[hpsdr] Hot ADC

[Murray Lang]

I'll be putting a small fan near mine. Can't justify buying a 
replacement in the current environment.

BTW I understood the risks and happily accepted them. I think everything 
would grind to a halt if we were to apply strict a consumer protection 
mentality. All of the very generous and talented contributers would go 
back to their day jobs and we would have nothing.

Cheers,
Murray VK6HL

Dale Boresz wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
> Just another set of data points ...
>
> Using a small thermocouple, I measured 62 C on the top of the ADC, and 
> 66 C on the foil pad on the back of the board. Ambient temp in the 
> area of the boards is about 26 C. Measurements made after approx. 30 
> minutes of operation.
>
> Dale
> WA8SRA
>
>
> Philip Covington wrote:
>> ***** High Performance Software Defined Radio Discussion List *****
>>
>> On Tue, Jan 13, 2009 at 1:53 PM, Kjell Karlsen <la2ni at online.no> wrote:
>>  
>>> ***** High Performance Software Defined Radio Discussion List *****
>>>
>>> I do not have a thermometer to measure the temp of the ADC but it 
>>> felt very
>>> hot, much more than I liked. I glued a small Heatsink on top of the 
>>> chip and
>>> it helped a bit. When I had a look at the  aeria on the bottom of 
>>> the board
>>> directly under the chip, I discowered that the solder may not have 
>>> melted
>>> properly when the board was produced. There was no sign of solder up 
>>> in the
>>> holes below the ADC. I resoldered the aeria and now the bottom of 
>>> the card
>>> is warmer than before. Unfortunately I can not confirm this by 
>>> measurements,
>>> but my feeling is that the chip is colder now.
>>>
>>> Can someone do a tempereture measure before and after resoldering 
>>> and report
>>> back?
>>>
>>> Kjell
>>>     
>>
>> I have measured the LTC2208 ADC temperature of quite a few QS1R
>> receiver boards (this is done as part of the manufacturing tests).  If
>> the ADC is soldered properly, the average temperature on the top
>> surface of the ADC is around 54 C ( 130F ).  If it is considerably
>> higher than that it is usually because of inadequate soldering of the
>> thermal pad on the underside of the ADC.
>>
>> I don't know how the thermal pad is designed on the Mercury, but 70 C
>> ( 158F) is excessive, I'd think.
>>
>> Gluing a heatsink to the top of the ADC does not help much.  The heat
>> removal should be via the thermal pad through the PCB.
>>
>>   
>
> _______________________________________________
> HPSDR Discussion List
> To post msg: hpsdr at hpsdr.org
> Subscription help: http://lists.hpsdr.org/listinfo.cgi/hpsdr-hpsdr.org
> HPSDR web page: http://hpsdr.org
> Archives: http://lists.hpsdr.org/pipermail/hpsdr-hpsdr.org/
>


 1231895323.0