RadioBanter - Frequency Division

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Carl R. Stevenson wrote:

Joe, I'd gladly use the Analog Devices DDS chips if they offered them in
something other than a SadoMasochistic Device (SMD) package. It's a darn
shame they can't make a limited run (say 10k) of some of these chips in a
PDIP package for hams and other r.f. experimenters.

That would be cost-prohibitive ... to tool up to make the parts in
obsolete packages that the production line is no longer using would
cost a fortune.

Absolutely right, Carl - it ain't gonna happen.

A very good article in 'Communications Quarterly' (RIP) explained how
the IC samples system works. Basically the economics of complex ICs are
the same as for developing a new drug - most of the selling price is
aimed at recovering the large upfront development costs. By comparison,
once the line is set up and rolling, the *production* cost of the actual
parts (or pills) is often quite minimal. It's a very good investment to
give away samples as bait, if they're going to help reel in orders for
large quantities.

Analog Devices (and also Maxim) are very clear that samples supplied to
amateurs are much less likely to bring in orders than those supplied to
commercial developers... yet they do it anyway, for the public good, and
because it doesn't cost them much. And we're very grateful for it.

But that's as far as their charity extends. As Carl says, nobody is ever
going to provide free samples of anything for which there's no
commercial market.

Frankly, it's also as far as charity to amateurs and other experimenters
*should* extend. They are not in business to featherbed us.

Fortunately, most amateurs have a "can do" attitude towards SMD. This
just arrived on another mailing list:

I broke my neck a few years ago and due to nerve damage my hands don't
work as well as they did but I was able to do the mod
[which involved SMD work on a $2000 transceiver]
without much trouble. I did it before the rig had even been on the
air, brand new out of the box, scary, yes but worth it.

I'm proud to be in the same ham community as that person.

--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)

http://www.ifwtech.co.uk/g3sek

"R J Carpenter" wrote in message
...

Read the latest QEX. The frequency synthesizer article contains hints on
soldering 0.6 mm spaced surface mount leads.

Thanks R J, I've already read it. Note the authors mention of the eyesight
and nerve
shattering problem of manually working with small SMD's. This is a hobby to
me; I have done my share of SMD soldering, and will do no more. If others
enjoy it, that's wonderful.
Now where did I put that ARC-5 I got to make a VFO for my Centeral
Electronics
10-B? :-)
73,
--
Chip
KC5UES
real e-mail address:

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Joe,
You seem to be under the impression that SMD's are "new". I obtained my
first "flat packs" in 1968. And they were surplus from some type of
computer, at that time. Sylvania made them - SUHL was the logic family of
these gates and flip-flops; I still have the two boards (less two or three
ic's I pulled off to play with) and the data sheets. The data sheets
indicate they were made in 1965 and 66.
They couldn't sell the package to anyone but military and commercial
customers (neither of which ever wants their boards to be "hackable") then
and the DIP became the standard for experimenters. Unfortunately, as you
alluded to earlier in this thread, there is not much of an electronic
tinkerer's market anymore. Now that more commercial apps. exist, the
manufacters can force what few tinkerers there are to accept the more
economical to produce SMD packages.
I readily admit that there are only a few options for experimenters when
the cold hard facts are faced.
1) gripe and cease building at the cutting edge of ic technology as I have
done;
2) buckle down and force oneself to say "SMD soldering is good for me- I
deserve it."(I'm sorry, I couldn't resist );
or 3) look for other options - Dave, Mike W, and you have made some good,
pertinent comments about daughterboards and adapters (a "Manhattan Style"
adapter with the ic soldered on would be just as useable as a DIP adapter -
if someone wants to take up Dave's challange.); just to prove that I'm not
the old stuck in my ways fart that some probably envision me as, I am
investigating DDS out a PCI or AGP slot of a pc (too bad video speed d/a
converters are unobtainable.) ;-).
May the hobby continue to grow and be fun for all who find it.

--
Chip
KC5UES
real e-mail address:

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"ChipS" wrote in message
...
I readily admit that there are only a few options for experimenters when
the cold hard facts are faced.
1) gripe and cease building at the cutting edge of ic technology as I have
done;

A loss - for you *and* for those who might benefit from the fruits of your
experimentation.

2) buckle down and force oneself to say "SMD soldering is good for me- I
deserve it."(I'm sorry, I couldn't resist );

I don't understand the "pain" aspect that folks keep citing ... I'm 53, "my
arms are
too short," and I've had corneal surgery that introduced some very irregular
astigmatism,
but I can still handle SMDs (at least down to 0403). Again, it's a matter
of learning
and using the proper techniques.

