Dual-State Indicators

Dual-colour LED packages contain two independent LED dies in a single footprint, enabling one component to communicate two distinct states without doubling PCB area or BOM complexity. The most common configuration is red/green — used for OK/Fault, Active/Standby, and Charged/Fault indications. Red/amber configurations serve applications where two warning states must be distinguished from a normal green condition.

The electrical interface is straightforward: each die has its own anode connection with a shared cathode (common cathode) or shared anode (common anode), allowing independent drive of each color. Both dies driven simultaneously produce a mixed color — red + green produces amber in common cathode packages — enabling a three-state indicator from a two-die component. Footprint efficiency is the primary design driver: replacing two single-color LEDs with one dual-color package reduces land pattern area by nearly 50%.

Dual-colour indicator LEDs serve three strong North American markets:

• Power conversion and UPS systems — every redundant power supply in a server, switch, or storage array requires a dual-state indicator for OK/Fault signalling. With hundreds of millions of PSUs shipped annually globally, volume is substantial
• Network switching and routing equipment — uplink port status (active/standby), PoE status (powered/fault), and SFP presence indicators commonly use dual-colour packages to communicate multiple states in a single LED footprint
• Alarm and annunciator panels — industrial safety and building management systems use dual-colour LEDs in annunciator panels to indicate normal/alarm state for each monitored point, where space for two separate LEDs per point is not available

The dual-colour segment commands a price premium over equivalent single-color SMD LEDs and requires tighter binning matching between the two dies within each package — a quality requirement that benefits from single-factory sourcing.

• Redundant server power supply: Each PSU bay in a 2U server has a single dual-color LED (green=operating, red=failed) — replacing two single-color LEDs saves space in the densely packed PSU indicator strip
• Managed switch uplink port: Uplink SFP+ ports use dual-color indicators for link status (green=1G active, amber=10G active) and fault detection (red=no link)
• Generator transfer switch panel: An automatic transfer switch uses dual-colour indicators across 12 circuit positions to show Normal vs. Generator source selection simultaneously
• Building management annunciator: A 64-point annunciator panel uses dual-colour LEDs to show normal (green) vs. alarm (red) for each monitored input point, in a panel where single-color dual-LED layouts would not fit

Dual-colour packages require consistent binning not just within each color, but between the two dies in every package. A red/green package where the green die shifts wavelength between production runs creates visible inconsistency in mixed-state indications. CMH's single-factory production ensures die characteristics remain stable across orders.

iBright's direct relationship with CMH also allows discussion of custom IV ratios between the two dies for high-volume applications where a specific brightness balance between red and green states is required — a conversation structurally impossible with intermediary distributors sourcing from multiple factories.