Date   
Re: AD9850/51 module pc boards

William R Maxwell
 

Nicely done Terry. I'll certainly take a couple once you get to production.

Bill VK7MX

On 30/09/2018 1:34 PM, Terry VK5TM wrote:
Updated pics with the 3.3v reg underneath the Xtal osc.

I have moved some things around to shorten the length of tracks between IC output, transformer and pin at the edge of the pcb.

Will leave this alone for a day or two, firstly so any comments can be added/updated and secondly, I find getting away from a design sometimes suggests improvements that can be made or something shows that has been missed (like a power track missing in the first set of pics).

Re: AD9850/51 module pc boards

Terry VK5TM
 

Updated pics with the 3.3v reg underneath the Xtal osc.

I have moved some things around to shorten the length of tracks between IC output, transformer and pin at the edge of the pcb.

Will leave this alone for a day or two, firstly so any comments can be added/updated and secondly, I find getting away from a design sometimes suggests improvements that can be made or something shows that has been missed (like a power track missing in the first set of pics).

Re: AD9850/51 module pc boards

Terry VK5TM
 

I've seen at least three different options for using 3.3v oscillator modules on 5V boards, namely:

a couple of series diodes
a 47 ohm resistor
a proper 3.3v regulator.

The first two options work, but do have their own problems, so I will go with the third option of a 3.3v LDO reg.
I will use the LP2985 which is rated at 150mA so will cope with a TCXO and is readily available at Mouser.

And just in case anybody is wondering why not run the whole thing at 3.3v, the AD9850/51 is not specced to run at it's maximum possible osc speed at 3.3v.
While they do and are being run in that condition on the modules, current consumption and heat generation are increased markedly.

Re: AD9850/51 module pc boards

Tony Jaques
 

Hi all,
Three things: One is that if the distortion introduced by an AD8008 output stage can not be tolerated the perhaps the AD985x device is not a good enough starting point. (Search the files for "an investigation into output stages" - or something close to it.
The second is that modifying the module to give the oscillator a 3.3 volts supply. Again there is a message somewhere in which I show my solution to that. A search in messages might find it, but i no longer remember what the subject line was.
A third comment is that, if you have a 'scope, do make sure that you allow for Gary A Winblad's sweep modification later, even if you don't add it to start with.

I agree - very nicely done board layout Terry.

Tony Jaques (G3PTD)

Re: AD9850/51 module pc boards

Henning Weddig
 

Terry,

Your pcb looks awfully good! Especially that You have included an output transformer whcih is already suggested in an Analog Devices app note.

For the 125 Mhz osc: I think there is still some space left to include a 3V3 LDO for the xtal osc. To my knowledge most of the xtal oscs and especially the SMD types are for 3V3.

I am sure Your board will be a bestseller as the chinese units are getting up and up in price.

73

Henning Weddig

DK5LV

Am 29.09.2018 um 04:10 schrieb Terry VK5TM:

Here is a preliminary 3 pics of the pcb, combined top and bottom layers, top only and bottom only.
Nothing is set in concrete, so changes can be made. The other style module version could also be done.

Couple of points to note:
Obvious one is there is no on-board filter.
The output is through a 1:1 transformer (Coilcraft), this can be changed, but the transformer gives a better output signal both level wise and harmonic suppression wise.
There are some either/or components depending on whether the square wave output is required, these will be explained fully if this goes any further than just an idea.
Most smd components are 0805 sized rather than the smaller size on the current modules.

Re: AD9850/51 module pc boards

Steven Dick
 

I think you'll be hard pressed finding a TCXO that runs on 5V.
-Steve K1RF

-----Original Message-----
From: Terry VK5TM
Sent: Saturday, September 29, 2018 7:29 AM
To: PHSNA@groups.io
Subject: Re: [PHSNA] AD9850/51 module pc boards

I think if the oscillator module has to be replaced, it should be replaced with a TCXO.

It is surprising how much change in frequency there is with just a light draft across the oscillator, even just breathing on them can produce a shift of more than 100Hz.

Re: AD9850/51 module pc boards

Terry VK5TM
 

I think if the oscillator module has to be replaced, it should be replaced with a TCXO.

It is surprising how much change in frequency there is with just a light draft across the oscillator, even just breathing on them can produce a shift of more than 100Hz.

Re: AD9850/51 module pc boards

Steven Dick
 

Looks good. I like the coilcraft transformer on-board as I have used one myself (Coilcraft WB1-6TSLB)
and it allows good wideband performance and adequate output power for me with a lowpass filter and no output power amp which adds harmonics. Some of those amps are marginal, some can oscillate if the layout is not adequate. There is a problem with the xtal oscillator on EBAY AD9851 type II boards. For the ebay modules. the AD9851 was running off 5 volts but its crystal oscillator also ran on 5 volts but was only rated for 3.3v. Make sure the xtal oscillator is really compatible with 5V input voltage.

