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#1
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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
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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
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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? |
#5
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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
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"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
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"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
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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
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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
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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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