SMT CBI LED LTLM11KF1H310U Datasheet - Amber Color - 2.0V Typ. - 72mW Max. - English Technical Document

1. Product Overview

The LTLM11KF1H310U is a Circuit Board Indicator (CBI) designed for surface-mount technology (SMT) assembly processes. It consists of a black plastic right-angle housing (holder) that integrates with a light-emitting diode. This component is engineered for applications requiring clear status indication on printed circuit boards (PCBs).

1.1 Core Features

• SMT Compatibility: Designed for automated pick-and-place and reflow soldering processes.
• Enhanced Contrast: The black housing material improves the visual contrast ratio of the illuminated indicator against the PCB background.
• High Efficiency: Offers low power consumption with high luminous efficiency.
• Environmental Compliance: This is a lead-free product compliant with the RoHS (Restriction of Hazardous Substances) directive.
• Optical Design: Utilizes an AlInGaP (Aluminum Indium Gallium Phosphide) semiconductor chip emitting amber light, coupled with a white diffused lens for a uniform, wide viewing angle.
• Reliability: Devices undergo preconditioning accelerated to JEDEC (Joint Electron Device Engineering Council) Moisture Sensitivity Level 3, ensuring robustness against moisture-induced damage during soldering.

1.2 Target Applications

This indicator LED is suitable for a broad range of electronic equipment, including:

• Computer peripherals and motherboards
• Communication devices and networking equipment
• Consumer electronics
• Industrial control systems and instrumentation

2. Technical Parameter Analysis

All specifications are defined at an ambient temperature (TA) of 25°C unless otherwise stated.

2.1 Absolute Maximum Ratings

These ratings define the limits beyond which permanent damage to the device may occur. Operation under these conditions is not guaranteed.

• Power Dissipation (Pd): 72 mW maximum.
• Peak Forward Current (IFP): 80 mA maximum. This rating applies under pulsed conditions with a duty cycle ≤ 1/10 and a pulse width ≤ 0.1 ms.
• Continuous Forward Current (IF): 30 mA DC maximum.
• Operating Temperature Range: -40°C to +85°C.
• Storage Temperature Range: -40°C to +100°C.
• Soldering Temperature: Withstands 260°C for a maximum of 5 seconds during reflow soldering.

2.2 Electrical & Optical Characteristics

These are the typical performance parameters under standard test conditions.

• Luminous Intensity (Iv): 8.7 mcd (minimum), 30 mcd (typical), 50 mcd (maximum) at a forward current (IF) of 10 mA. The Iv classification code is marked on each packing bag for binning purposes.
• Viewing Angle (2θ1/2): 40 degrees. This is the full angle at which the luminous intensity drops to half of its peak axial value.
• Peak Emission Wavelength (λP): 608 nm (typical). This is the wavelength at which the spectral power distribution is maximum.
• Dominant Wavelength (λd): 598 nm (minimum), 605 nm (typical), 612 nm (maximum) at IF=10 mA. This is the single wavelength perceived by the human eye that defines the color (amber).
• Spectral Line Half-Width (Δλ): 18 nm (typical). This indicates the spectral purity or bandwidth of the emitted light.
• Forward Voltage (VF): 1.8 V (minimum), 2.0 V (typical), 2.6 V (maximum) at IF = 10 mA.
• Reverse Current (IR): 10 μA maximum at a reverse voltage (VR) of 5V. Important Note: This device is not designed for operation under reverse bias; this test condition is for characterization only.

3. Binning System Explanation

The product employs a binning system to ensure color and performance consistency.

3.1 Luminous Intensity Binning

The luminous intensity (Iv) is classified into bins, with the specific bin code printed on the product's packaging bag. This allows designers to select LEDs with consistent brightness levels for their applications, which is critical for multi-indicator panels where uniform appearance is desired.

3.2 Wavelength Binning

The dominant wavelength (λd) is specified with a range from 598 nm to 612 nm. While not explicitly detailed as separate bins in this datasheet, the min/typ/max values indicate the controlled variation in color point (hue) across production lots. For applications with stringent color requirements, consulting the manufacturer for specific bin availability is recommended.

4. Performance Curve Analysis

Typical performance curves (referenced in the datasheet) illustrate the relationship between key parameters. While the specific graphs are not reproduced here, their implications are analyzed.

4.1 Forward Current vs. Forward Voltage (I-V Curve)

The I-V curve for an AlInGaP LED typically shows an exponential relationship. The specified forward voltage (VF) of 2.0V typical at 10mA is a key design parameter for calculating the series current-limiting resistor value in the drive circuit.

