Managing heat in tight circuits

[Technova]

You know those projects where everything is packed in so closely that the heat just builds up? Chips running hot, traces squished together, and components all vying for a bit of airflow. Some people are all about those smart layouts, while others rely on cooling solutions like heatsinks or fans.

What strategies have you found most effective for keeping things cool in compact circuits?

 

[Sony77]

Totally! In tight setups, heat builds up fast—keeping hot components like regulators away from sensitive ones (like the Sensitive Sound Detection KY-037), adding tiny heatsinks, and allowing even a bit of airflow makes a big difference.

 

[barfle]

Judicious use of heat sinks is part of circuit design! Along with avoiding parasitic capacitances, etc., it’s an element that needs to be addressed.

When I was first starting out in electronics, I was building circuits designed by engineers (definitely not me!). I got a project that had probably 100 reed relays, and a box to fit them into. I made several vectorboard “pages” that had all the interconnect wiring on one side, like the pages of a book, and it all fit in the box it was supposed to. The engineer seemed unhappy with me when it got hot and started to smell. Hmmm, who’s job was thermal management?

 

[Alan]

Yeah, compact builds can really heat up quickly. I've seen some clever layouts with copper pours work wonders, but honestly, just having a mini heatsink in the right spot or ensuring there's a good airflow path can make a huge difference. Really interested to hear what tips others here swear by.

 

[oldgeek]

Many years ago I was working on a pulse correlator that had a 400MHz clock with high speed RAM (back when 400MHz was considered blazing fast). The timing requirements were so tight that I stacked them four high, one directly on top of the other, with address, data and power all soldered directly to the chip beneath, only the chip selects bent out to attach a wire to. Everything had to be controlled impedance. This was the first time I had ever worked on a digital circuit where everything was a transmission line. But that's not why we're here. Heat was the big problem. I was pretty sure I would have temperature issues because these chips ran hot even without stacking them. There was no way I could heatsink the mess. fortunately it was a proof of concept, so my cooling solution was a bottle of dry nitrogen fanned out into a dozen small copper tubes, blowing the cold nitorgen directly onto the parts. They ran cool as a cucumber. The chief engineer just shook his head, but IT WORKED!

 

[Alan]

Many years ago I was working on a pulse correlator that had a 400MHz clock with high speed RAM (back when 400MHz was considered blazing fast). The timing requirements were so tight that I stacked them four high, one directly on top of the other, with address, data and power all soldered directly to the chip beneath, only the chip selects bent out to attach a wire to. Everything had to be controlled impedance. This was the first time I had ever worked on a digital circuit where everything was a transmission line. But that's not why we're here. Heat was the big problem. I was pretty sure I would have temperature issues because these chips ran hot even without stacking them. There was no way I could heatsink the mess. fortunately it was a proof of concept, so my cooling solution was a bottle of dry nitrogen fanned out into a dozen small copper tubes, blowing the cold nitorgen directly onto the parts. They ran cool as a cucumber. The chief engineer just shook his head, but IT WORKED!

That’s quite an impressive setup, and what a smart save. It really showcases proof-of-concept engineering at its best. Thanks for sharing this story!