Product Subtitle / Keywords:
1.99 Inch Display, 400(RGB)×454 Resolution, Transmissive a-Si TFT-LCD, SPI Interface, COG+FPC+B/L, 262K Colors, 35.82×42.48×1.6 mm, 900:1 Contrast Ratio, 25ms Response Time, 250 cd/m² Luminance, ALL O’Clock Viewing Direction, -20°C~60°C Operating Temperature

1. Executive Summary & Product Positioning

The LS0200I04-SP-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 1.99-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 SPI (Serial Peripheral Interface) pinout and timing, and comprehensive electro-optical performance. It delivers a resolution of 400(RGB)×454 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: 1.99 inch.
• Resolution: 400(RGB)*454.
• Display Colors: Up to 262k colors.
• Viewing Direction: ALL O’Clock.
• Approval Status: ☑ Approved Product Specification only (as per signature block).

3. Exhaustive Technical Specifications

3.1 Mechanical & Physical Specifications

Critical Mechanical Design Notes (from outline dimension drawing):

1. Display Mode: 1.99” IPS.
2. Resolution: 400(RGB) X 454 DOTS.
3. Viewing Angle: ALL O’Clock.
4. Glass Model & Supplier: HSD.
5. Operating Temperature: -20°C TO 60°C.
6. Storage Temperature: -30°C TO 70°C.
7. General Tolerance: ±0.2 mm (unmarked).
8. Dimensions with * are critical dimensions.
9. ROHS Compliance: Yes.
10. Backlight Circuit: White LED (3.1V 60mA, 3LED).
11. Interface Mode: SPI.
12. Connector: OK-14GM024-04.
13. FPC Bend: The FPC is shipped in a bent configuration (FPC弯折出货).
14. Steel Plate Reinforcement: SUS201, T=0.1mm.
15. Conductive Adhesive: T=0.1mm.
16. Bezel Opening Design: It is recommended that the housing’s visible area (VA) be at least 0.3mm larger per side than the module’s active area (AA).
17. Backlight Circuit Diagram: Provided in the drawing.
18. Average Luminance: 330 cd/m² (typ).
19. Chromaticity: Center point chromaticity with a tolerance of ±0.03 from the signed sample center value.

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)

A. LCM Electrical Characteristics:

B. Backlight Characteristics:

3.2.3 Pin Description (24-pin FPC)

Interface Summary:

• SPI Interface: Uses SPI-SCL (Serial Clock), SPI-SDA (Serial Data), SPI-DCX (Data/Command), SPI-CS (Chip Select), and LCD_RST_N (Reset) for communication.
• TE Pin (Pin 21): Tearing effect output — can be used for frame synchronization.
• Backlight: Dedicated LED_A (Anode, Pin 8) and LED_K (Cathode, Pin 9) pins.
• Power: VDD(2.8V) (Pin 7) for main logic, VDDIO_1.8V (Pins 13, 14) for I/O interface, GND (Pins 6, 12, 15, 22, 23) for ground.
• Touch Panel Interface: Pins 1-5 provide a dedicated interface for an external capacitive touch panel (TP VDD2V8, TP_INT, TP_SDA, TP_SCL, TP_RSTN).

3.2.4 Reset Characteristics

Reset Timing Notes (from document):

• Power On Reset: The RESET_N pin must be held low for at least 1ms after power supplies (VDDIO, VCI) are stable.
• Operation Reset: During normal operation, the RESET_N pin must be held low for at least 500μs to initiate a reset.
• Reset Time: After releasing the reset pin, the device requires 20ms to complete the initialization sequence.
• Spike Rejection: A reset pulse shorter than 5μs will be rejected.

3.2.5 Power On/Off Sequence

The document provides a Power On/Off Sequence diagram (Figure 14-1) with the following key timing requirements:

• Power On Sequence:

  1. Apply VDDIO first.
  2. After >1ms, apply VCI.
  3. After >1ms, release RESX (set to high).
  4. After 210μs, send initialization commands.
  5. After 120ms, send Sleep Out command.
  6. After 120ms, send Display On command.

• Power Off Sequence:

  1. Send Display Off command.
  2. Send Sleep In command.
  3. Wait 120ms.
  4. Set RESX low.
  5. Remove VCI.
  6. After >1ms, remove VDDIO.

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%
• Tr (Rise Time): Time from 10% to 90% of optical response.
• Tf (Fall Time): Time from 90% to 10% of optical response.
• Tr + Tf = Total Response Time.

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 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.

Note 4: Backlight Circuit

• Drive condition: IF = 60mA, Vf = 3.1V (from outline dimension).

3.4 Version Record

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 display with excellent 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 (SPI-SCL, SPI-SDA, SPI-DCX, SPI-CS, LCD_RST_N) to drive the display.

2. Power Supply:

   • Provide stable VDD (2.5V to 3.3V, 2.8V typical) for the main logic (connected to Pin 7).
   • Provide stable VDDIO (1.65V to 3.3V, 1.8V typical) for the I/O interface (connected to Pins 13, 14).
   • The backlight requires a constant-current LED driver connected to LED_A (Anode, Pin 8) and LED_K (Cathode, Pin 9), set to 60 mA at approximately 3.0V (Typ).

