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Old May 12th 04, 02:49 AM
Ken Scharf
 
Posts: n/a
Default DDS chips

For those trying to solder those TSSOP and TQFP AD
chips into a circuit I found this site on the net

http://aprilog.com/perl/main.pl

They sell adaptors to solder the chip onto to plug
into standard dip sockets.

There are other types of breadboard circuit boards
for these chips as well. Search on google for
"TSSOP breadboard" or "TQFP breadboard".

Now that I see it might be possible I'm going to try
and make use of those 9954 and 9851 chips I got as
samples. The 9932 looks interresting too, with it's
low power. I also want to get a sample of the 9834,
now THAT's a low power chip, perfect for QRP.

Anybody have any 'war stories' about using these DDS
chips in a rig as a vfo?
  #2   Report Post  
Old May 12th 04, 03:35 AM
W3JDR
 
Posts: n/a
Default

I think the problem with these is going to be placing the bypass caps close
enough to the chip, and also getting good low-impedance RF ground paths.
For just a little more money, you can buy an entire DDS board with all parts
from NJQRP.

Let us know how you make out.

Joe
W3JDR


"Ken Scharf" wrote in message
...
For those trying to solder those TSSOP and TQFP AD
chips into a circuit I found this site on the net

http://aprilog.com/perl/main.pl

They sell adaptors to solder the chip onto to plug
into standard dip sockets.

There are other types of breadboard circuit boards
for these chips as well. Search on google for
"TSSOP breadboard" or "TQFP breadboard".

Now that I see it might be possible I'm going to try
and make use of those 9954 and 9851 chips I got as
samples. The 9932 looks interresting too, with it's
low power. I also want to get a sample of the 9834,
now THAT's a low power chip, perfect for QRP.

Anybody have any 'war stories' about using these DDS
chips in a rig as a vfo?



  #3   Report Post  
Old May 12th 04, 03:35 AM
W3JDR
 
Posts: n/a
Default

I think the problem with these is going to be placing the bypass caps close
enough to the chip, and also getting good low-impedance RF ground paths.
For just a little more money, you can buy an entire DDS board with all parts
from NJQRP.

Let us know how you make out.

Joe
W3JDR


"Ken Scharf" wrote in message
...
For those trying to solder those TSSOP and TQFP AD
chips into a circuit I found this site on the net

http://aprilog.com/perl/main.pl

They sell adaptors to solder the chip onto to plug
into standard dip sockets.

There are other types of breadboard circuit boards
for these chips as well. Search on google for
"TSSOP breadboard" or "TQFP breadboard".

Now that I see it might be possible I'm going to try
and make use of those 9954 and 9851 chips I got as
samples. The 9932 looks interresting too, with it's
low power. I also want to get a sample of the 9834,
now THAT's a low power chip, perfect for QRP.

Anybody have any 'war stories' about using these DDS
chips in a rig as a vfo?



  #4   Report Post  
Old May 12th 04, 05:50 AM
John Miles
 
Posts: n/a
Default

In article ,
says...
For those trying to solder those TSSOP and TQFP AD
chips into a circuit I found this site on the net

http://aprilog.com/perl/main.pl

They sell adaptors to solder the chip onto to plug
into standard dip sockets.

There are other types of breadboard circuit boards
for these chips as well. Search on google for
"TSSOP breadboard" or "TQFP breadboard".

Now that I see it might be possible I'm going to try
and make use of those 9954 and 9851 chips I got as
samples. The 9932 looks interresting too, with it's
low power. I also want to get a sample of the 9834,
now THAT's a low power chip, perfect for QRP.

Anybody have any 'war stories' about using these DDS
chips in a rig as a vfo?


The Aprilog adaptors do work. I've used them on both AD9852/AD9854
chips and ATmega128 chips. Drawbacks a 1) they aren't exactly free;
and 2) Aprilog can be a little quirky to deal with at times, although
they've always come through for me in the end. (I think it's a one- or
two-man shop that sometimes gets overwhelmed with business.) They will
sometimes cut you a good deal on slightly-nonstandard stock.

They are certainly preferable to hand-soldering. I'd say give 'em a try
with the 9900-series DDS parts and report back to let us know your
results.

-- jm

------------------------------------------------------
http://www.qsl.net/ke5fx
Note: My E-mail address has been altered to avoid spam
------------------------------------------------------
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Old May 12th 04, 05:50 AM
John Miles
 
Posts: n/a
Default

In article ,
says...
For those trying to solder those TSSOP and TQFP AD
chips into a circuit I found this site on the net

http://aprilog.com/perl/main.pl

They sell adaptors to solder the chip onto to plug
into standard dip sockets.

