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Re: Current consumption


 

There have been two major component changes in the QDX over the course of its availability that may affect its power consumption.

The first is the synthesizer chip. Version 1 used the Si5351A from Silicon Labs. Versions 2 and 3 use the MS5351M from Hangzhou Ruminang Tech, due to unavailability?of the SiLabs (now Skyworks) parts. According to a report, the MS5351M uses about 8mA more current than the Si5351A. Hans Summers reports that the MS5351M has slightly better phase noise performance.

The other is the audio codec. A different one is used in Version 3 because the one used in the previous versions was discontinued.

One other switch may have decreased current consumption slightly in versions 2 and 3. Version 1 had pullup resistors on some open collector outputs. In versions 2 and 3, those resistors are removed; instead, the firmware activates the on-chip pullups. Loading newer firmware on a version 1 board may increase power consumption a tad because both sets of pullups are active, though you can remove the unneeded resistors from the board if you want.

On Fri, Aug 12, 2022 at 10:52 AM Don DeGregori <ddegreg1@...> wrote:
I believe the early version of QDX used a different chip. When it became unavailable
because of world wide shortages, Hans had to change to a higher current substitute.
The QDX today draws about 140ma on RX, plus or minus 10ma.

Don

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