4.2 Luminous Intensity vs. Forward Current

Luminous intensity generally increases linearly with forward current in the normal operating range (up to the rated continuous current). Operating above 10mA will yield higher brightness but also increases power dissipation and junction temperature, which can affect longevity and color shift.

4.3 Temperature Dependence

LED performance is temperature-sensitive. The luminous intensity of AlInGaP LEDs typically decreases as the junction temperature increases. The specified operating temperature range of -40°C to +85°C defines the ambient conditions under which the published specifications are guaranteed.

5. Mechanical & Package Information

5.1 Outline Dimensions

The device features a right-angle (90-degree) mounting configuration, allowing the light to be emitted parallel to the PCB surface. This is ideal for edge-lit panels or status indicators viewed from the side of an enclosure. The housing material is specified as black plastic. Critical dimensional tolerances are ±0.25mm unless otherwise noted on the detailed mechanical drawing provided in the datasheet.

5.2 Polarity Identification

As a surface-mount device, polarity is indicated by the physical design of the component footprint on the tape and reel packaging and the corresponding pad layout on the PCB. Designers must strictly adhere to the recommended land pattern to ensure correct orientation during automated assembly and to prevent reverse biasing.

6. Soldering & Assembly Guidelines

6.1 Storage Conditions

• Sealed Package: Store at ≤30°C and ≤70% Relative Humidity (RH). The shelf life in the sealed moisture barrier bag (MBB) with desiccant is one year.
• Opened Package: If the MBB is opened, the storage ambient must not exceed 30°C and 60% RH. Components should be subjected to IR reflow soldering within 168 hours (7 days) of exposure. For storage beyond 168 hours, a 48-hour bake at 60°C is strongly recommended before SMT assembly to remove absorbed moisture and prevent "popcorning" damage during reflow.

6.2 Reflow Soldering Profile

A JEDEC-compliant reflow profile is recommended to ensure reliable solder joints without damaging the LED. Key parameters from the profile include:

• Preheat/Soak: 150°C to 200°C over a maximum of 100 seconds.
• Time Above Liquidous (T_L=217°C): 60 to 150 seconds.
• Peak Temperature (T_P): 260°C maximum.
• Time within 5°C of Specified Classification Temp (T_C=255°C): 30 seconds maximum.
• Total Time from 25°C to Peak: 5 minutes maximum.

Caution: Exceeding the peak temperature or time-at-temperature can cause deformation of the plastic lens or catastrophic failure of the LED die.

6.3 Cleaning

If post-solder cleaning is necessary, only alcohol-based solvents like isopropyl alcohol (IPA) should be used. Harsh or aggressive chemical cleaners may damage the plastic housing or lens.

7. Packaging & Ordering Information

7.1 Packing Specification

• Carrier Tape: Components are supplied on 13-inch reels. The carrier tape is made of black conductive polystyrene alloy, 0.40mm ±0.06mm thick.
• Quantity per Reel: 1,400 pieces.
• Inner Carton: Contains 3 reels (total 4,200 pcs), each sealed in a Moisture Barrier Bag (MBB) with a desiccant and humidity indicator card.
• Outer Carton: Contains 10 inner cartons (total 42,000 pcs).

7.2 Part Number

The base part number is LTLM11KF1H310U. This alphanumeric code uniquely identifies the product's specific attributes, including package type, color, brightness bin, and other manufacturing codes.

8. Application Design Considerations

8.1 Drive Circuit Design

LEDs are current-operated devices. To ensure stable and consistent light output, they must be driven by a current source or, more commonly, a voltage source with a series current-limiting resistor.

Recommended Circuit: A simple and effective drive method is to connect the LED in series with a resistor to a DC voltage supply (V_CC). The resistor value (R_S) can be calculated using Ohm's Law: R_S = (V_CC - V_F) / I_F, where V_F is the forward voltage of the LED (use 2.0V typical for design margin) and I_F is the desired forward current (e.g., 10mA).

Critical Note for Parallel Connections: When driving multiple LEDs from a single voltage source, it is strongly recommended to use a separate current-limiting resistor for each LED. Connecting LEDs directly in parallel without individual resistors is discouraged due to the natural variation in forward voltage (V_F) from device to device. This variation can cause significant current imbalance, where one LED may draw much more current than others, leading to non-uniform brightness and potential overstress and failure of the LED with the lowest V_F.