You need the following:

One of those adjustable lamps with the circular flourescent lamp and a
magnifier.
An eye loupe (10x) works well for me (for really close inspection).
A couple of small-tiped temperature-controlled soldering irons.
Some flux.
Some solder wick.
Some fine-tipped tweezers (almost needle pointed).
Fine guage solder (for use with the iron). Solder paste is best, though if
you're going to
do much SMD work ... I prefer the "no-clean" type with water soluble flux.

And, the best option, which I have, is a hot air reflow/rework station (I
bought one
brand new on eBay for $315 ... I also bought a "vacuum pen" which is the
easiest way
to pick up SMD parts and place them.)
Note that the hot air station and vacuum pen are NOT necessary to make SMD
work
painless - they are just niceties that I have chosen to invest in to make
the work even
faster and easier.

or 3) look for other options - Dave, Mike W, and you have made some good,
pertinent comments about daughterboards and adapters (a "Manhattan Style"
adapter with the ic soldered on would be just as useable as a DIP
adapter -
if someone wants to take up Dave's challange.); just to prove that I'm not
the old stuck in my ways fart that some probably envision me as, I am
investigating DDS out a PCI or AGP slot of a pc (too bad video speed d/a
converters are unobtainable.) ;-).

You start kludging all sorts of adaptor boards into the brew and you extend
lead lengths,
making it harder to get decent grounding and introducing all sorts of wierd
impedance
"bumps" - you can get away with it on audio and things that run at really
low clock rates,
but you're asking for trouble with RF or high-speed logic.

May the hobby continue to grow and be fun for all who find it.

Ah!!! Something we completely agree on :-)

73,
Carl - wk3c

In article , "ChipS"
writes:

Joe,
You seem to be under the impression that SMD's are "new". I obtained my
first "flat packs" in 1968. And they were surplus from some type of
computer, at that time. Sylvania made them - SUHL was the logic family of
these gates and flip-flops; I still have the two boards (less two or three
ic's I pulled off to play with) and the data sheets. The data sheets
indicate they were made in 1965 and 66.

Texas Instruments beat Sylvania by several years with DTL. :-)

I held my first flat pack (from TI), a single DTL flip-flop some time
in 1960. Couldn't believe how TI had managed to cram all that
circuitry in there! :-)

TI beat most of the competition with its introduction of TTL to
replace DTL. Their 7400 and 5400 part numbers have gone into
legacy mode for functional equivalents made by others since.
Those numbers are so common that some CMOS ICs have the
functional-equivalent numbers in their whole part number. :-)

They couldn't sell the package to anyone but military and commercial
customers (neither of which ever wants their boards to be "hackable") then
and the DIP became the standard for experimenters.

The original flat packs were excellent for stacking one on top of the
other in microwelded assemblies for spacecraft. JPL and one maker
of diallyl phthalate plastic holders came up with a kind of "super DIP"
that took the flat packs and etched-copper-foil-on-kapton-film as the
interconnect wiring.

The enemy of the flat packs and first ICs was CO$T. TI and every-
one else had to recoup their ramp-up and development costs and
almost shot themselves doing that. The single DTL flip-flop I held in
1960 cost $24 each! It was cheaper for the mainframe computer
makers to use discrete bipolar circuits than go to DTL and the flat
packs or even to TTL in flat packs. The big break was the
convenience of the dual-inline package and standardization on the
early 0.1 inch layout grid.

It's difficult to hack out welded-in-place flat packs. Many were so
mounted on flat PCBs back before wave-soldering was practical.

A big, big break for hobbyists was RTL from Fairchild. In little round
epoxy bipolar-size packages, those were affordable across the shelf.
My first frequency counter was built from Resistor-Transistor-Logic
back in 1968-1969. Cost was prohibitive then to go for TTL in the
new DIPs. Problem was that TTL out-performed RTL in speed and
ability to progress from SSI to MSI even in the old, original TTL
medium-speed family. Once 54H and 74H appeared, RTL was a
goner. Mainframe and minicomputer designs standardized on TTL
(to TI's delight, no doubt) and the other industrial applications picked
up on that. TTL prices dropped. Even more when the 74LS family
appeared with PDIP. 74LS became the family of choice for the first
microcomputers' "glue" holding them together circuit-wise.

Unfortunately, as you
alluded to earlier in this thread, there is not much of an electronic
tinkerer's market anymore.

I disagree. All kinds of electronic tinkerer's suppliers in certain
chain stores (Fry's Electronics in the southwest US has one whole
aisle for packaged ICs) and many small mail-order dealers as well
as the biggies such as Digi-Key, Mouser, and Newark. Legacy
ICs, especially logic, is down to well under $1 per package in
singles.

