LTD-2601JG-J LED Display Datasheet - 0.28-inch Digit Height - AlInGaP Green - 2.6V Forward Voltage - 70mW Power Dissipation - English Technical Document

1. Product Overview

The LTD-2601JG-J is a dual-digit, seven-segment alphanumeric display module designed for clear numeric readouts in various electronic applications. It features a digit height of 0.28 inches (7.0 mm), providing a balance between compact size and good visibility. The device utilizes AlInGaP (Aluminum Indium Gallium Phosphide) semiconductor technology for its green light-emitting segments, offering high brightness and efficiency. The display has a gray face with white segments, enhancing contrast and readability. Its primary advantages include low power consumption, excellent character appearance with continuous uniform segments, high brightness, wide viewing angles, and solid-state reliability. It is categorized for luminous intensity and comes in a lead-free package compliant with RoHS directives.

2. Technical Parameters Deep Dive

2.1 Electrical & Optical Characteristics

The device's performance is specified at an ambient temperature (Ta) of 25°C. Key parameters include:

• Average Luminous Intensity per Segment: Ranges from a minimum of 200 ucd to a maximum of 3400 ucd, with a typical value of 540 ucd, measured at a forward current (IF) of 1 mA.
• Average Luminous Intensity per Decimal Point (DP): Minimum of 50 ucd at IF=1mA.
• Peak Emission Wavelength (λp): 571 nm at IF=20mA.
• Dominant Wavelength (λd): 572 nm at IF=20mA.
• Spectral Line Half-Width (Δλ): 15 nm at IF=20mA.
• Forward Voltage per Segment (VF): Typically 2.6V, with a maximum of 2.6V at IF=20mA.
• Reverse Current per Segment (IR): Maximum of 100 µA at a reverse voltage (VR) of 5V. Note that this is a test condition and the device is not intended for continuous reverse bias operation.
• Luminous Intensity Matching Ratio: 2:1 maximum for similar light areas at IF=1mA.
• Dominant Wavelength Matching Delta (Δλd): 4 nm maximum for similar light areas at IF=20mA.
• Crosstalk: Specified to be ≤ 2.5%.

2.2 Absolute Maximum Ratings

Stresses beyond these limits may cause permanent damage.

• Power Dissipation per Segment: 70 mW
• Peak Forward Current per Segment: 60 mA (1/10 Duty Cycle, 0.1ms Pulse Width)
• Continuous Forward Current per Segment: 25 mA (Derating linearly from 25°C at 0.28 mA/°C)
• Operating Temperature Range: -35°C to +105°C
• Storage Temperature Range: -35°C to +105°C
• Soldering Temperature: 260°C for 5 seconds, measured 1/16 inch (≈1.6mm) below the seating plane.

3. Binning System Explanation

The device employs a binning system to categorize units based on their luminous intensity measured at 1 mA. This ensures consistency in brightness for applications requiring uniform appearance. The bins are defined as follows, with a luminous intensity tolerance of ±15% within each bin:

• Bin E: 201 - 320 ucd
• Bin F: 321 - 500 ucd
• Bin G: 501 - 800 ucd
• Bin H: 801 - 1300 ucd
• Bin J: 1301 - 2100 ucd
• Bin K: 2101 - 3400 ucd

The specific bin code for a unit is marked on the device packaging. Matching is also performed for dominant wavelength within a 4 nm delta for segments in similar light areas.

4. Performance Curve Analysis

The datasheet references typical electrical and optical characteristic curves. While the specific graphs are not detailed in the provided text, such curves typically illustrate the relationship between forward current (IF) and forward voltage (VF), the dependence of luminous intensity on forward current, and the variation of these parameters with ambient temperature. Analyzing these curves is crucial for circuit design to ensure proper current limiting, predict brightness under different drive conditions, and understand thermal effects on performance. Designers should expect the forward voltage to have a negative temperature coefficient, and luminous intensity to decrease as temperature increases.

5. Mechanical & Package Information

5.1 Package Dimensions

The display has a standard dual-digit seven-segment footprint. Key dimensional notes include:

• All dimensions are in millimeters.
• General tolerance is ±0.25 mm unless otherwise specified.
• Pin tip shift tolerance is ±0.4 mm.
• Defect limits are specified for foreign material on segments (≤10 mil), ink contamination (≤20 mil), bending of the reflector (≤1/100 of its length), and bubbles in segments (≤10 mil).
• A PCB hole diameter of Ø1.4mm is recommended for mounting.

5.2 Pin Connection and Polarity

The device uses a common anode configuration. The internal circuit diagram shows two common anodes (one for each digit) and individual cathodes for each segment (A-G and DP). The pinout is as follows:

• Pin 1: Cathode E
• Pin 2: Cathode D
• Pin 3: Cathode C
• Pin 4: Cathode G
• Pin 5: Cathode DP (Decimal Point)
• Pin 6: Common Anode (Digit 2)
• Pin 7: Cathode A
• Pin 8: Cathode B
• Pin 9: Common Anode (Digit 1)
• Pin 10: Cathode F

Proper identification of the common anode pins is essential for multiplexing the two digits.

6. Soldering & Assembly Guide

6.1 Soldering Profile

Automatic Soldering: The recommended condition is 260°C for 5 seconds, measured 1/16 inch (≈1.6mm) below the seating plane. The unit temperature during assembly must not exceed the maximum temperature rating.
Manual Soldering: The recommended condition is 350°C ±30°C for a maximum of 5 seconds, measured 1/16 inch below the seating plane.