8.2 Thermal Management

While the power dissipation is relatively low (72mW max), proper thermal design extends LED life and maintains color stability. Ensure the PCB has adequate copper area connected to the LED's thermal pads (if any) or general board area to act as a heat sink, especially when operating at higher currents or in elevated ambient temperatures.

9. Technical Comparison & Differentiation

This SMT CBI LED differentiates itself through several key attributes:

• Right-Angle Form Factor: Unlike top-view LEDs that emit light perpendicular to the board, this right-angle design is optimal for side-emitting applications, saving vertical space within an enclosure.
• AlInGaP Technology: The use of AlInGaP for amber emission offers high efficiency and excellent color saturation compared to older technologies like filtered GaP.
• White Diffused Lens: The diffused lens provides a wide, uniform viewing angle (40°) and softens the appearance of the bright chip, creating a pleasant indicator light.
• JEDEC MSL3 Rating: The preconditioning to Moisture Sensitivity Level 3 provides assurance of reliability in standard SMT assembly environments.

10. Frequently Asked Questions (FAQ)

10.1 What is the purpose of the black housing?

The black housing serves two primary functions: 1) It increases the visual contrast between the illuminated LED and the surrounding area, making the indicator more noticeable. 2) It helps prevent light leakage or "crosstalk" between adjacent indicators on a densely populated PCB.

10.2 Can I drive this LED at 20mA instead of 10mA?

Yes, the absolute maximum continuous forward current rating is 30 mA. Operating at 20 mA will produce higher luminous intensity than the 10mA test condition. However, you must recalculate the series resistor value accordingly, ensure the total power dissipation (V_F * I_F) does not exceed 72mW, and consider the potential impact on long-term reliability due to increased junction temperature.

10.3 Why is baking required if the bag is opened for more than 168 hours?

Surface-mount plastic packages can absorb moisture from the atmosphere. During the high-temperature reflow soldering process, this trapped moisture can rapidly vaporize, creating internal pressure that may delaminate the package, crack the die, or damage the wire bonds—a phenomenon known as "popcorning." Baking at 60°C for 48 hours safely drives out this absorbed moisture before the component undergoes reflow.

11. Practical Design Example

Scenario: Designing a power "ON" indicator for a device powered by a 5V rail. The goal is to operate the LED at its typical current of 10mA.

1. Select Component: Choose the LTLM11KF1H310U for its right-angle amber light.
2. Calculate Series Resistor: R_S = (V_CC - V_F) / I_F = (5V - 2.0V) / 0.010A = 300 Ohms. The nearest standard E24 resistor value is 300Ω or 330Ω. Using 330Ω will result in a slightly lower current: I_F ≈ (5V - 2.0V) / 330Ω ≈ 9.1mA, which is safe and within specification.
3. Check Power Dissipation: In the resistor: P_R = I_F² * R = (0.0091)² * 330 ≈ 0.027W (a standard 1/8W or 1/10W resistor is sufficient). In the LED: P_LED = V_F * I_F ≈ 2.0V * 0.0091A ≈ 18.2mW, well below the 72mW maximum.
4. PCB Layout: Place the component according to the recommended land pattern. Ensure the polarity (anode/cathode) matches the footprint. Provide some small copper pour around the pads for minor heat dissipation.

12. Operating Principle

This LED operates on the principle of electroluminescence in a semiconductor p-n junction. The active region is composed of AlInGaP. When a forward voltage exceeding the junction's built-in potential is applied, electrons and holes are injected into the active region from the n-type and p-type layers, respectively. These charge carriers recombine radiatively, releasing energy in the form of photons. The specific composition of the AlInGaP alloy determines the bandgap energy, which directly defines the wavelength (color) of the emitted light—in this case, amber (~605 nm). The generated light is then shaped and diffused by the integrated white plastic lens to achieve the desired viewing angle and appearance.

13. Technology Trends

The development of indicator LEDs like this one follows broader trends in optoelectronics and SMT assembly:

• Increased Efficiency: Ongoing material science improvements aim to produce higher luminous efficacy (more light output per unit of electrical input power), allowing for lower operating currents and reduced system energy consumption.
• Miniaturization: There is a continuous drive towards smaller package footprints and heights to accommodate ever-shrinking consumer and industrial electronics.
• Enhanced Reliability: Improvements in packaging materials, die attach techniques, and moisture resistance (higher MSL ratings) contribute to longer operational lifetimes and robustness in harsh environments.
• Integration: A trend exists towards integrating additional functionality, such as built-in current limiting resistors ("resistor-equipped LEDs") or even IC drivers within the package, simplifying circuit design and board layout.