Buck converter minimum operating temperature

Thread Starter

Tony Wright

Joined Mar 18, 2019
2
I am an electronics novice and am looking for a 12V/5V converter that is proven to operate down to -25C. I want to power several security cameras that need to keep working during a Canadian winter. Most of the ones I have found on Amazon and Ebay claim -40C minimum but a reviewer has stated that one of these would not "switch on" below -20C. I contacted Drok (the Amazon supplier) who said the -40C was a mistake and -20C is the minimum. Many of these converters look alike with different names on them so who knows who makes them, they may be all the same but most claim -40C.
I want to distribute at 12V with converters at each camera but I suppose I could install a single larger converter and distribute at 5V, however the converter would still be subject to -25C

Any suggestions about suitable converters?

Thanks
Tony
 

Uilnaydar

Joined Jan 30, 2008
118
I play around with alot of those cheap Amazon/Ebay converters. Those environmental specs are suspect to say the least. If you REALLY need to operate at -25C or below. Head to a Digikey/Newark/Mouser company and pay the extra for an open frame DC/DC.

From Amazon, I've done OK with Meanwell... just look VERY CLOSELY at the labeling before using them at extremes. I've been burned by counterfeits before. For extreme conditions I get my Meanwell parts from Digikey.
 

ArakelTheDragon

Joined Nov 18, 2016
1,264
If they say -40, they will be ok until -30. Every converter should have a few grades of temperature. It can be produced for Automotive/Industrial/Military. Check the datasheet for which are possible. I think LM2596 is good.
 

Thread Starter

Tony Wright

Joined Mar 18, 2019
2
Thanks for the suggestions.

My project is a solar powered security camera system with five cameras outside and the solar controller/batteries in an unheated shed. I have already bought the cameras that run on 5V assuming it would be a simple matter to put a small 12V/5V converter ahead of each camera either outside (if they were waterproof) or in a small vented box. I then heard of a possible -20C temperature limit which is not low enough for southern Ontario. The max distance from the 12V batteries to camera is about 100ft so I am reluctant to run 5V wires from the shed because I don't know how the cameras will react to variable voltages. This means a central open frame converter is not really practical.

I think I am simply going to get what appear to be better quality converters with good reviews that claim -40C minimum (some say -20C).
Can someone explain what is meant by the following statement that I see on some data sheets.
"Operating temperature: -20 °c to +60 °c (Industrial grade), -40 °c to 80 °c (limit) "

Thanks
Tony
 

pmd34

Joined Feb 22, 2014
416
I think it means that the industrial grade components will operate "happily" from -20 to +60... but an odd case of -40 to 80 is OK but not suitable for continuous operations. A bit like the maximum voltage ratings of a component - "it shouldn't self destruct but we dont recommend you run it at this."
 

Yaakov

Joined Jan 27, 2019
1,604
Thanks for the suggestions.

My project is a solar powered security camera system with five cameras outside and the solar controller/batteries in an unheated shed. I have already bought the cameras that run on 5V assuming it would be a simple matter to put a small 12V/5V converter ahead of each camera either outside (if they were waterproof) or in a small vented box. I then heard of a possible -20C temperature limit which is not low enough for southern Ontario. The max distance from the 12V batteries to camera is about 100ft so I am reluctant to run 5V wires from the shed because I don't know how the cameras will react to variable voltages. This means a central open frame converter is not really practical.

I think I am simply going to get what appear to be better quality converters with good reviews that claim -40C minimum (some say -20C).
Can someone explain what is meant by the following statement that I see on some data sheets.
"Operating temperature: -20 °c to +60 °c (Industrial grade), -40 °c to 80 °c (limit) "

Thanks
Tony
Perhaps you can use a buck converter to get the 12V down to ~7V and linear regulators at each camera.
 

kubeek

Joined Sep 20, 2005
5,629
I think it means that the industrial grade components will operate "happily" from -20 to +60... but an odd case of -40 to 80 is OK but not suitable for continuous operations. A bit like the maximum voltage ratings of a component - "it shouldn't self destruct but we dont recommend you run it at this."
Not really, most stuff that is rated -20 will have trouble starting and operating at -40. At low temperatures usually things like oscillator not starting happen, but it should not have an effect on reliability or destruction of the device.
 
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