6.2 Cautions & Application Notes

The display is intended for ordinary electronic equipment in office, communication, and household applications. For applications requiring exceptional reliability where failure could jeopardize life or health (e.g., aviation, medical systems), consultation prior to use is mandatory. Designers must strictly adhere to the absolute maximum ratings. Care should be taken during handling to avoid electrostatic discharge (ESD), although specific ESD ratings are not provided in this excerpt. Storage should be within the specified temperature range of -35°C to +105°C in a dry environment.

7. Packaging & Ordering Information

The standard packing specification is as follows:

• Units per Tube: 33
• Tubes per Inner Carton: 90
• Units per Inner Carton: 2,970
• Tubes per Outer Carton: 360
• Units per Outer Carton: 11,880

The module marking on the device includes the Part Number (LTD-2601JG-J), a Date Code (YYWW format), the Manufacturing Country, and the Bin Code (Z).

8. Application Suggestions

8.1 Typical Application Scenarios

This display is suitable for any device requiring a compact, bright, two-digit numeric readout. Common applications include instrument panels, consumer electronics (clocks, timers, scales), industrial controls, test and measurement equipment, and appliance displays.

8.2 Design Considerations

• Current Limiting: External current-limiting resistors are mandatory for each segment or common anode to prevent exceeding the maximum continuous forward current (25 mA per segment). The value must be calculated based on the supply voltage and the LED's forward voltage drop.
• Multiplexing: To independently control two digits with only 10 pins, a multiplexing technique is used. The common anodes (pins 6 and 9) are driven sequentially at a high frequency, while the appropriate segment cathodes are activated synchronously. This reduces the number of required microcontroller I/O pins.
• Viewing Angle: The wide viewing angle is beneficial for applications where the display may be viewed from off-axis positions.
• Brightness Control: Brightness can be adjusted by varying the forward current (within ratings) or by using pulse-width modulation (PWM) on the drive signals.

9. Technical Comparison & Differentiation

The key differentiators of the LTD-2601JG-J are its use of AlInGaP technology for green emission and its specific binning for luminous intensity. Compared to older technologies like GaP, AlInGaP offers higher brightness and efficiency. The explicit binning system provides designers with predictable brightness levels, which is critical for applications requiring visual consistency across multiple units or products. The 0.28-inch digit height positions it in a common size category, offering a good compromise between readability and board space.

10. Frequently Asked Questions (Based on Technical Parameters)

Q: What is the purpose of the bin code?
A: The bin code (marked as 'Z' on the device) indicates the luminous intensity range of that specific unit. This allows designers to select parts with consistent brightness for their application or to source a specific brightness level if required.

Q: Can I drive this display without current-limiting resistors?
A: No. Driving an LED directly from a voltage source will cause excessive current to flow, potentially exceeding the absolute maximum rating and destroying the segment. Always use series resistors.

Q: How do I control the two digits independently?
A: You must use multiplexing. Briefly turn on the common anode for Digit 1 while setting the cathodes for the desired segments of Digit 1. Then turn off Digit 1's anode, turn on Digit 2's anode, and set the cathodes for Digit 2's segments. Repeat this cycle rapidly (e.g., >60 Hz) to create the illusion that both digits are on continuously.

Q: What does "common anode" mean?
A: It means the anodes (positive sides) of all LEDs in a digit are connected together to one pin. To light a segment, you apply a positive voltage to its common anode pin and connect the cathode (negative side) of that specific segment to ground (or a low logic level).

11. Practical Design & Usage Case

Case: Designing a Simple Two-Digit Counter.
A microcontroller can be used to implement a counter from 00 to 99. Ten I/O pins are needed: two to drive the common anodes (preferably via transistors for higher current) and eight to drive the segment cathodes (A-G and DP). Firmware will maintain the count value, convert each digit to a 7-segment pattern, and execute the multiplexing routine. The current-limiting resistor value (R) for each segment can be calculated using Ohm's Law: R = (Vcc - Vf) / If, where Vcc is the supply voltage (e.g., 5V), Vf is the LED forward voltage (~2.6V), and If is the desired forward current (e.g., 10 mA). This gives R = (5 - 2.6) / 0.01 = 240 Ω. A 220 Ω or 270 Ω resistor would be suitable standard values.

12. Principle Introduction

The device is based on Light Emitting Diode (LED) technology. An LED is a semiconductor p-n junction diode that emits light when electrically biased in the forward direction. Electrons recombine with holes within the device, releasing energy in the form of photons. The color of the light (wavelength) is determined by the energy band gap of the semiconductor material. The LTD-2601JG-J uses AlInGaP, a material system well-suited for producing high-efficiency red, orange, amber, and green light. The seven-segment design uses multiple individual LED chips arranged in a standard pattern (segments A through G and a decimal point DP) to form numeric characters. The common anode configuration is a common circuit design that simplifies multiplexing for multi-digit displays.

13. Development Trends

While discrete seven-segment LED displays remain relevant for specific applications, broader trends in display technology include a shift towards integrated dot-matrix displays (which offer alphanumeric and graphic capability), organic LED (OLED) displays for their thinness and contrast, and the integration of driver circuitry and sometimes microcontrollers directly into the display module ("intelligent" displays). However, for simple, low-cost, high-brightness, and highly reliable numeric readouts, LED seven-segment displays like the LTD-2601JG-J continue to be a robust and effective solution, particularly in industrial, automotive, and appliance contexts where longevity and visibility under various lighting conditions are paramount.