SFT-25R-WS65-A2-ENG(F6-VJ-AG)
2024-08-10
- Type: round die, domeless
- Bin: unknown
- Color group: unknown (6500 K)
- CRI: 70
- Rated voltage: — V
- Max. Forward current: — mA
- Max. Peak current: — mA
- Viewing angle: — °
- Thermal resistance: — K/W
- Max. Temperature Tj: max. —°C
Attention: An official data sheet and further information are not available for this emitter. Official details can therefore not be provided in the course of the test. Although excerpts of a data sheet are already circulating on Reddit, as this has not been published in full and the order code cannot be decrypted, it must still be assumed that there are no official specifications.
The emitter was regularly purchased from Convoylight at the beginning of August 2024.
The SFT-25R is 3.45 x 3.45 mm in size. It looks very similar to the previously introduced and tested SFT-12. The only differences are the round illuminated surface and the number of bonding wires. A silver metal frame is located on the substrate and is covered with white silicone. It can already be seen that the SFT-25R has an LED chip with a round illuminated surface, similar to other round-die LEDs. The factory-domed SFT variants from Luminus are often identical to the SST models, although in this case the illuminated surface of the SST-25 does not match the circular LES of the SFT-25R. This is possibly also the reason for the suffix “R”.
This LED uses the standard 3535, so all accessoires for this footprint will fit.
Bondings are attached to each corner of the LED chip with it’s circular LES. They do not affect the light pattern due to the round surface. The LED chip is 2.25 mm² in size.
- Maximum reached at 8.2 A, at this point 2013 lm @ 3.84 V
- Power at maximum 31.5 W
- Efficiency at maximum 63.9 lm/W
Data for 25 °C Tsp (at 85 °C the luminance values are around 13 % lower).
There were already statements in advance that the forward voltage of the SFT-25R was very high and that the tint was often very green, as with Luminus.
Neither can be confirmed in the test. The Vf remains pleasingly low and also enables use with FET-based drivers. However, operation in direct drive is not recommended, as the maximum possible current could be exceeded depending on the voltage level. The SST-25 used as a comparison has a much higher Vf, which reduces its efficiency.
All in all, the SFT-25R is state of the art in terms of performance and is already quite efficient in this presumably pre-production specimen.
The luminance is in the range of other LEDs with a small luminous surface. As the SFT-25R has not yet been officially released and this sample presumably comes from a pre-production run, it is possible that flux binnings will be increased in later samples, thus significantly increasing the luminous area.
The beam is perfectly fine. Depending on the focus and reflector calculation, slight rings may appear. There are no color distortions in spot or spill.
The tint is pleasingly good. Although the SFT-25R has the extreme tint shift typical of Luminus with increasing current and at low currents it has a minimal green tint, from 1.5-2 A this slips into a clear and ultimately slightly reddish blue-white.
However, it should be noted here that the dispersion is likely to be significant and there will also be very green specimens in circulation.
There are no other surprises in the spectrum. The spectrum corresponds to that of a cool white LED with a CRI of 65-70.
- Ra: 69
- R9: -27
- CCT: 7204 K
- duv: 0.0010
In current state, the SFT-25R is not a game changer. The luminance is within the expected range of CSLPM1.TG, Black Flat and co. Nevertheless, its overall package provides a significant improvement for 3535 LEDs with high luminance. Until now, other emitters have had more or less significant disadvantages, such as poor beam, strange footprints, connected thermal pad or poor availability and a lack of information.
It can be assumed that the SFT-25R will soon appear at wholesalers such as Mouser, so that proper documentation is guaranteed.
It is also very likely that this LED will play an important role for (pocket) throwers in the future, especially in higher flux binnings, which are likely will released in the next years.
Thank you for reading this test. 
