How to choose SMD indicator beads for 0603/0805/1206? Size, color, brightness comparison and pit avoidance list
Surface mounted indicator light beads are the most commonly used category of light beads on home appliances, 3C, and industrial control panels, with specifications 0603, 0805, and 1206 accounting for over 80%. There are only three specifications, but engineers come every week to ask questions such as "Is 0603 bright enough?" "What is the difference between 0805 and 1206?" and "Can different colors be mixed for the same size.
This article compares and clarifies the three mainstream specifications at once.
1、 Size and power comparison
| Packaging (Imperial) | metric dimensions | Typical power | Rated Current | Typical brightness (white light reference) |
|---|---|---|---|---|
| 0603 | 1.6×0.8mm | 0.06W | 20mA | 80-300 mcd |
| 0805 | 2.0×1.25mm | 0.08W | 20-25mA | 150-500 mcd |
| 1206 | 3.2×1.6mm | 0.12W | 20-30mA | 300-1000 mcd |
How to choose:
- 0603Space constraints, low power priority - TWS charging case, remote control, small appliance touch panel
- 0805The most universal choice, brightness/size/cost balance - router, set-top box, charging station panel
- 1206To achieve brightness and a wide viewing range - instruments, industrial control equipment, outdoor equipment
Pay attention to a common misconception: 0805 is not as simple as the "0603 enlarged version". The luminous area is about twice that of the "0603 enlarged version", and the brightness can be twice that of the same level. The difference in appearance is more obvious after passing through the light guide column/frosted panel.
2、 Same packaging but different colors, with significant differences in electrical parameters
| Color | VF @20mA | Characteristics of same level brightness | Selection Tips |
|---|---|---|---|
| Red | 1.8-2.2V | High brightness efficiency | Cheapest, preferred for power indication |
| Yellow/Orange | 1.8-2.2V | Close to Red | Pay attention to the discrimination when placed side by side with red light |
| Pu Green | 1.8-2.2V | Slightly yellow green, moderate brightness | Traditional 'running light' color |
| Pure green | 2.8-3.4V | Positive color, lower light effect than red | Separate calculation for current limiting when mixed with red light |
| Blue | 2.8-3.4V | Weak human perception | Suggest selecting a highlight file |
| White | 2.8-3.4V | Color temperature Bin must be locked | Clearly define color temperature (such as 6000-6500K) and display index |
Mixed color panel iron lawLow voltage colors (red/yellow/orange/plain green) and high voltage colors (pure green/blue/white) cannot share one current limiting circuit, and the current limiting resistors should be calculated separately.
3、 5 Must Check Items for SMT Selection
1. Brightness gradingSame package, same color, brightness level difference of 2-3 levels. Is it sufficient to use the frosted panel? It must be estimated according to "panel transmittance x lamp bead IV". If unsure, apply for two levels of sample testing
2. beam angle: Conventional 120 ° -140 °; Choose narrow angle (60 ° -90 °) spotlight for occasions with light guide columns, which doubles the light utilization rate
3. Side illumination or positive illuminationDue to structural limitations (the light position emits light on the edge side of the PCB), choose 0602/0802 side emitting packaging instead of using positive emitting hard conversion
4. Tape packaging and throwing rateSMT material throwing rate for specifications 0603 and above is normal<0.3%. Lamp beads with poor consistency in incoming size will significantly increase the throwing rate. During the trial production stage, this number should be monitored
5. Moisture proof grade (MSL)After the lamp bead absorbs moisture and undergoes reflow soldering, it will "pop popcorn" and crack the adhesive. After opening, it should be managed according to MSL3 (workshop exposure ≤ 168 hours), and must be baked at 60 ℃ for dehumidification if stored for a long time
4、 Welding process red line
- Reflow soldering peak ≤ 260 ℃, within 10 seconds, up to 2 times
- Iron repair ≤ 320 ℃/3s, iron tip does not touch gel
- Do not touch the lamp beads before cooling (the gel softens at high temperatures, external forces can cause the gold wire to break)
- Sulfur containing materials (some rubber, tape, cardboard boxes) should be kept away from the storage area of LED chips - blackening due to vulcanization is the first major non electrical cause of darkening of surface mount LED chips
5 FAQ
Q: Can 0603 replace 0805?
The solder pads are incompatible and cannot be directly replaced. Under the premise of sufficient brightness during the redesign, 0805 → 0603 is a common direction for cost reduction, while the reverse direction depends on space.
Q: Why is the brightness of light beads from different manufacturers of the same model twice as different?
The chip size (mil number), phosphor scheme, and bracket reflection efficiency are all different. 0805 White Light "is just a package name, and the selection must lock the brightness level (such as 400-500mcd level).
Q: Do surface mount light beads have positive and negative silk screen printing?
Yes, there are polarity markings (green dots/cut corners/T-shaped markings) on the back/side. Each company has different marking habits, so please check the specifications before going online for incoming materials.
6、 Summary
Three sentence selection of surface mount indicator beads:Space fixed packaging (0603/0805/1206), color fixed voltage (low-voltage color/high-voltage color separate current limiting), panel fixed brightness level (measured brightness after light transmission).
Hongcheng Optoelectronics 0603/0805/1206 patch indicator beads have full-color coverage (red/yellow/orange/plain green/pure green/blue/white), narrow brightness sorting, 3000 pieces/disc standard tape, and support free sample dual level comparison. Contact information: 139 2571 4318 (same WeChat account), sales@led-hc.com .
