Are there different versions of the Worldsemi WS2803S  - Page 1
Forum section: electronics / projects

author: PeterFW
author_rank: Frequent Contributor
timestamp: January 21, 2016, 04:40:29 pm
content: Hello!Has annyone encountered different versions of the WS2803S in the wild?I have 30 SSOP28 new ones, none of wich work in the same circuit the old ones i bought years back.I mean, my old chips work in the circuit, the new ones do not and i can not find a difference or fault.Greetings,Peter

author: PeterFW
author_rank: Frequent Contributor
timestamp: January 23, 2016, 11:14:11 pm
content: Yes there are and they are not pin compatible.Lesson learned, allways buy new stock when building a prototype.

author: Yansi
author_rank: Super Contributor
timestamp: January 24, 2016, 08:18:55 pm
content: So what was the difference?

author: PeterFW
author_rank: Frequent Contributor
timestamp: January 25, 2016, 01:21:10 am
content: Quote from: Yansi on January 24, 2016, 08:18:55 pmAsked Worldsemi and got a Email with the correct datasheet for the "new" version.The Website still listed the old one last time i checked.Nice trap... snipping all those legs and puting bodge wires in is fun.

author: Mr.B
author_rank: Unknown
timestamp: January 25, 2016, 01:26:41 am
content: Why on earth would a manufacturer do that.Why not create a "WS2803Sb"

author: Monkeh
author_rank: Super Contributor
timestamp: January 25, 2016, 01:30:26 am
content: What on earth..And people willingly buy from this company?!

author: wraper
author_rank: Unknown
timestamp: January 25, 2016, 01:31:17 am
content: According to the datasheet, the "new stock" have the pinout of DIP-28 package, not what SOP-28 should have. Something fishy here, most likely those are improperly made counterfeits.

author: wraper
author_rank: Unknown
timestamp: January 25, 2016, 01:36:59 am
content: The new stock also have a center aligned marking instead of a left aligned and a different date code format.

author: Len
author_rank: Frequent Contributor
timestamp: January 25, 2016, 01:59:33 am
content: Quote from: wraper on January 25, 2016, 01:31:17 amPeter said that he got the new datasheet from Worldsemi directly so it seems legit.

author: wraper
author_rank: Unknown
timestamp: January 25, 2016, 02:04:29 am
content: Quote from: Len on January 25, 2016, 01:59:33 amDidn't notice about the datasheet.

author: wraper
author_rank: Unknown
timestamp: January 25, 2016, 02:12:13 am
content: If those pins are really NC (what most likely can be checked by measuring if there are ESD protection diodes on them) and are not connected to the die, then universal PCB for both versions can be made. Also in such a case there is no need to snip the pins, just connect the needed pins together.

author: Mr.B
author_rank: Unknown
timestamp: January 25, 2016, 02:50:56 am
content: Quote from: wraper on January 25, 2016, 02:12:13 amIt is still just bollocks that a manufacturer would do such a thing.I totally agree with Monkeh.Quote

author: wraper
author_rank: Unknown
timestamp: January 25, 2016, 03:01:29 am
content: Quote from: Mr.B on January 25, 2016, 02:50:56 amOf course it is. Just seems there is relatively easy workaround to deal with this stupidity.

author: Mr.B
author_rank: Unknown
timestamp: January 25, 2016, 03:12:24 am
content: Quote from: wraper on January 25, 2016, 03:01:29 amAs you said, if they are genuinely NC, then there is a workaround for the initial design.However you are a bit stuffed if you have to repair an old design and can only source new components...Thats when the bodge wires come in I guess.

author: PeterFW
author_rank: Frequent Contributor
timestamp: January 25, 2016, 10:44:54 pm
content: Both datasheets are from Worldsemi, one from the website, the other one i got from a sales rep after asking them directly.So there is nothing hinky gooing on in that department.Since i do not want to dismantle the thing im building i will rather snip 3 pins and put to bodges in instead of hoping that the pins are really NC.It does not add that much more work.When i have the composure to ask Worldsemi politely what they thought when they dit this, i will let you know what the reply is.Edit: Does someone have a tip for a LED driver from a different manufacturer?Around 18 Channels, 8 bit resolution, 20mA max current, 5V rail?Greeings,Peter

author: Mr.B
author_rank: Unknown
timestamp: January 26, 2016, 12:15:25 am
content: I have only used Omron W2RF002F before.24 channels.3.0V to 5.5V supply.Up to 50mA drive current per channel.Brightness is set at a 4 bit resolution which is translated into 1024 levels with built in fade algorithm to compensate for human eye response.Fade time is controlled by a further 5 bits of data.The chips are cascade-able for as many channels as you want.Specifically designed for RGB LEDs.A very capable chip indeed.However...It is bloody expensive.Datasheet attached.(I don't work for Omron.)

author: amyk
author_rank: Super Contributor
timestamp: January 26, 2016, 11:00:14 am
content: I guess the wirebonder was configured incorrectly, and instead of scrapping an entire batch of otherwise perfectly usable ICs, they just decided to change the documentation. I can see how easy it'd be to mix up the two pinouts for DIP/SOP (why would they be different anyway?) especially with the layout of those NCs.

author: wraper
author_rank: Unknown
timestamp: January 26, 2016, 11:09:39 am
content: Quote from: PeterFW on January 25, 2016, 10:44:54 pmNot difficult to check with more than 99% confidence. Just take one IC, connect all of the NC pins together and supply something like 100V on them (against GND pin). If there was no current flow and the chip is still alive, you have a winner.

author: PeterFW
author_rank: Frequent Contributor
timestamp: January 28, 2016, 01:06:14 am
content: Quote from: wraper on January 26, 2016, 11:09:39 amDit not think about dooing something like this, i will remember that for the future!The bodgeing and soldering of the 20 Chips went faster then i thought, still a major pain in the arse though.Quote from: amyk on January 26, 2016, 11:00:14 amWell... they still could have marked them somehow as differentGreetings,Peter