)

3.4 Version Record

(Not explicitly provided in the extracted document excerpt; refer to Section 9 of the full specification.)

4. Application Guidelines & Critical Notes

Intended Use

• Smartwatches, fitness trackers, and other wearable devices
• IoT display nodes and smart home controls
• Miniature handheld instruments
• Any application requiring a compact, high-resolution square display with IPS viewing angles

Critical Design Considerations

1. Interface (SPI): This module uses an SPI (Serial Peripheral Interface) for communication. The host MCU must have at least 5 GPIOs (SCL, SDA, RS, CS, RESET) to drive the display.

2. Power Supply:

   • Provide stable VCC (2.8V 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 45~75 mA at 3V (TYP).

3. Interface Timing Requirements:

   • The serial interface uses a 4-line serial configuration with RS (Data/Command), CS (Chip Select), SCL (Serial Clock), and SDA (Serial Data) signals.
   • The timing diagram (Figure 5) provides the signal relationships for proper operation.

4. Mechanical Integration:

   • Module Size: The outline drawing shows precise dimensions for the module. Key dimensions include:
     • LCD AA (Active Area): 27.72mm.
     • LCD & CF: 30.32mm.
     • POL: 29.92mm.
     • BL: 31.52mm.
   • FPC: The module uses a 15-pin FPC with 0.5mm pitch.
   • FPC Bend: The FPC is shipped in a specific bent configuration (FPC弯折示意图) — verify the bend direction matches your mechanical design.
   • Bezel Opening: Design the housing window 0.3mm smaller per side than the viewing area.
   • Foam Gasket: Design the cutout 0.6mm larger per side than the viewing area.
   • Flatness: Overall module flatness must be ≤ 0.35mm.
   • LCD Cutting Edge Chipping: Must be ≤ 1/3 of single layer LCD thickness.

5. Viewing Angle Characteristics:
   This is an IPS panel providing wide viewing angles in all directions.

6. Temperature Limits:

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

7. Backlight Drive:

   • The backlight consists of 3 Chip-White LEDs in parallel.
   • The drive condition is IF = 45~75mA, Vf = 3V (TYP).
   • Use a constant-current LED driver set to the appropriate current within the 45~75mA range.

Handling & Compliance

• The module is ROHS compliant.
• Observe standard ESD precautions during handling and assembly.
• The module contains fragile glass and a 15-pin FPC – handle with care.
• The module includes a single-layer bending zone on the FPC — avoid sharp bending at other locations.
• The module has a yellow insulation paper (黄色绝缘胶纸) for handling during assembly.

5. Conclusion & Design-In Support

The LS0154I04-S-V1 specification details a compact 1.54-inch IPS display module with an SPI interface — an excellent choice for compact display applications requiring a square format with wide viewing angles.

Key Strengths:

1. IPS Technology: Provides wide viewing angles in all directions.

2. Square Resolution (240×240): Suitable for round or circular watch face UIs (with circular masking) or symmetrical UI designs.

3. Standard SPI Interface: Requires only 5 GPIOs for communication, simplifying integration.

4. Compact Size: The module is designed for space-constrained applications.

5. Wide Operating Temperature Range: -20°C to +70°C for operation and -30°C to +80°C for storage.

6. TE (Tearing Effect) Support: The dedicated TE pin enables tear-free graphics synchronization.

Main Design Focus:

• The critical design task is properly implementing the SPI interface and ensuring the backlight driver is set to the correct current (45~75mA).
• Supporting requirements:
  • Provide stable VCC (2.8V typical) and IOVCC (1.8V typical) power.
  • Provide a constant-current backlight driver set to 45~75 mA at 3V (TYP).
  • Mechanical integration — follow the bezel opening and foam cutout guidelines.
  • FPC connector — verify the 15-pin FPC with 0.5mm pitch.
  • FPC bend direction — verify the bend direction matches your mechanical design.

This module is an excellent choice for compact display applications requiring a square 1.54-inch IPS display with an SPI interface, wide viewing angles, and a wide operating temperature range.