LED test: Seoul Semiconductor SunLike 3030 (6V, 3000/4000/5000/5700K, CRI95)

Quick test of the Seoul Semiconductor SunLike SMD3030 LED.

What makes these interesting is the smooth spectrum rivaling and exceeding that of the Nichia Optisolis.

Datasheet: http://www.seoulsemicon.com/en/product/spec/\_91_SunLike_92\_%20STW9C2SB-S/31

Part name: STW9C2SB-S
Forward voltage: 6V
Max current: 200mA
CRI: Min. Ra 95, R9 85
Luminous flux: Min. 83-104 at 150mA depending on CCT and flux bin
Efficacy: ~108 lm/W (again depends on the bin)
Emitter package size: 3x3mm

I got these from user SunLike from sunlikelamp.com

The unusual size and solder pad configuration combined with 6V forward voltage (also available in 3V, which djozz tested previously) makes these a bit difficult for most flashlight modding purposes. Can’t use the normal 3535 XP MCPCB for these.

An MCPCB for Optisolis, such as the VR10S1-757 from virence.com could probably be used for these as well. My emitters were reflowed on a board from SunLike. These are used on a variety of bulbs he also sells.

Previous bulb tests with SunLike 3030:
Remez SunLike E14 LED bulb (3000K, CRI95)
Remez SunLike E27 LED bulb (5700K, CRI95)
SunLike8 SMD SAW E27 LED bulb (4200K, CRI98)


I tested the 5000K LED for maximum output and tint shift with increasing current.

Output peaks at 228 lumens at 500mA / 3.7W.

Tint behaves quite predictably and turns quickly more magenta after the peak output. At the nominal driving current of 150mA the tint is very close to daylight, which isn’t surprising considering the LED’s name.

CRI data for all the emitters

Excellent CRI and very pleasant tint on the warmer versions, while the higher CCTs are tracking the daylight tint above the BBL.





2 Thanks


Test of efficiency really helpful!

Great job! (Or hobby)

Seoulsemiconductor say that it is CRI:97 typical. Old 3v 3030 was 95

You can solder it to pcb 3535 with 3 contacts, but it will not be so easy. You must move it to correct place when solder is liquid.

It will not be very good in a flashlight because it would be offset to the side in reference to the reflector though.

Just curious

  • When was this LED model released?
  • What is the typical waiting time between LED release date and when it becomes widely adopted in flashlight?

Yes, but just try =)

For flashlights I think big problem is low power of this leds. With this size of crystals I think it is about 2x0.2w

I just compared the datasheets. The solder pads have the same polarity, and dimensions only differ by about 0.1mm in a couple places. I’d say it is a near certainty that Clemence’s 757-compatible PCB’s will work.

The VR10S1-757 has been out of stock for a couple of months, though. Clemence does have a 757 quad board, though.

I’m still in awe of the 4000K spectrum. Seems like that’s been the hardest one to nail down, and these SunLike emitters do a pretty darn good job. I found that Digikey has almost the full range of SunLike emitters in stock… looks like I’ll have to order a variety and try them myself. I even have a few A19 bulbs with 3030 footprint emitters in them I could swap out :partying_face: I’m excited. Now I just need to find more mcpcb’s for these…

Thanks Maukka and SunLike! As always, your work is always the best! :+1:

The 3000K and 4000K looks sweet. Too bad the output and efficiency is too low for flashlight use.

The footprint is not unusual, almost all 3030 mid power LEDs are like that

Four of these will fit on an XM board as djozz and others have done. . Find some 20mm XHP70 TIR optics (Clemence also has his Carclo quad 757 board) and you can have an 790lm (emitter) 98Rf flood beam. A mild 1.5A@6V boost driver or 4x7135 zener from 2S cells are just two simple options that open up a lot of possibilities. [[Mini-mag mule from 2x14500 coming up]]

A single SST20 4000k running at the equivalent 10Watts (~3050mA) would be producing only 730lm. A 5000K LH351D would be at 1000lm at roughly the same current, but with a notably lower 90Rf and R9/R12 ~70. Granted, it’s a lot simpler to drive and also provide a wide range of optic choices, but if you’re going for a flood/mule setup, this surely could be used without major penalty.

I politely invite BLFer’s to reconsider and re-calibrate our lumen crazy minds. 10W is about as much as anyone will need in the majority of use cases. As time passes, I come to love and respect even single mode ~200-500 lumen lights with great beams and CRI. YMMV


I’m thinking, I see a 6 V and 1 A driver - 17mm MTN-BST2 Boost Driver it turns out according to maukka graph gives about 540 lumens for 3 diodes, not so little, I would even say a lot. We already have diode boards for size 3030. I think to insert them into Jaxman E2L, but won’t it overheat? Now he has 3 * 219С and 3 amperes through the switch, if apply 4 amperes, will the switch fail?

I agree 6V 1A driver and virence 757 board could be a killer combo.