There are other types of breadboard circuit boards
for these chips as well. Search on google for
"TSSOP breadboard" or "TQFP breadboard".

Now that I see it might be possible I'm going to try
and make use of those 9954 and 9851 chips I got as
samples. The 9932 looks interresting too, with it's
low power. I also want to get a sample of the 9834,
now THAT's a low power chip, perfect for QRP.

Anybody have any 'war stories' about using these DDS
chips in a rig as a vfo?


The Aprilog adaptors do work. I've used them on both AD9852/AD9854
chips and ATmega128 chips. Drawbacks a 1) they aren't exactly free;
and 2) Aprilog can be a little quirky to deal with at times, although
they've always come through for me in the end. (I think it's a one- or
two-man shop that sometimes gets overwhelmed with business.) They will
sometimes cut you a good deal on slightly-nonstandard stock.

They are certainly preferable to hand-soldering. I'd say give 'em a try
with the 9900-series DDS parts and report back to let us know your
results.

-- jm

------------------------------------------------------
http://www.qsl.net/ke5fx
Note: My E-mail address has been altered to avoid spam
------------------------------------------------------


  #6   Report Post  
Old May 12th 04, 02:02 PM
xpyttl
 
Posts: n/a
Default

"Ken Scharf" wrote in message
...

Now that I see it might be possible I'm going to try
and make use of those 9954 and 9851 chips I got as
samples. The 9932 looks interresting too, with it's
low power. I also want to get a sample of the 9834,
now THAT's a low power chip, perfect for QRP.


Well, don't be too excited just yet. Even though the chips themselves might
be on a diet, they need a high frequency oscillator to get a decent waveform
out. Those little oscillator cans start to draw amazing amounts of current
when the frequency creeps up. Heck, the ocsillator on my 9850 DDS draws
more current by itself than an entire K1.

FAR circuits has a DDS board that is a little more complete than the NJQRP
dauhtercard, if that's what you are looking for, but the quality of that
board has been pretty bad. I know they are trying to improve it, but I
can't say I've been impressed with the results. On the other hand, they do
have prototyping boards that are quite nice. I picked up a few at a hamfest
this past fall that are pretty decent for the TSSOP DDS parts. And they are
a LOT cheaper than the individual adapters. However, their online catalog
doesn't have the selection they had at the hamfest, so maybe a call to them
would be in order.

The NJQRP daughtercard really does reduce the pain of all this, but both the
daughtercard and the FAR circuits DDS card are for the 9850, which is
getting a little stale. Sounds like you want to play with some newer stuff.

Also take a peek at some of the TI stuff. They have synthesizers and
"transmitter" chips that are very reasonably priced. Although they are
intended for very high frequencies, Steve Weber has made them work down into
more reasonable frequencies, and prescalers are only a couple of bucks.

...


  #7   Report Post  
Old May 12th 04, 02:02 PM
xpyttl
 
Posts: n/a
Default

"Ken Scharf" wrote in message
...

Now that I see it might be possible I'm going to try
and make use of those 9954 and 9851 chips I got as
samples. The 9932 looks interresting too, with it's
low power. I also want to get a sample of the 9834,
now THAT's a low power chip, perfect for QRP.


Well, don't be too excited just yet. Even though the chips themselves might
be on a diet, they need a high frequency oscillator to get a decent waveform
out. Those little oscillator cans start to draw amazing amounts of current
when the frequency creeps up. Heck, the ocsillator on my 9850 DDS draws
more current by itself than an entire K1.

FAR circuits has a DDS board that is a little more complete than the NJQRP
dauhtercard, if that's what you are looking for, but the quality of that
board has been pretty bad. I know they are trying to improve it, but I
can't say I've been impressed with the results. On the other hand, they do
have prototyping boards that are quite nice. I picked up a few at a hamfest
this past fall that are pretty decent for the TSSOP DDS parts. And they are
a LOT cheaper than the individual adapters. However, their online catalog
doesn't have the selection they had at the hamfest, so maybe a call to them
would be in order.

The NJQRP daughtercard really does reduce the pain of all this, but both the
daughtercard and the FAR circuits DDS card are for the 9850, which is
getting a little stale. Sounds like you want to play with some newer stuff.

