Low noise swithching supplies

[Richard Hosking]

Begging your indulgence again, learned gentlemen...

I am looking again at a Tayloe Rx (that's why the 74ACT163 /4 counter etc)

Using DDS and various level shifting circuits for logic, need negative
supplies for opamps etc
I want max efficiency for a portable unit so looking at switching regulators
Obviously keen to keep RF noise to a minimum
Devices would need to be available in small MOQ and reasonably cheap

What solutions would you use for +8V, +5V, +3.3V, +1.8V, -8V, all from 12V?
What shielding, filtering etc would be required?

Grateful for pointers

Thanks
Richard

 

[PeteS]

Begging your indulgence again, learned gentlemen...

I am looking again at a Tayloe Rx (that's why the 74ACT163 /4 counter etc)

Using DDS and various level shifting circuits for logic, need negative
supplies for opamps etc
I want max efficiency for a portable unit so looking at switching regulators
Obviously keen to keep RF noise to a minimum
Devices would need to be available in small MOQ and reasonably cheap

What solutions would you use for +8V, +5V, +3.3V, +1.8V, -8V, all from 12V?
What shielding, filtering etc would be required?

Grateful for pointers

Thanks
Richard

What current is required out of each of those supplies (peak and
average)?

Cheers

PeteS

 

[Richard Hosking]

None to exceed 200mA, the greatest will be the 1.8V supply. The 3.3V and
5V will be of the order of 50mA max

Richard

 

[[email protected]]

Begging your indulgence again, learned gentlemen...

I am looking again at a Tayloe Rx (that's why the 74ACT163 /4 counter etc)

Tayloe? Ah, a switched-capacitor RF detector:
http://www.hanssummers.com/electronics/gallery/4/ ... cool.

Using DDS and various level shifting circuits for logic, need negative
supplies for opamps etc
I want max efficiency for a portable unit so looking at switching regulators
Obviously keen to keep RF noise to a minimum
Devices would need to be available in small MOQ and reasonably cheap

What solutions would you use for +8V, +5V, +3.3V, +1.8V, -8V, all from 12V?
What shielding, filtering etc would be required?

Might consider synchronizing the switchers to the VFO, suitably
scaled, thereby zero-beating any switcher noise.

The switcher itself, of course, needs shielded magnetics, and a
shielded box.

Grateful for pointers

Thanks
Richard

Regards,
James Arthur