The Murata is not a good choice for most. ?It's called a "linear regulator replacement", actually a buck mode switcher. ?Would supply 5v to the Raduino at about twice the efficiency of our LM7805 (so worth looking into if you are running off of batteries), but likely produces a fair bit of radio noise unless well shielded and with appropriate bypass caps and fillters.
I have unsoldered the LM7805 from my raduino and installed one by laying it flat on the back side of the board. ?The tab of the LM7805 can be ground, I have soldered mine to the copper ground plane on the back side of the Raduino.to better distribute any heat. ? It's the tab of the IRF510 that cannot touch ground, it's typically up around 12vdc while transmitting, and will have lots of RF riding on top of that.
Jerry, KE7ER
toggle quoted message
Show quoted text
On Mon, Jun 12, 2017 at 08:43 am, Geoff Lowe wrote:
first off, thanks to everyone in the Bitx community for their advice and input on improving the design and functioning of the Bitx40.
Has anyone looked into replacing the 7805 with a Murata linear supply like this one: ? I've used this in a few other applications and it runs very cool, even with 15+VDC input. It's a pin-for-pin replacement to the 7805 except the pins are in the reverse order.
The case I have places the VR and heat sink very close to the metal side and I thought that if it gets hot or bumped the heat sink will short to the case, something Ashar says is a no-no! Replacing the VR with the linear unit should cut down on the heat generated, plus a plastic film on the case by the heat sink will prevent the short, without worrying about the heat dislodging the plastic film.
Thanks.
?
