How much current each FPC connector can handle? - Page 1
Forum section: electronics / projects

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: May 28, 2020, 07:00:02 am
content: Hi,I have a product that needs 5V @1.2A and I should use these FPC connectors and Flat cables to power them, I just wonder how much current each pin can carry?https://lcsc.com/product-detail/FFC-FPC-Connectors_Made-in-China-FFCCable-FFCCable20Ppitch0-5mmlength8CM-In-the-same-direction_C122342.htmlhttps://lcsc.com/product-detail/FFC-FPC-Connectors_JUSHUO-AFC11-S20ICC-00_C11073.htmlAny Ideas or experience?

author: Berni
author_rank: Super Contributor
timestamp: May 28, 2020, 09:27:55 am
content: You can find FPC connectors rated for about half an amp per pin but i never felt comfortable with that.But something like 250mA per pin sounds about reasonable to me and is commonly used for powering LCD backlights from such 0.5mm pitch FPC strips.So yeah for 1.2A you will need quite a few pins.

author: dzid_
author_rank: Newbie
timestamp: December 12, 2024, 12:34:42 pm
content: This topic comes up on Google first regarding FPC current rating.I did some tests with the 0.5 pitch fpc ribbon.0.5A - Δ1°C1A - Δ7°C1.5A - Δ18C2A - Δ36CSurely the connector can handle 0.5A as well.And if one runs multiple power lines next to each other, the temperature rise is somewhat additive. It might be a good idea to insert ground in between signal lines anyway.The last thing to lookout for then is the voltage drop.

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: December 12, 2024, 02:09:47 pm
content: thanks for sharing! how long does it get to the 50C temp at how much current?

author: ajb
author_rank: Super Contributor
timestamp: December 12, 2024, 04:27:27 pm
content: Always cool to see some empirical dataQuote from: dzid_ on December 12, 2024, 12:34:42 pmUsing more conductors for a given amount of current will always be better, but it's worth noting that the allowable dissipationper conductorwould go down as the number of conductors used increases. As the temperature of the FPC/FFC goes up, so does the resistivity of the conductors, and therefore so does total dissipation. It's also harder to reject the increased amount of heat to the environment, so temperature rise will be increased anyway. The connector is of course a big variable, and I would expect contact temperature to be the main limiting factor in terms of thermal performance, since a failing contact can cascade rapidly. Ensuring that the power contacts have solid thermal connections to board copper can help there, but will probably not help much with cable temperature. Thermal limits like this can be hard to generalize -- just about any connector datasheet will warn you that their current ratings are guidelines and you should do your own engineering based on your application.

author: Berni
author_rank: Super Contributor
timestamp: December 13, 2024, 07:53:51 am
content: Very nice test there.From the thermal image is is clear the weakpoint is the resistance of the FPC traces. There doesn't seam to be any hotspots at the connector so it could in theory handle even more if you had a thicker FPC cable.But yeah contact resistance is not always perfect. So even if it might work in this case, it might not be reliable once you produce 100 such products and some of the pins oxidise or get dirty trough their lifetime.