[hpsdr] LPU internal 12V feedthrough connectors

[Scott Cowling]

Hi Luke,

The LPU is fabricated with 1 oz copper on the two layers. The trace 
between the two power-poles is 0.1" (2.54mm) wide.  For a 20C 
temperature rise, the maximum continuous current rating is about 6.5A.

For peak current calculations, the trace is about 45mm long and 
2.54mm wide, with a resistance of 9.4 milli-Ohms. At 18A, you will 
get about a 170mV drop in the trace resistance. More importantly, you 
could get excessive heating in the trace, depending on your average current.

You won't have trace-width limitations on the -V since it uses a 
plane for interconnect. However, the thermal reliefs, while very 
short, are pretty narrow.

My recommendation is that you add an external wire in parallel with 
the trace/plane between both the +V and -V power-pole terminals.

The power-poles themselves are rated for 45A, so they should not be a problem.

Good luck, and let us know how it works out!

73,
Scotty WA2DFI

At 09:17 2010-07-05 +1000, Luke Steele wrote:
>***** High Performance Software Defined Radio Discussion List *****
>
>Hi All,
>I am building an HPSDR system consisting of:
>- Atlas
>- LPU
>- Magister
>- Mercury
>- Penelope
>
>Also in the Pandora enclosure, I have mounted a Codan 100 W PA, which has
>low pass filtering on board.
>
>I am intending to install and use the LPU internal Powerpole connectors to
>power the PA, which has a supply specification of 13.8 V @ 18 A peak.
>
>My question is: Should I assume the +13.8 V pass through PCB track is
>adequate for the peak current required by the PA, or should I strap the +ve
>(and maybe also the -ve) terminals with an additional conductor? I have
>retained the breakoff strip for the Molex pins for the ATX connector.
>
>All going well, to this stage.
>
>Thanks,
>Luke VK3HJ
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