EMRFD Message Archive 1387

Message Date From Subject
1387 2008-02-01 16:07:48 Clark Fishman WANTED MC145152 Freq synthesizer Chips
I have used the MC145152 before and although it ain't being may any more I would like to lay my hands on several for some projects I am working on.

If anybody knows of another parallel programmed dual modulus (or if the freq range is high enough ,single modulus) replacement please let me know.

Clark Fishman WA2UNN QRP and RF designer

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1388 2008-02-01 18:37:39 kerrypwr Re: WANTED MC145152 Freq synthesizer Chips
1407 2008-02-05 03:43:36 wa7mlh Re: WANTED MC145152 Freq synthesizer Chips
I used the MC145152 back in the late 1990s in a VHF synth.
They were rather expensive and it took little to static zap one of the
few I had. The only benefit of the 145152 is that you can control it
with with manual parallel loading via switches.

Since then I found that the MC145175 is a really nice alternative.
It does require a 3 wire serial bus to program the registers, but that
turned out to be rather straight forward with a PIC 16F84.

Most of the Motorola VHF PLLs were discontinued a number of years ago
except for the 145175, but they took a long time to drop them off
their online catalog. The distributors I talked to were clueless about
availability when pressed to deliver.

My present interest is the Analog Devices PLLs.
They have an architecture very similar to the Moto versions, yet seem
easier to understand (In my mind).
I have not fired up my AD PLLs yet but will hopefully do that soon.

The programming function was rather straight forward for me after I
got a PIC programmer from a Colorado outfit called microengineering

These folks have some awesome PIC related products and great prices.
I can not recommend them enough.

I got their EPIC kit ($60) and it was a wonderful way to get control
of the PLL. The EPIC programmer runs off the parallel port in Windows
and is done in BASIC with some really nice code function features. I
liked the BASIC idea since I was not too motivated to learn C, which
seems to be the predominant language for a lot of the small RISC CPUs.

Another advantage of going with a PIC is that so many of them have
EEPROM so you can make the PIC/PLL remember where to start or to
remember where it was when it turned off.

Another advantage of the PIC serial control is that, if you plan
things ahead properly, you can dedicate 3 pins for control and use
another 3 pins to connect between the PIC and the PLL. This allows you
to put the PLL in to the circuit, leave it pulgged in to the circuit,
and then plug in a 3 pin Berg connector for programming and then pull
the plug after you like what you have done in terms of code. Leaving 3
Berg pins on the PLL board allows you to do code mods later without
ever needing to take the PIC out of the PLL system.

A PIC also allows an almost endless number of ways to drive the PLL
after the total system interface is determined. It can listen to push
button switches and/or a keypad and/or Gray code shaft encoder and
even a potentiometer. It can even be the interface for the option to
drive it from a laptop/PC.

These features are really a bit much to try and do with a parallel fed
PLL like the 145152.

Hope this is helpful.

1408 2008-02-05 04:48:49 sm5glc Re: WANTED MC145152 Freq synthesizer Chips
Sometimes you simply do not want a micro processor in your circuit for
what ever reason. The 145151/2 did a good job, and I have used it in
several designs. Plessey had some neat chips too, i.e. NJ8820 which
could be controlled by a PROM. Used these to phase lock x-tal
oscillators of odd frequecies to a 10 MHz ref.

Later on Qualcomm had the Q3036 which was great with boht serial and
parallell control. Peregrine Semi did offer a low-power higher spec
version, the PE3236 which is still available but at a rather steep
price ~$25-30. These are great when you need high reference frequency.
One could build a rather neat synth with a DDS and one of these for
coarse tuning. BTW Qualcom had some nice application notes
1409 2008-02-05 05:42:59 John Levreault Re: WANTED MC145152 Freq synthesizer Chips
FWIW, there's an article in the Jan/Feb08 QEX on a 2256MHz LO design. It
uses the National LMX2326 PLL driven by a PIC16F84. The associated files
are downloadable from www.arrl.org/qexfiles. The file name is
1x08_Kocsis.zip. He runs the PIC at 85Hz (!) to keep the noise down. The
combo of a modern PLL chip and a PIC looked pretty simple, even for an
aging analog guy like myself. The PLL was designed with the on-line
simulator at national.com.

73 de John NB1I