3. Touch Panel Interface:

   • The module includes a dedicated TP interface (Pins 1-5) for an external capacitive touch panel.
   • The TP interface uses: TP_SCL (I²C clock), TP_SDA (I²C data), TP_RSTN (Reset), TP_INT (Interrupt), and TP VDD2V8 (Power).
   • Ensure the touch panel controller is properly initialized via its I²C interface.

4. Reset Circuit:

   • The LCD_RST_N pin (Pin 16) is active low.
   • Power On Reset: It must be driven low for at least 1ms after power supplies are stable.
   • Operation Reset: It must be driven low for at least 500μs during normal operation.
   • After releasing RESET, wait 20ms before sending any commands.
   • A pulse shorter than 5μs will be rejected.
   • A simple RC circuit (10kΩ resistor to VCC, 1μF capacitor to GND) or an MCU GPIO is recommended.

5. Power On/Off Sequence:

   • Power On: VDDIO → VCI → RESX → Commands → Sleep Out → Display On.
   • Power Off: Display Off → Sleep In → RESX → VCI → VDDIO.
   • Strictly follow the timing requirements to prevent damage to the module.

6. TE (Tearing Effect) Pin (Pin 21):

   • The TE pin outputs the display’s tearing effect signal.
   • This signal can be used to synchronize MCU frame writes with the display’s internal refresh cycle, preventing screen tearing.
   • If not used, leave this pin open.

7. Mechanical Integration:

   • Module Outline: 35.82mm (H) × 42.48mm (V) × 1.6mm (D).
   • Active Area: 33.42mm × 37.93mm.
   • FPC: The module uses a 24-pin FPC.
   • Steel Plate Reinforcement: The module includes a 0.2mm steel plate (SUS201) on the back for structural integrity.
   • Bezel Opening: Design the housing window 0.3mm larger per side than the active area.
   • FPC Bend: The FPC is shipped in a specific bent configuration — verify the bend direction matches your mechanical design.

8. Viewing Angle Characteristics:
   This is an IPS panel with excellent viewing angle performance (CR > 10):

   • Top (12 o'clock): 80° (Typ)
   • Bottom (6 o'clock): 80° (Typ)
   • Left (9 o'clock): 80° (Typ)
   • Right (3 o'clock): 80° (Typ)

   The module provides near-perfect viewing angles in all directions, making it ideal for wearable devices.

9. Optical Performance:

   • Response Time: 25ms (Typ) – fast enough for most GUI applications.
   • Contrast Ratio: 800 (Min), 900 (Typ) – excellent contrast performance for an IPS panel.
   • Luminance (IF = 60mA): 200 cd/m² (Min), 250 cd/m² (Typ).
   • Average Luminance (from drawing): 330 cd/m² (typ).

10. Temperature Limits:

    • Operating Temperature: -20°C to +60°C.
    • Storage Temperature: -30°C to +70°C.

Handling & Compliance

• The module is ROHS compliant.
• Observe standard ESD precautions during handling and assembly.
• The module contains fragile glass and a 24-pin FPC – handle with care.
• Avoid bending the FPC sharply, especially near the connector interface.
• The module has a total thickness of 1.6mm – be careful when handling to avoid flexing.
• The module includes a steel plate reinforcement on the back for structural integrity.

5. Conclusion & Design-In Support

The LS0200I04-SP-V1 specification details a high-performance 1.99-inch IPS display module with an SPI interface — an excellent choice for wearable and compact display applications requiring high resolution, excellent image quality, and wide viewing angles.

Key Strengths:

1. High Resolution: The 400×454 resolution in a 1.99-inch format provides excellent pixel density for sharp text and graphics.

2. Excellent IPS Technology: 80° viewing angles in all directions ensure consistent image quality from any perspective — essential for wearable devices.

3. Integrated Touch Panel Interface: The dedicated TP interface (Pins 1-5) simplifies integration with external capacitive touch panels.

4. Excellent Contrast Ratio: 900:1 (Typ) provides outstanding image quality for an IPS panel.

5. Fast Response Time: 25ms (Typ) – suitable for most GUI applications.

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

7. Comprehensive Power Sequencing Documentation: Detailed power on/off sequence timing ensures reliable operation.

Main Design Focus:

• The critical design task is properly implementing the SPI interface and strictly following the power on/off sequence to ensure reliable operation.
• Supporting requirements:
  • Provide stable VDD (2.8V typical) and VDDIO (1.8V typical) power.
  • Provide a constant-current backlight driver set to 60 mA at 3.0V (Typ).
  • Mechanical integration — the module outline is 35.82mm × 42.48mm × 1.6mm.
  • FPC connector — verify the 24-pin FPC.
  • Touch panel integration — connect and initialize the external touch panel via the dedicated TP interface.
  • Reset timing — ensure proper reset pulse width (≥1ms for power on, ≥500μs for operation) and wait times (20ms after reset).
  • Power sequencing — strictly follow the VDDIO → VCI → RESX sequence for power on and the reverse for power off.

This module is an excellent choice for high-end wearable devices, smartwatches, and any compact IoT application requiring a high-resolution IPS display with excellent viewing angles and integrated touch panel support.