MC12148

A

Active8

Guest
JT mentioned this chip the other day. At first, I thought it was an
older chip, but the long part number rang a bell and sure enough, I
got a few samples of these about 10 yrs ago when the spec was still
stamped "Advance Information."

The spec at that time implied that the trick was to find high Q tank
components and it said that Motorola was working on that ( :) like a
new engine that runs on a fuel yet to be developed.)

I never had a chance to play with the chips much. What would a
designer do for tank components for this VCO if he were shooting for
close to 1GHz? I might've went for a coaxial resonator, but that
precludes voltage control unless an added varactor could be used to
vary the freq.

Did On Semi pick up this chip from the Mosaic line, or is it
history?
--
Best Regards,
Mike
 
Active8 wrote:

JT mentioned this chip the other day. At first, I thought it was an
older chip, but the long part number rang a bell and sure enough, I
got a few samples of these about 10 yrs ago when the spec was still
stamped "Advance Information."

The spec at that time implied that the trick was to find high Q tank
components and it said that Motorola was working on that ( :) like a
new engine that runs on a fuel yet to be developed.)

I never had a chance to play with the chips much. What would a
designer do for tank components for this VCO if he were shooting for
close to 1GHz? I might've went for a coaxial resonator, but that
precludes voltage control unless an added varactor could be used to
vary the freq.

Did On Semi pick up this chip from the Mosaic line, or is it
history?
Click to expand...
ON semi carries the MC100EL1648, if that's a long enough part number for
you. Says it goes up to 1.1GHz.

I remember reading in Microwaves & RF about short coaxial resonators
built by silver plating a high-dielectric constant ceramic, for this
sort of frequency range. I have no idea who would make them, and it was
about 15 years ago.

Might want to try MuRata; I'm not sure who else does that sort of thing
any more.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com
 
"Active8" <reply2group@ndbbm.net> wrote in message
news:1xb0cfweurfk7$.dlg@news.individual.net...
JT mentioned this chip the other day. At first, I thought it was an
older chip, but the long part number rang a bell and sure enough, I
got a few samples of these about 10 yrs ago when the spec was still
stamped "Advance Information."

The spec at that time implied that the trick was to find high Q tank
components and it said that Motorola was working on that ( :) like a
new engine that runs on a fuel yet to be developed.)

I never had a chance to play with the chips much. What would a
designer do for tank components for this VCO if he were shooting for
close to 1GHz? I might've went for a coaxial resonator, but that
precludes voltage control unless an added varactor could be used to
vary the freq.

Did On Semi pick up this chip from the Mosaic line, or is it
history?
--
Best Regards,
Mike
Click to expand...
In the Motorola spec sheet (1997, Rev 5) it says:

Tank Component Suppliers

Below are suppliers who manufacture tuning varactors and inductors which can
be used to build an external tank circuit. Motorola has used these varactors
and inductors for evaluation purposes, however, there are other vendors who
manufacture similar products.

Coilcraft Inductors A01T thru A05T
Coilcraft-Coilcraft, Inc.
1102 Silver Lake Rd.
Gary, Illinois 60013
708-639-6400

Loral Tuning Varactors GC1500 Series
Loral
16 Maple Road
Chelmsford, Massachusetts 01824
508-256-8101 or 508-256-4113

Alpha Tuning Diodes DVH6730 Series
Alpha Semiconductor Devices Division
20 Sylvan Road
Woburn, MA 01801
617-935-5150

* At 1.1 GHz, use a Coilcraft A0IT Springair coil at 2.5 nH and a Loral
Varactor 3.0 to 8.0 pF at VIN = 1.0 to 5.0 V.


I hope this helps.

John
 
On Fri, 05 Nov 2004 03:56:22 GMT, John Smith wrote:
<snip>
* At 1.1 GHz, use a Coilcraft A0IT Springair coil at 2.5 nH and a Loral
Varactor 3.0 to 8.0 pF at VIN = 1.0 to 5.0 V.

I hope this helps.

Best tip I've seen. The advanced info had non of that.
Click to expand...

Thanks
--
Best Regards,
Mike
 
On Thu, 4 Nov 2004 15:44:10 -0500, Active8 <reply2group@ndbbm.net>
wrote:

JT mentioned this chip the other day. At first, I thought it was an
older chip, but the long part number rang a bell and sure enough, I
got a few samples of these about 10 yrs ago when the spec was still
stamped "Advance Information."

The spec at that time implied that the trick was to find high Q tank
components and it said that Motorola was working on that ( :) like a
new engine that runs on a fuel yet to be developed.)

I never had a chance to play with the chips much. What would a
designer do for tank components for this VCO if he were shooting for
close to 1GHz? I might've went for a coaxial resonator, but that
precludes voltage control unless an added varactor could be used to
vary the freq.

Did On Semi pick up this chip from the Mosaic line, or is it
history?
Click to expand...
The MC12148 is simply my old MC1648 design done in MOSAIC.

I don't know if you can rig it to run on a coaxial resonator or not.

I _think_ it can still be purchased from Lansdale.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
 
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