for AD9850, 125 MHz oscillator labelled MCO 1510A 125 MHz TQG-9h is a 5 volt oscillator made by Shenzhen Great Electronics. Data sheet:

http://www.szgreat.com/UploadFiles/2010322153029.pdf

For AD9851, 30 MHz oscillator Type II AD9851 boards are labelled CETDCJ 30 032. They are made by Taiten Electronics. It is a 3.3V oscillator, much to my dismay. One of them already failed. See part numbering guide:

http://www.taitien.com.tw/db/download/Model%20Numbering%20Guide_XO.pdf

I ordered a CTS CB3-3C-30M0000 which is rated for 5V. Mouser sells them: https://www.mouser.com/ProductDetail/CTS-Electronic-Components/CB3-3C-30M0000?qs=HL%252bYNjdyZ0s2KrBi4NmH2g%3D%3D

See file https://groups.io/g/PHSNA/files/K1RF/Bandpass%20Filter%20measurement%20anomalies%20R2.pdf discussing output amplifier
and file https://groups.io/g/PHSNA/files/K1RF/Expected%20power%20output%20from%20Type%20II%20PHSNA.pdf
-Steve K1RF

-----Original Message-----
From: Terry VK5TM
Sent: Friday, September 28, 2018 10:10 PM
To: PHSNA@groups.io
Subject: Re: [PHSNA] AD9850/51 module pc boards

Here is a preliminary 3 pics of the pcb, combined top and bottom layers, top only and bottom only.
Nothing is set in concrete, so changes can be made. The other style module version could also be done.

Couple of points to note:
Obvious one is there is no on-board filter.
The output is through a 1:1 transformer (Coilcraft), this can be changed, but the transformer gives a better output signal both level wise and harmonic suppression wise.
There are some either/or components depending on whether the square wave output is required, these will be explained fully if this goes any further than just an idea.
Most smd components are 0805 sized rather than the smaller size on the current modules.

Re: AD9850/51 module pc boards

Terry VK5TM
 

Here is a preliminary 3 pics of the pcb, combined top and bottom layers, top only and bottom only.
Nothing is set in concrete, so changes can be made. The other style module version could also be done.

Couple of points to note:
Obvious one is there is no on-board filter.
The output is through a 1:1 transformer (Coilcraft), this can be changed, but the transformer gives a better output signal both level wise and harmonic suppression wise.
There are some either/or components depending on whether the square wave output is required, these will be explained fully if this goes any further than just an idea.
Most smd components are 0805 sized rather than the smaller size on the current modules.

Re: AD9850/51 module pc boards

Terry VK5TM
 

Type 1 or 2?

I have one (single row of pins each side) without the filter components on board 3/4 done which I mentioned in an email to Jim a little while ago.

Give me a day or so and I will post it in the files section, but would appreciate someone just doing a double check to make sure here are no errors.

Re: AD9850/51 module pc boards

Jim Pruitt
 

The DDS60 is a totally different footprint than the AD9850 modules and will not work for my application.

Thank you.

Jim Pruitt
WA7DUY

On 9/28/2018 10:27 AM, Dave Hartman via Groups.Io wrote:
Maybe you can buy an unpopulated DDS-60 Daughtercard board from Midnight Design Solutions here:
https://midnightdesignsolutions.com/dds60/index.html
The DDS board is described here also:
http://cwtd.org/Jun4.html

Re: AD9850/51 module pc boards

EB4APL
 

There is a problem with this board, it is used in another version of the PHSNA (DDS-60 and Arduino Nano) so you will need the main board for it.

Regards,
Ignacio, EB4APL

El 28/09/2018 a las 19:27, Dave Hartman via Groups.Io escribió:
Maybe you can buy an unpopulated DDS-60 Daughtercard board from Midnight Design Solutions here:
https://midnightdesignsolutions.com/dds60/index.html
The DDS board is described here also:
http://cwtd.org/Jun4.html

Re: AD9850/51 module pc boards

DaveH52
 

Maybe you can buy an unpopulated DDS-60 Daughtercard board from Midnight Design Solutions here:
https://midnightdesignsolutions.com/dds60/index.html
The DDS board is described here also:
http://cwtd.org/Jun4.html
--

Dave - AC2GL
All typing errors are my own work and subject to copyright laws,
except errors by the spell checker which are open source.

AD9850/51 module pc boards

Jim Pruitt
 

I have several AD9850 samples.  I wonder if anyone knows where I can find the gerbers for the module pc boards themselves?  I would prefer to make my own and use my existing stash of chips rather than pay the high price they are going for these days.  So far I have not found that layout.  Someone on the QRP-Tech group said it might be open source since the Si5351 module layout is open source but I have no clue how to even search for that as Google has not been my friend on this so far!

Thank you.

Jim Pruitt
WA7DUY

Re: Very Late Start - Type 2

wb6ogd
 

Clifford,
Oh.! That looks like a good deal.
I still need a low phase noise LO for my
Picastar project.. humm.
73,
Gary
Wb6ogd

On Sep 26, 2018, at 4:55 PM, Clifford Heath <clifford.heath@...> wrote:

I bought this:

<https://www.aliexpress.com/item/Four-way-orthogonal-signal-generator-DDS-AD9959-core-board-200MHZ-AD9854/32713419146.html>,

but I recommend you spend $20 more and get one with transformers
or at least with video op-amps. The DACs in the AD9959 steer a
constant current through differential outputs, and it's important that
these outputs see the exact same load impedances to keep the
currents in balance. If not, the steered current fluctuates and that
makes the channels interfere with each other somewhat.

