Design for volume manufacture - cheapest solution for d-type flip flop - Page 1
Forum section: electronics / projects

author: Engineer1
author_rank: Contributor
timestamp: October 19, 2015, 03:50:35 pm
content: Hello,I'm designing a (consumer target market) product intended for volume manufacture (>10K units per year, possibly >100K units). It's got to be as cheap as possible to manufacture. The manufacturing cost for this product needs to be brutally low.I need a single D-type flip flop function, and want to ask what the recommended logic family would be for this application? Speed isn't remotely important (it's clocking at 50Hz)At this stage I have complete flexibility with the design, and could do it with discrete transistors, or gates, or a complete device (like a 74LVC1G80). The '1G80 is listed on TI's site at $0.06US in volumes of 1000. Is there a cheaper way? Do the Chinese (etc.) device manufacturers clone devices at this level? (I've been designing electronics professionally for 25 years, but at the other end of the market - medical products - low volume, high cost.)Any thoughts gratefully received.Thanks a lot.Steve.

author: Howardlong
author_rank: Super Contributor
timestamp: October 19, 2015, 04:26:10 pm
content: By the time you've placed enough discrete parts to do the same as the 74LVC1G80, I'd hazard a guess that the $0.06 has already been hit for the volume you're talking about.Difficult to recommend much without knowing more about what you're trying to achieve, what else is on the board, is it possible to design around it or integrate it into something else? At 50Hz, if there's an MCU on there the function could be achieved within that for example. What are the current total BOM and manufacturing costs, and what is the target price?[I'm not sure what your involvement is with the project, whether it's a contract designer or something more. If it's your baby, just take care not to rape yourself: it's all too easy to think you can make a living off, say, a $20 retail widget with a COGS of $15: you can't (if you live in the West at any rate).]

author: Engineer1
author_rank: Contributor
timestamp: October 20, 2015, 10:00:16 am
content: Thank you very much for that. Your advice matches my views. This is a design contract. The COGS target is <£5 GBP, with an expected retail of ~£20 GBP.There isn't an MCU - it's a really simple product, and there's no need for one. Having said that, it would be lovely to be able to solve all the design goals with one, but that would be lazy, and it can all be done with a few discrete parts, and some ingenuity!Thanks once again - I'll go with the '1G80.

author: westfw
author_rank: Super Contributor
timestamp: October 21, 2015, 09:47:43 am
content: you might want to check whether you can get cheaper "standard logic" chips (4013, 74hc74, etc) - more second soucres/etc than the single-gate packages.(the single-gate D flipflops were NOT the cheapest at digikey. OTOH, they didn't get down to $0.06 each, either.)

author: Engineer1
author_rank: Contributor
timestamp: October 21, 2015, 11:54:55 am
content: You may well be right. It's hard to easily get pricing information for clone devices, without going via Alibaba etc. I'm basing the choice on the pricing I can get from 'pucker' manufacturers. If I can hit the target price with them, then hopefully there will be extra scope to get the cost down, if necessary.On the TI site the '1G80 is the cheapest ($0.06US):http://www.ti.com/lsds/ti/logic/d-type-flip-flop-products.page#o4=ACTIVEAnd at Fairchild I can get even cheaper (NC7SZ374P6X - $0.0495US):https://www.fairchildsemi.com/products/logic/flip-flops-latches-registers/flip-flops/#N=4294961026+4294960859+4294921159+4294921155+4294921156+4294921152+4294921154&&Ns=P_Price|0&&showAll=false&&showHrd=falseThanks for taking the time to answer.

author: autobot
author_rank: Regular Contributor
timestamp: October 23, 2015, 12:05:41 am
content: Maybe you could integrate more components from the design inside a greenpak(from silego) , and do so more cheaply.

author: FrankBuss
author_rank: Unknown
timestamp: October 23, 2015, 01:40:26 am
content: Depends on your product, but if you need additional external parts, like resistors and capacitors for resetting the d flip flop on power up etc., costs for all parts and assembly costs could be higher than for one small PIC. And for 100k parts per year you can contact Microchip for a good price, including flashing the parts. And if you run into a problem with the d flip flop, like the customer wants an additional delay, or some debouncing problems, it is easy to change the firmware.

author: Gribo
author_rank: Frequent Contributor
timestamp: October 23, 2015, 07:35:08 am
content: Here (Israel) local assembly houses charge 0.04 to 0.01USD per SMD component, Assuming pricing is similar in your case, it is cheaper to use the '1G180 instead of a custom solution. Also, consider that board space, manufacturing and assembly time all contribute to the total cost. small runs hide those costs behind other fees (setups, masks etc).

author: nowlan
author_rank: Frequent Contributor
timestamp: October 23, 2015, 07:59:27 am
content: Just wondering about the GreenPak 2 mentioned before. The website says not recommended for new designs, but show no alternative?

author: deephaven
author_rank: Frequent Contributor
timestamp: October 23, 2015, 08:18:37 am
content: The NXP version of the chip seems a little cheaper. Put the number into findchips.com

author: autobot
author_rank: Regular Contributor
timestamp: October 23, 2015, 02:45:36 pm
content: There's are a a variety of greenpak versionsHere:http://www.silego.com/products/greenpak3.htmlalso under the product tab