Maker Pro
Maker Pro

RF Coils SMT or Home Brew

X

Xanax

Jan 1, 1970
0
Hi all,
I'm building some rf pre-amps but have one or two problems.

Should I use SMT inductors or Coil inductors in my tank circuit?
I used SMT before and it gave unexpected results!

Cheers,
Xanan
 
P

Paul Burridge

Jan 1, 1970
0
Hi all,
I'm building some rf pre-amps but have one or two problems.

Should I use SMT inductors or Coil inductors in my tank circuit?
I used SMT before and it gave unexpected results!

What Q do you need? All the SMD inductors I've come across only manage
about 10 at most.
 
X

Xanax

Jan 1, 1970
0
I didn't know that the max Q was 10.
I would have tried to get a pretty hi Q of ~20.
Hummm...
Maybe home brew might be the man for the job.
Paul Burridge said:
Hi all,
I'm building some rf pre-amps but have one or two problems.

Should I use SMT inductors or Coil inductors in my tank circuit?
I used SMT before and it gave unexpected results!

What Q do you need? All the SMD inductors I've come across only manage
about 10 at most.
--

"Windows [n.], A thirty-two bit extension and GUI shell to a sixteen bit patch
to an eight bit operating system originally coded for a four bit
microprocessor and produced by a two bit company."
 
G

gwhite

Jan 1, 1970
0
Xanax said:
Hi all,
I'm building some rf pre-amps but have one or two problems.

Should I use SMT inductors or Coil inductors in my tank circuit?

How would I know? You should use whatever you determine to be the best
compromise between the inevitable conflicting demands. Coilcraft makes "spring"
coils that are smt.


Start here for ww smt coils:

http://www.coi1craft.com/smind.cfm

http://12.9.181.228/ProductFinder/index.cfm?fuseaction=ProductFinder.Main&CategoryID=1451

http://www.gowanda.com/index_surfacemount.asp

http://www.delta.com.tw/products/chipinductor/wire.htm

http://www.fastron.de/fastron_usa.html (http://www.stetco.com/)

I used SMT before and it gave unexpected results!

Maybe you don't know what you're doing.
 
I

Ian Buckner

Jan 1, 1970
0
Paul Burridge said:
Hi all,
I'm building some rf pre-amps but have one or two problems.

Should I use SMT inductors or Coil inductors in my tank circuit?
I used SMT before and it gave unexpected results!

What Q do you need? All the SMD inductors I've come across only manage
about 10 at most.
--

"Windows [n.], A thirty-two bit extension and GUI shell to a sixteen bit patch
to an eight bit operating system originally coded for a four bit
microprocessor and produced by a two bit company."

SMD inductor Q factors can be _waaay_ higher than that.

As an example, look at the CoilCraft SM "spring" inductors. If you
need
physically smaller they also do 1008HQ parts with peak Q's of 80-110.
At lower frequencies different ranges are better. Other manufacturers
are also out there.

Regards
Ian
 
A

Active8

Jan 1, 1970
0
SMD inductor Q factors can be _waaay_ higher than that.

so i was gonna say...
As an example, look at the CoilCraft SM "spring" inductors. If you
need
physically smaller they also do 1008HQ parts with peak Q's of 80-110.
At lower frequencies different ranges are better. Other manufacturers
are also out there.

0604HQ High Q Chip Inductors
Inductance values from 1.15 to 10.4 nH
Exceptionally high Q - up to 178 at 1.7 GHz!
Very high self-resonant frequencies - up to 12.3 GHz

mike
 
T

Tim Shoppa

Jan 1, 1970
0
Xanax said:
Hi all,
I'm building some rf pre-amps but have one or two problems.

Should I use SMT inductors or Coil inductors in my tank circuit?
I used SMT before and it gave unexpected results!

SMT's can work fine. Just like non-SMT inductors, there's a wide range
of types to choose from. Choose the wrong kind and it won't work well
(probably your previous experience).

For starters: what sort of Q (probably highish given that it's a tank circuit),
what sort of inductance (uH? nH?), what frequency region (MHz? GHz?) do
you need?

Tim.
 
Top