LS0154I02-S-V2: 1.54-Inch a-Si TFT LCD Module, 240×240 Resolution, 262K Colors, SPI Interface

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Product Subtitle / Keywords:
1.54 Inch Display, 240(RGB)×240 Resolution, Transmissive a-Si TFT-LCD, SPI Interface, COG+FPC+B/L, 262K Colors, 30.52×33.72×1.95 mm, 250:1 Contrast Ratio, 5% Transmittance, 45°/20°/45°/45° Viewing Angle, -20°C~70°C Operating Temperature, 4-Line Serial Interface

1. Executive Summary & Product Positioning

The LS0154I02-S-V2, 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

表格
 
 
Item Specification Unit
Module size (H×V×D) 30.52 × 33.72 × 1.95 mm
Number of dots 240(RGB) × 240 pixel
Active area (H×V) 27.72 × 27.72 mm

3.2 Electrical & Interface Specifications

3.2.1 Absolute Maximum Ratings

表格
 
 
Item Symbol Min Max Unit Remark
Supply voltage VCC -0.3 4.6 V Note1 Note2
Supply voltage IOVCC -0.3 4.6 V Note1 Note2
Operating temperature TOPR -20 70 °C Note1 Note2
Storage temperature TSTR -30 80 °C Note1 Note2

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)

表格
 
 
Item Item Symbol Min Typ Max Unit
Supply voltage Supply voltage VCC 2.4 2.8 3.3 V
Supply voltage Supply voltage IOVCC 1.65 1.8 3.3 V
Input Voltage (L level) L level VIL 0 — 0.3*IOVCC V
Input Voltage (H level) H level VIH 0.7*IOVCC — IOVCC V

3.2.3 Pin Description (15-pin FPC)

表格
 
 
PIN NO. Symbol I/O Description
1 LEDK P Power for LED backlight cathode
2 GND GND P
3 TE O Tearing effect signal is used to synchronize MCU to frame memory
4 SDA I SPI interface input pin.
5 D/C O Display data/command selection pin in 4-line serial interface.
6 SCL I Serial clock pin
7 CS I Chip selection pin
8 RESET I This signal will reset the device and it must be applied to properly initialize the chip.
9 IOVCC P power supply
10 VCC P power supply
11 VCC P power supply
12 GND P Ground
13 GND P Ground
14 LEDA P Power for LED backlight anode
15 LEDA P Power for LED backlight anode

Interface Summary:

  • SPI Interface: Uses SCL (Serial Clock), SDA (Serial Data), D/C (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.

表格
 
 
Signal Symbol Parameter MIN MAX Unit Description
CSX
TCSST_{CSS}TCSS​
 Chip select setup time (write) TBD - ns  
CSX
TCSHT_{CSH}TCSH​
 Chip select hold time (write) TBD - ns  
CSX
TCSST_{CSS}TCSS​
 Chip select setup time (read) TBD - ns  
CSX
TSCCT_{SCC}TSCC​
 Chip select hold time (read) TBD - ns  
CSX
TCHWT_{CHW}TCHW​
 Chip select "H" pulse width TBD - ns  
SCL
TSCYCWT_{SCYCW}TSCYCW​
 Serial clock cycle (Write) TBD - ns -write command & data ram
SCL
TSHWT_{SHW}TSHW​
 SCL "H" pulse width (Write) TBD - ns -write command & data ram
SCL
TSLWT_{SLW}TSLW​
 SCL "L" pulse width (Write) TBD - ns -write command & data ram
SCL
TSCYCRT_{SCYCR}TSCYCR​
 Serial clock cycle (Read) TBD - ns -read command & data ram
SCL
TSHRT_{SHR}TSHR​
 SCL "H" pulse width (Read) TBD - ns  
SCL
TSLRT_{SLR}TSLR​
 SCL "L" pulse width (Read) TBD - ns  
D/CX
TDCST_{DCS}TDCS​
 D/CX setup time TBD - ns  
D/CX
TDCHT_{DCH}TDCH​
 D/CX hold time TBD - ns  
SDA (DIN)
TSDST_{SDS}TSDS​
 Data setup time TBD - ns  
SDA (DIN)
TSDHT_{SDH}TSDH​
 Data hold time TBD - ns  
DOUT
TACCT_{ACC}TACC​
 Access time TBD TBD ns For maximum CL=30pF For minimum CL=8pF
DOUT
TOHT_{OH}TOH​
 Output disable time TBD TBD ns For maximum CL=30pF For minimum CL=8pF

Important Note: All SPI timing parameters in this document revision are marked as "TBD" (To Be Determined). This indicates these values are pending final characterization by the manufacturer. Engineers should contact Lixin (Wan'an) Intelligent Display Technology Co., Ltd. directly for confirmed timing values before finalizing their design.

