How to source a display driver chip? ST7781R - Page 1
Forum section: electronics / general

author: rwgast_lowlevellogicdesin
author_rank: Frequent Contributor
timestamp: May 11, 2015, 04:51:27 am
content: So I got a few 2.8 inch touch screen Seed Studio LCD "shields" @ RadioShack on clearance for 15 bucks a pop!! thought this was a rather good deal for a module which is has a user base and documentation. My issue is If im going to prototype with these modules I would like to know I can build products out of them later. The display chip is a Sitronix ST7781R, Im not seeing these on digikey or mouser! Does this mean it will be a huge PITA to source these chips in small quantity's?? I cant even find an option to purchase on the Sitronix site!

author: andersm
author_rank: Super Contributor
timestamp: May 11, 2015, 05:39:36 am
content: I don't think these are the types of chips you buy unless you're a display module manufacturer. If you're having trouble sourcing displays using that controller, contact Sitronix to see if they have a compatible replacement. These types of chips are often very similar to each other, so you may also find a compatible part from another manufacturer.

author: kripton2035
author_rank: Super Contributor
timestamp: May 11, 2015, 05:45:26 am
content: for sure it will be cheaper to change the whole display unit with the chip inside, than change the only chip by yourself.

author: rwgast_lowlevellogicdesin
author_rank: Frequent Contributor
timestamp: May 11, 2015, 07:16:17 am
content: So basically im going to have to source a whole lcd unit using this chip or similar model I cant just go out and get a compatible lcd and the chips to make my own custom projects in volume? I dont want to learn the ins and outs of the chip at register level if these discontinued screens that are usually 40 bucks are either A 49 bucks, or B hard to track down.

author: andersm
author_rank: Super Contributor
timestamp: May 11, 2015, 08:21:46 am
content: If you have the necessary volumes and production means I guess you could manufacture your own, but not to sound too snooty, if you did you wouldn't be asking about it here. Usually you just contact the display module manufacturer directly. You won't be paying Radio Shack prices unless you make a spectacularly bad deal.

author: Jeroen3
author_rank: Super Contributor
timestamp: May 11, 2015, 08:26:35 am
content: The LCD controller is often molded into the flat-cable of LCD panel itself, making the LCD panel and controller a inseparable pair.

author: wraper
author_rank: Unknown
timestamp: May 11, 2015, 08:40:59 am
content: This is controller for the chip on glass displays. What are you going to do with bare dies?

author: picandmix
author_rank: Frequent Contributor
timestamp: May 11, 2015, 08:41:29 am
content: Sounds all wrong to me, never heard of anyone making up their own lcd from a separate chip and display on a small volume production basis.As already said they are classed as 'sealed units'. When the unit fails you bang in a compete new unit, simply not practical to effect repair.You can contact Sitronix direct and they will probably accept your order for those chips, but be aware, like most manufacturers they will have a minimum order quantity, typically 10,000 at least.Many lcd screens come and go very quickly, though a few do seem to stand the test of time.It would be a much better approach if you designed your hardware and software to be more flexible and allow you to easily upgrade to newer displays as the lcd market progresses.