SMD RGB LED with Integrated Driver IC - 3.2mm x 2.8mm x 1.9mm - 5V - 220mW - Red/Green/Blue - English Datasheet

1. Product Overview

This document details the specifications for a miniature, surface-mount RGB LED module designed for automated assembly and space-constrained applications. The device integrates three individual LED chips (Red, Green, Blue) with an embedded 8-bit constant current driver IC within a single package. This integration simplifies circuit design by eliminating the need for external current-limiting resistors and PWM controllers for each color channel.

The core advantage of this product is its digital addressability. Each of the three color channels can be independently controlled with 256 steps of brightness (8-bit resolution), enabling the creation of over 16 million colors. The integrated driver communicates via a single-wire serial interface, significantly reducing the number of microcontroller I/O pins required for control, especially in multi-LED arrays.

Its primary target markets include consumer electronics, telecommunications equipment, office automation devices, home appliances, and industrial control panels. Typical applications are backlighting for keypads and keyboards, status indicators, micro-displays, and low-resolution signage where precise color control and compact size are critical.

1.1 Key Features

• Compliant with RoHS environmental directives.
• Utilizes high-efficiency AlInGaP (Red) and InGaN (Green, Blue) semiconductor materials for high luminous intensity.
• Integrated 3-channel constant current driver with 8-bit PWM control for each channel (256 brightness levels).
• Minimum data scan frequency of 800 kHz, suitable for dynamic lighting and multiplexing applications.
• Packaged in 8mm tape on 7-inch reels for compatibility with high-speed automated pick-and-place equipment.
• Standard EIA package footprint for design consistency.
• Direct logic-level interface compatibility (3.3V/5V).
• Designed to withstand standard infrared (IR) reflow soldering processes.

2. Technical Parameter Analysis

2.1 Absolute Maximum Ratings

Operating the device beyond these limits may cause permanent damage.

• Power Dissipation (P_D): 220 mW. This is the maximum total power the package can dissipate as heat.
• IC Supply Voltage (V_DD): +4.2V to +5.5V. The driver IC requires a regulated 5V supply within this range.
• Total Forward Current (I_F): 40 mA DC. This is the maximum sum of currents for all three LED channels combined.
• Operating Temperature (T_op): -20°C to +85°C. The ambient temperature range for reliable operation.
• Storage Temperature (T_stg): -30°C to +85°C.
• ESD Sensitivity (HBM): The embedded IC is rated for 4kV. The LED chips themselves are more sensitive: Red ~2kV, Green/Blue ~300V. Proper ESD handling procedures are mandatory.

2.2 Electro-Optical Characteristics (at T_a=25°C, V_DD=5V)

These are typical performance parameters under specified test conditions.

• Luminous Intensity (I_V):
  • Red: 180 - 710 mcd (typical bin-dependent)
  • Green: 560 - 1400 mcd (typical bin-dependent)
  • Blue: 90 - 355 mcd (typical bin-dependent)
  Measured with all channels at full brightness (PWM code 255).
• Viewing Angle (2θ_1/2): 120 degrees. This wide viewing angle is characteristic of the water-clear lens package, providing a broad, diffuse light emission pattern.
• Dominant Wavelength (λ_d):
  • Red: 618 - 626 nm
  • Green: 522 - 530 nm
  • Blue: 466 - 474 nm
  Defines the perceived color of each LED channel.
• IC Output Current per Channel (I_F): Typically 12 mA per color (Red, Green, Blue) when driven by the internal constant current driver.
• IC Quiescent Current (I_DD): Typically 1.0 mA when all LED outputs are off (all data '0').

2.3 Data Transfer Protocol

The integrated driver uses a precise serial communication protocol. Data is clocked in via the DIN pin on the rising edge of the signal.