3.2.5 Backlight Unit

表格
 
 
Item Specification Unit
LED Circuit — (Backlight circuit diagram provided in document) —
Drive Condition IF = 60mA, Vf = 2.8 ~ 3.4V —

Backlight Circuit Diagram (from document):

 
 
LEDA → [Backlight Circuit] → LEDK
Drive Condition: IF = 60mA, Vf = 2.8 ~ 3.4V

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

表格
 
 
Item Item Symbol Condition Min. Typ. Max. Unit Remark
Response time Response time Tr + Tf θx = θy = 0 — 30 — ms Note 1
Contrast Ratio Contrast Ratio CR θx = θy = 0 — 250 — — Note 2
Transmittance Transmittance T% θx = θy = 0 4.5 5 — %  
Color Chromaticity (CIE1931) White W x θx = θy = 0 — 0.308 — —  
Color Chromaticity (CIE1931) White W y θx = θy = 0 — 0.325 — —  
Viewing angle θT   CR > 10 — 45 — Deg. Note 3
Viewing angle θB   CR > 10 — 20 — Deg. Note 3
Viewing angle θL   CR > 10 — 45 — Deg. Note 3
Viewing angle θR   CR > 10 — 45 — Deg. Note 3
Luminance (IF = 60mA) L   —   TBD   cd/m² Note 4

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:

  • θx = 0°, θy = 0° (Normal to LCD surface)
  • θy+ = 90° (12 o'clock direction, Top)
  • θx+ = 90° (3 o'clock direction, Right)
  • θx- = 90° (9 o'clock direction, Left)
  • θy- = 90° (6 o'clock direction, Bottom)
  • IC Bonding Pad location indicated on the diagram.

Note 4: Backlight Circuit

  • Circuit diagram: LEDA → [Backlight] → LEDK
  • Drive condition: IF = 60mA, Vf = 2.8 ~ 3.4V

Note 5: Optical Characteristic Measurement Setup
The optical measurement setup diagram shows:

  • Photo-detector (BM-5A, Field=2°)
  • Distance: 50cm from LCD panel surface
  • Measurement angle: Normal to LCD surface

3.4 Version Record

表格
 
 
Version Date Page Content
1.0 — — First issue

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

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, SDA, D/C, 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 60 mA at 2.8~3.4V.

  3. Interface Timing Requirements:

    • All SPI timing parameters in this document are marked as "TBD". Contact Lixin (Wan'an) Intelligent Display Technology Co., Ltd. for confirmed timing values.
    • The serial interface uses a 4-line serial configuration with D/C (Data/Command), CS (Chip Select), SCL (Serial Clock), and SDA (Serial Data) signals.

  4. Mechanical Integration:

    • Module Outline: 30.52mm (H) × 33.72mm (V) × 1.95mm (D).
    • Active Area: 27.72mm × 27.72mm – a perfectly square display.
    • FPC: The module uses a 15-pin FPC for connection.

  5. Viewing Angle Characteristics:
    This module has the following viewing angle performance (CR > 10):

    • Top (12 o'clock): 45° (Typ)
    • Bottom (6 o'clock): 20° (Typ)
    • Left (9 o'clock): 45° (Typ)
    • Right (3 o'clock): 45° (Typ)

    Important Note: The viewing angle is asymmetric – the bottom direction (6 o'clock) has a significantly narrower viewing angle (20°) compared to the other directions (45°). This should be carefully considered in the mechanical design. The best image quality is obtained when viewing from the top (12 o'clock) direction.

  6. Optical Performance:

    • Response Time: 30ms (Typ) – suitable for most GUI applications.
    • Contrast Ratio: 250 (Typ) – moderate contrast performance.
    • Transmittance: 4.5% (Min), 5% (Typ).
    • White Chromaticity (CIE1931): Wx = 0.308, Wy = 0.325 (Typical).
    • Luminance: Marked as TBD – contact manufacturer for confirmed value.

  7. Temperature Limits:

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

Handling & Compliance

  • Observe standard ESD precautions during handling and assembly.
  • The module contains fragile glass and a 15-pin FPC – handle with care.
  • The module is 1.95mm thick – be careful when handling to avoid flexing.

5. Conclusion & Design-In Support

The LS0154I02-S-V2 specification details a compact 1.54-inch a-Si TFT-LCD display module with an SPI interface — a suitable choice for compact display applications requiring a square format.

Key Strengths:

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

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

  3. Compact Size: 30.52mm × 33.72mm × 1.95mm – suitable for space-constrained applications.

  4. Fast Response Time: 30ms (Typ) – adequate for most GUI applications.

  5. Good Transmittance: 5% (Typ) – allows for efficient backlight usage.

Main Design Focus:

  • The critical design task is contacting the manufacturer for confirmed SPI timing values, as all timing parameters are marked as "TBD" in this document revision.
  • Supporting requirements:
    • Provide stable VCC (2.8V typical) and IOVCC (1.8V typical) power.
    • Provide a constant-current backlight driver set to 60 mA at 2.8~3.4V.
    • Mechanical integration — account for the asymmetric viewing angle (20° bottom direction).
    • FPC connector — verify the 15-pin FPC pin count and pitch from the mechanical drawing.

This module is a suitable choice for compact display applications requiring a square 1.54-inch display with an SPI interface, though the asymmetric viewing angle (20° bottom direction) should be carefully considered in the mechanical design.