Citizen Tunable White COB: 2700 K to 6500 K from one source

Citizen Electronics has developed a CITILED Tunable White COB series for spotlights and downlights, and started taking orders this June. Two package types, the CLUD32 and CLUD22, tune from 2700 K to 6500 K at Ra 90 or better, and Citizen's main claim is that the warm and cool light is already mixed inside the package, so a tunable spot can be small and narrow without colour blotches in the beam.

The problem with tunable spots

A tunable white source has two sets of LEDs, one warm and one cool. In a wide-beam panel that hardly matters, but once a lens or reflector narrows the beam, the optic tends to project the pattern of the source onto the wall. With two colours, that shows up as uneven intensity and colour across the spot. The usual fix is extra mixing in the optic or the fitting, which costs light and makes the fixture bigger.

Citizen's approach puts two colour emitting areas in one COB, with a package structure designed to mix them at the source. The result, according to Citizen, is a clean spot even at narrow angles without large optical losses, and lens design becomes simpler. That is what makes smaller, narrower tunable fixtures practical.

Four views of the same meeting room lit at different colour temperatures, from cool white on the left to warm white on the right — One room from high to low colour temperature. Image: Citizen Electronics.

Efficiency and the numbers

Citizen also reworked the LED chips and phosphor mix. Against its own earlier tunable product, it quotes 23 % better luminous efficiency at 2700 K and 16 % at 6500 K. The CLUD32 datasheet, dated June 2025, gives these typical figures at 180 mA per channel and a case temperature of 25 °C:

CLUD32	Flux	Efficacy	Forward voltage
2700 K	869 lm	139 lm/W	34.8 V
6500 K	943 lm	151 lm/W	34.8 V

The package is 19 x 19 x 2.0 mm with four terminals, one pair per colour. Maximum drive current is 480 mA, and that is the total of both channels, not each. Both colour points sit within a 3-step MacAdam ellipse.

Citizen CLUD22 Tunable White COB, a square white package with a round emitting area striped in warm and cool phosphor — The smaller CLUD22. Image: Citizen Electronics.

Where it fits

Citizen aims the series at shops and restaurants, and at circadian-style schemes where light shifts from cool in the day to warm in the evening. In this region the obvious uses are hotel lobbies and restaurants that change scene through the day, and retail where the same spot has to flatter different products.

On the control side, a two-channel COB needs a two-channel driver. Helvar's DALI tunable white drivers, such as the LC45iC-DA-100-900 G2, control colour temperature over DALI DT8; check the current window against the COB before you pair them.

Datasheets are on Citizen's Tunable White COB page. For samples, or a COB and driver pairing for a tunable spot, contact us or browse our components range.