Also take a peek at some of the TI stuff. They have synthesizers and
"transmitter" chips that are very reasonably priced. Although they are
intended for very high frequencies, Steve Weber has made them work down into
more reasonable frequencies, and prescalers are only a couple of bucks.

...


  #8   Report Post  
Old May 12th 04, 03:30 PM
PaoloC
 
Posts: n/a
Default

xpyttl wrote:

Hi

Also take a peek at some of the TI stuff. They have synthesizers and
"transmitter" chips that are very reasonably priced. Although they are
intended for very high frequencies, Steve Weber has made them work down into
more reasonable frequencies, and prescalers are only a couple of bucks.


Do you have any reference to Weber's project? I would love to have a
look at that circuit!

BTW, do you mean SteveN Weber, KD1JV?

Thanks,
Paolo IK1ZYW
  #9   Report Post  
Old May 12th 04, 03:30 PM
PaoloC
 
Posts: n/a
Default

xpyttl wrote:

Hi

Also take a peek at some of the TI stuff. They have synthesizers and
"transmitter" chips that are very reasonably priced. Although they are
intended for very high frequencies, Steve Weber has made them work down into
more reasonable frequencies, and prescalers are only a couple of bucks.


Do you have any reference to Weber's project? I would love to have a
look at that circuit!

BTW, do you mean SteveN Weber, KD1JV?

Thanks,
Paolo IK1ZYW
  #10   Report Post  
Old May 13th 04, 01:30 AM
Ken Scharf
 
Posts: n/a
Default

xpyttl wrote:
"Ken Scharf" wrote in message
...


Now that I see it might be possible I'm going to try
and make use of those 9954 and 9851 chips I got as
samples. The 9932 looks interresting too, with it's
low power. I also want to get a sample of the 9834,
now THAT's a low power chip, perfect for QRP.



Well, don't be too excited just yet. Even though the chips themselves might
be on a diet, they need a high frequency oscillator to get a decent waveform
out. Those little oscillator cans start to draw amazing amounts of current
when the frequency creeps up. Heck, the ocsillator on my 9850 DDS draws
more current by itself than an entire K1.

FAR circuits has a DDS board that is a little more complete than the NJQRP
dauhtercard, if that's what you are looking for, but the quality of that
board has been pretty bad. I know they are trying to improve it, but I
can't say I've been impressed with the results. On the other hand, they do
have prototyping boards that are quite nice. I picked up a few at a hamfest
this past fall that are pretty decent for the TSSOP DDS parts. And they are
a LOT cheaper than the individual adapters. However, their online catalog
doesn't have the selection they had at the hamfest, so maybe a call to them
would be in order.

The NJQRP daughtercard really does reduce the pain of all this, but both the
daughtercard and the FAR circuits DDS card are for the 9850, which is
getting a little stale. Sounds like you want to play with some newer stuff.

Also take a peek at some of the TI stuff. They have synthesizers and
"transmitter" chips that are very reasonably priced. Although they are
intended for very high frequencies, Steve Weber has made them work down into
more reasonable frequencies, and prescalers are only a couple of bucks.

I haven't found a link where you can buy the NJQRP daughtercard, he
seems to have the artwork for downloading but that won't do me much
good. The 9851 seems to be pin compatible with the 9850 and will go
higher in frequency using a lower frequency (lower powered) oscillator.
The 9954 family is much smaller in size than the 9850 family (closer
pin spacing) so dead bug on these would be about impossible, the
circuit board is a must. I found some other bread board adaptors but
the problem is that there can't be any traces UNDER the 9954 because
there is a ground pad there. I can carefully cut away the unused
portions of one of these (http://www.devrs.com/store/) which is a
universal breadboard, drill a hole through the middle and solder
a wire to the ground pad. BTW I thought I'd have a problem interfacing
to the 9954 because it runs on 1.8v (how to hook it to a 5v 8051?), but
the io part of the chip is powered by it's own pin that can run at 3.3v
and then it will tolerate 5.5v max on the digital inputs. Problem
solved!

BTW many here seem to like PICs, but I'm just more familiar with the
8051 series. IF you don't need external ram or io on the 8031 and
and use an external EPROM you still have 16 io lines available, it's
then a three chip solution (8031, 74x573, 27x512). There are simulators
C compilers and assemblers for the 8051 that run on Linux (don't know
about the pics). I DO wish that people that post articles using these
micros on the web or in qst would make the SOURCE CODE available!!!
Not doing so is like NOT making the SCHEMATIC available for a homebrew
article!!!
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