• Bit Encoding:
  • Logic '0': High time (T_0H) = 300ns ±150ns, Low time (T_0L) = 900ns ±150ns.
  • Logic '1': High time (T_1H) = 900ns ±150ns, Low time (T_1L) = 300ns ±150ns.
  • Total bit period (T_0H+T_0L or T_1H+T_1L) = 1.2 µs ±300ns.
• Data Frame: 24 bits of data are required for one LED: 8 bits for Green brightness, 8 bits for Red brightness, and 8 bits for Blue brightness (G7...G0, R7...R0, B7...B0).
• Latch Signal: After sending the 24-bit data frame, a low pulse on the DIN pin lasting longer than 250 µs (LAT) latches the data into the driver's output registers, updating the LED brightness. During this latch time, new data for the next LED in a chain can begin transmission on the DOUT pin.

3. Bin Ranking System

To ensure color and brightness consistency in production, devices are sorted into bins based on measured performance.

3.1 Luminous Intensity Binning

LEDs are grouped by their measured light output at full drive current.

• Red: Bins S (180-280 mcd), T (280-450 mcd), U (450-710 mcd). Tolerance ±15% within bin.
• Green: Bins U (560-900 mcd), V (900-1400 mcd). Tolerance ±15% within bin.
• Blue: Bins R (90-140 mcd), S (140-224 mcd), T (224-355 mcd). Tolerance ±15% within bin.

3.2 Dominant Wavelength (Hue) Binning

LEDs are grouped by their precise color point (wavelength).

• Red: Bins U (618-622 nm), V (622-626 nm). Tolerance ±1 nm within bin.
• Green: Bins P (522-526 nm), Q (526-530 nm). Tolerance ±1 nm within bin.
• Blue: Bins C (466-470 nm), D (470-474 nm). Tolerance ±1 nm within bin.

A complete device order code includes bin selections for intensity and wavelength for each color, allowing designers to specify the exact performance grade required for their application, crucial for color-matching in multi-LED installations.

4. Mechanical and Packaging Information

4.1 Package Dimensions

The device conforms to a standard surface-mount package outline. Key dimensions (in mm) are: approximately 3.2mm in length, 2.8mm in width, and 1.9mm in height (subject to the detailed drawing in the source document). Tolerances are typically ±0.1mm unless otherwise specified. The water-clear lens aids in color mixing and provides a wide viewing angle.

4.2 Pinout and Polarity

• Pin 1 (V_DD): Positive power supply input for the driver IC (+5V).
• Pin 2 (DIN): Serial data input for the driver IC.
• Pin 3 (V_SS): Ground connection.
• Pin 4 (DOUT): Serial data output. This pin carries the data signal to the DIN pin of the next LED in a daisy-chain configuration, enabling control of long strings with only one microcontroller data line.

4.3 Recommended PCB Land Pattern

A suggested solder pad layout is provided to ensure reliable soldering and proper thermal management. The design typically includes thermal relief connections and adequate pad size to facilitate good solder joint formation during reflow and to act as a basic heat sink, helping to keep the LED junction temperature within safe limits.

5. Assembly and Handling Guidelines

5.1 Soldering Process

The device is compatible with lead-free (Pb-free) infrared (IR) reflow soldering processes. A recommended profile is provided, typically peaking at 260°C for a duration not exceeding 10 seconds. It is critical to follow this profile to prevent thermal damage to the LED chips, the epoxy lens, or the internal wire bonds.

5.2 Cleaning

If post-solder cleaning is necessary, only specified solvents should be used. Immersing the LED in ethyl alcohol or isopropyl alcohol at room temperature for less than one minute is acceptable. The use of aggressive or unspecified chemicals can damage the package material or optical properties of the lens.

5.3 Storage and Handling

• ESD Protection: The device, particularly the Green and Blue chips, is sensitive to electrostatic discharge. Use grounded wrist straps, anti-static mats, and properly grounded equipment during handling.
• Moisture Sensitivity: The package is sealed. For long-term storage (up to one year), it is recommended to keep the devices in their original moisture-barrier bag with desiccant at conditions of 30°C or less and 90% relative humidity or less.
• Thermal Management: Although the package has a power dissipation rating, a good thermal design on the PCB is essential. The soldering pads should be connected to a sufficient copper area to act as a heat sink, ensuring the operating temperature (measured at the solder pad) remains below 85°C for long-term reliability.

