Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[zmix]

I have a multi channel "HD" named interface by a manufacturer I won't mention here by name which uses the AK5394 A/D converter chip.
The interface sounds very good, but the designer of the device used a tiny fan which makes a horrible racket in my studio. It is beyond annoying. The mfg claims that this is an unknown problem to them, yet the web is littered with angry complaints by users about the fan, one described it accurately as 'sitting next to a fish tank'.

I am currently experimenting with the device as follows: I have removed the fan and I have a temperature probe taped to the top of one of the converters, and I have the unit covered with a thick sweatshirt. Pretty adverse conditions.

The data sheet on the device lists a maximum ambient temperature as 70 celcius (158 Fahrenheit)

  http://www.asahi-kasei.co.jp/akm/en/product/ak5394a/ak5394a. html

My probe is currently showing that the temperature of the chip itself is around 61 celcius after the device was on for 14 hours, then covered with the heavy sweatshirt for two hours or so. Removing the shirt caused the device temperature to drop to 55C within 30 minutes and stabilize there. (the rack unit is fully closed, but unmounted and in a room which  is at 25C / 77F).


Questions:

How does the actual temperature reading of the device itself relate to the 'max ambient'temperature listed in the datasheet?

Am I pushing the design too much?

[rkulavik]

The Ambient Temperature of the AK5394A can go up 70C what this means is, that at infinitly close to the device but not touching it the air temperature can be as high as 70C.  The case in this condition will be much warmer than the air surrounding it.   You have measured a case temperature.  The case can get well above 70C without a problem.  

The numbers you quoted are more than fine for a case temperature of the AK5394A.  The goal of the part is to never exceed 125C die temp.  

The only problem you would run into with the fan being removed is that if the room or air around the box/part got to a point at which the thermal rise of the part got above 70C ambient.  Then you would be in trouble.  

Now this is only talking about my component, I have no knowledge of the rest of the parts in the box. Usually the regulators that power my device run our of room thermally before I do.  

A little known fact of the AK5394A is that it runs better warm.  At about 60C to 70C case temperature the part actually performs best.  

I hope this helps and again I can not talk of the box surviving only the AK5394A.

Regards,
Richard Kulavik
Manager of Marketing and Applications
AKM Semiconductor

[zmix]

Richard,
Thank you for the thorough reply to my question. I will continue monitoring the conditions of the device.

-CZ

[rkulavik]

Good luck with it.  

Regards,
Richard Kulavik
AKM Semiconductor

[zmix]

So far so good. The chassis seems to be no hotter without the fan and I can actually hear myself mix!!