Now that more commercial apps. exist, the
manufacters can force what few tinkerers there are to accept the more
economical to produce SMD packages.

Disagree again. SMT is not necessarily "more economical to produce"
compared to DIP. The process is about the same. The driving force is
FINISHED ELECTRONIC SYSTEM SIZE and the consumer electronics
MARKETPLACE.

Industry estimates put cellular telephones (little two-way 1 GHz radios)
at about 3 Billion worldwide. In the USA alone in 2002, the U.S.
Bureau of Census stated that there were about 100 Million cell phone
subscribers, or roughly one out of three citizens with those tiny "HTs".
Cell phones are complex things and are appearing with more and
more auxilliary features...the only way to stay in the cell phone market
is to make them small and with tiny parts to cram everything in there.

I just replaced the thermostat in my house with a name-brand all-
electronic unit having a little LCD indicator (very easy to read,
momentary back light) and electronic thermal sensor, battery
powered so it won't lose its settings plus several other perqs not
possible with the 40-year-old bimetallic strip model. Neat little
SMT PCB, no crowding of anything. It is less than half the size of
the old one yet has more features.

The MARKET drives certain things, especially so in consumer
electronics.

I readily admit that there are only a few options for experimenters when
the cold hard facts are faced.

I don't. Looking back over more than a half century of electronics
hobby activity the options are FAR more NOW than back then. It's
been growing and branching out all that time.

The "cold hard facts" for SOME "experimenters" is that they can't
adapt to using semi-discrete ICs in readily-available DIPs but want
an all-purpose IC to do the DDS functional dirty work. The heart of
a DDS is basically a curious accumulator that must work in a
flexible way (several variations on the theme)...that is different than
the PLL counter which is just a preset-by-external-control to a fixed
countdown. Both share a phase-frequency "detector" (logic circuit)
which can be one of two general kinds. The DDS principle is vastly
different because of that flexible accumulator and hard to grasp for
most folks (took me a long while to get comfortable with it). It takes
more wiring in discrete logic than a PLL but both the DDS and PLL
can be done that way. "Experimenters" don't always need ultra-
small-sized sub-systems for frequency control.

Analog Devices (and some others) have collapsed most of the
frequency control sub-system into a single IC. We should ignore
the package size and be grateful that one IC saves a lot of discrete
packages and wiring. ADI's manufacturing choices are basically
market-driven, not "experimenter" driven. There's no guarantee that
every ADI IC model will survive in the near future...just like all those
other "legacy" ICs, mostly analog, of two and three decades ago
that aren't made now. Of about 8 variations of a MOS PLL IC that
Motorola made a decade ago (MC145nnn family), only one survives
today, the MC145151. Motorola couldn't sustain the cost of
continuing to produce something that didn't sell. [Motorola semi
split also, but that's another story]

1) gripe and cease building at the cutting edge of ic technology as I have
done;

"Cutting edge technology" doesn't require smallness. FUNCTION is
the cutting edge. A 5" x 8" PCB DDS made with ordinary logic ICs
has the same function as a 1" x 1" area on a PCB done with 1 IC.

2) buckle down and force oneself to say "SMD soldering is good for me- I
deserve it."(I'm sorry, I couldn't resist );

An HF-range frequency control sub-system can be made with legacy
digitial logic devices off-the-shelf in DIPs. If anyone insists on SMT
then they have to get that silly little millimeter soldering iron tip
and learn how solder in a small way...or, be inventive like a robotic
hobbyist who converted an ordinary toaster-oven into a reflow oven
for soldering 60-contact ICs with toothpick-applied solder paste.

Whichever way the construction is done, the prime driver is still
FUNCTION.

or 3) look for other options - Dave, Mike W, and you have made some good,
pertinent comments about daughterboards and adapters (a "Manhattan Style"
adapter with the ic soldered on would be just as useable as a DIP adapter -
if someone wants to take up Dave's challange.); just to prove that I'm not
the old stuck in my ways fart that some probably envision me as, I am
investigating DDS out a PCI or AGP slot of a pc (too bad video speed d/a
converters are unobtainable.) ;-).

"Video speed" D-to-A converters are available. Off the shelf. There's
at least three in every HDTV receiver today. :-)

May the hobby continue to grow and be fun for all who find it.

Heartily AGREE on that!

Len Anderson
retired (from regular hours) electronic engineer person

In article , Carl R. Stevenson
writes
An eye loupe (10x) works well for me (for really close inspection).
I used to have a magnifier that fitted over my glasses but stood forward
by 5 cm or so, this enabled focussing with magnification at a greater
distance in a narrow field , Ive lost it and have hand made another do
others use these.
--
ddwyer