6. Packaging for Production

The devices are supplied on embossed carrier tape for automated assembly. The tape is 8mm wide and wound onto standard 7-inch (178mm) diameter reels. Each reel contains 4000 pieces. The tape is sealed with a cover tape to protect components. Packaging follows ANSI/EIA-481 standards. For smaller quantities, a minimum pack of 500 pieces is available.

7. Application Notes and Design Considerations

7.1 Typical Application Circuit

The basic application requires minimal external components: a stable 5V power supply with adequate current capability and a decoupling capacitor (typically 0.1µF) placed close to the V_DD and V_SS pins. A microcontroller GPIO pin, configured for digital output, connects to the DIN pin of the first LED in a chain. For multiple LEDs, the DOUT of the first connects to the DIN of the second, and so on. A single data line from the microcontroller can thus control a theoretically unlimited number of LEDs, with the latch signal updating them simultaneously.

7.2 Design Considerations

• Power Supply Stability: The 5V supply must be clean and stable, especially when driving long chains of LEDs, as voltage drops can affect the logic levels and brightness consistency.
• Data Signal Integrity: At high clock rates (up to ~800kHz) and in long daisy chains, signal integrity becomes important. PCB trace lengths should be minimized, and in very long runs, buffering or signal conditioning may be necessary.
• Current Load: Calculate the total current draw: (Number of LEDs) * (I_DD per IC) + (Number of lit channels per LED * I_F per channel). Ensure the power supply and PCB traces can handle this load.
• Heat Dissipation: When driving LEDs at or near maximum current, ensure the PCB's thermal design can dissipate the heat. This may involve using thicker copper, thermal vias, or even external heatsinks for high-density arrays.

7.3 Comparison with Discrete Solutions

The primary advantage over using three discrete LEDs with external drivers is component count reduction and simplified control. A discrete design requires three current-limiting circuits (resistors or transistors) and three PWM signals from a microcontroller. This integrated solution requires only one power connection, one ground, and one or two data lines, freeing up microcontroller resources and reducing PCB layout complexity, which is vital in miniaturized designs.

8. Technical Deep Dive and FAQs

8.1 How does the 8-bit PWM control work?

The integrated driver IC contains a constant current source for each LED channel. The 8-bit data value for each color (0-255) controls the duty cycle of an internal high-frequency PWM generator that switches this current source on and off. A value of 0 means the LED is off 100% of the time; 255 means it is on 100% of the time at the fixed current (e.g., 12mA). Values in between create proportional brightness levels. This method is more efficient and provides more consistent color than analog voltage control.

8.2 What is the purpose of the 800kHz minimum scan frequency?

This high refresh rate serves two main purposes. First, it eliminates visible flicker to the human eye, even during rapid brightness changes or animations. Second, in multiplexed applications where one controller drives many LEDs sequentially, a high data rate allows more LEDs to be updated within a given time frame while maintaining a flicker-free appearance.

8.3 Can these LEDs be used for constant illumination, or are they only for indicators?

While suitable for status indicators, their high brightness and precise color control make them excellent for functional illumination in compact spaces, such as keyboard backlighting or decorative accent lighting. The 120-degree viewing angle provides broad, even coverage. For constant-on use, thermal management is the critical design factor to ensure long-term reliability.

8.4 What happens if the data timing is slightly out of specification?

The driver IC has internal logic designed to recognize the 300ns/900ns pulse ratios. Slight deviations within the specified tolerances (±150ns) will typically be tolerated. However, signals too far outside this range may not be decoded correctly, leading to corrupted color data. It is important to generate the control signal with a precise timer or a hardware peripheral (like SPI or a dedicated LED driver output) on the microcontroller.