The bare chip is available (end of reel surplus) for ten bucks on
Aliexpress, if you can deal with the SMD.
<https://www.aliexpress.com/item/AD9959BCPZ-VFQFN-56-AD9959BCP/32787625498.html>

Second-hand gear is very expensive here in Australia. It's a small
enough market that it all gets bought by dealers who are prepared
to price it high and wait a long time.

Clifford Heath.

On 27 Sep 2018, at 8:46 am, wb6ogd <garywinblad@...> wrote:

Uh Clifford,
The eval board for AD9959 is $430 at Digikey.. Can you get those on ebay for cheap?

Si5351 board is about $7.

You might as well go buy a used HP or something, no?
I think I have about $25 in my PHSNA total out the door...

73,
Gary
WB6OGD


On 9/26/2018 3:32 PM, Clifford Heath wrote:
On 27 Sep 2018, at 12:09 am, wb6ogd <garywinblad@...> wrote:
True, the SI5351 is not best...
BUT, at higher freqs it's output becomes more sine wave. And at times, I thought I might want a higher freq
generator.
If you want higher frequencies, you should consider adapting PHSNA
to use the AD9959. You get four channels with a 500MHz core, so can
generate up to 200MHz sine waves. I've published driver code for it:
<https://github.com/cjheath/AD9959>

I'm using this in a new full multi-port VNA design which requires two
coherent channels (digitally phase locked, but sweeping on different
frequencies). I'll let you know how that progresses.

Clifford Heath.





Re: Very Late Start - Type 2

Curt
 

Thanks for aid and encouragement, from multiple continents. I got a handle on shopping now.

Great to discuss, learn or be reminded. Exciting third, fifth, etc harmonics not a good thing for filter measurement. I should have grasped that, but nice suggestion.

I am content to build with an ad9850 That is enough coverage for now. Brad's suggestion that jumpers aren't death to the product give some leeway. And I am reminded I can start assembly while awaiting the dds to arrive.

Very 73 Curt

Re: Very Late Start - Type 2

Clifford Heath
 

On 27 Sep 2018, at 10:04 am, K5ESS <k5ess.nothdurft@...> wrote:
Well as a matter of fact you can get them on ebay cheap(relatively). Item 183406561654. But you better hurry, there's only one left ;-)
That version is unbalanced, like the one I bought.

Clifford Heath.

Re: Very Late Start - Type 2

K5ESS
 

Well as a matter of fact you can get them on ebay cheap(relatively). Item 183406561654. But you better hurry, there's only one left ;-)
Mike
K5ESS

-----Original Message-----
From: PHSNA@groups.io [mailto:PHSNA@groups.io] On Behalf Of wb6ogd
Sent: Wednesday, September 26, 2018 5:47 PM
To: PHSNA@groups.io
Subject: Re: [PHSNA] Very Late Start - Type 2

Uh Clifford,
The eval board for AD9959 is $430 at Digikey.. Can you get those on
ebay for cheap?

Si5351 board is about $7.

You might as well go buy a used HP or something, no?
I think I have about $25 in my PHSNA total out the door...

73,
Gary
WB6OGD


On 9/26/2018 3:32 PM, Clifford Heath wrote:
On 27 Sep 2018, at 12:09 am, wb6ogd <garywinblad@...> wrote:
True, the SI5351 is not best...
BUT, at higher freqs it's output becomes more sine wave. And at times, I thought I might want a higher freq
generator.
If you want higher frequencies, you should consider adapting PHSNA
to use the AD9959. You get four channels with a 500MHz core, so can
generate up to 200MHz sine waves. I've published driver code for it:
<https://github.com/cjheath/AD9959>

I'm using this in a new full multi-port VNA design which requires two
coherent channels (digitally phase locked, but sweeping on different
frequencies). I'll let you know how that progresses.

Clifford Heath.


Re: Very Late Start - Type 2

Clifford Heath
 

I bought this:

<https://www.aliexpress.com/item/Four-way-orthogonal-signal-generator-DDS-AD9959-core-board-200MHZ-AD9854/32713419146.html>,

but I recommend you spend $20 more and get one with transformers
or at least with video op-amps. The DACs in the AD9959 steer a
constant current through differential outputs, and it's important that
these outputs see the exact same load impedances to keep the
currents in balance. If not, the steered current fluctuates and that
makes the channels interfere with each other somewhat.

The bare chip is available (end of reel surplus) for ten bucks on
Aliexpress, if you can deal with the SMD.
<https://www.aliexpress.com/item/AD9959BCPZ-VFQFN-56-AD9959BCP/32787625498.html>

Second-hand gear is very expensive here in Australia. It's a small
enough market that it all gets bought by dealers who are prepared
to price it high and wait a long time.

Clifford Heath.

On 27 Sep 2018, at 8:46 am, wb6ogd <garywinblad@...> wrote:

Uh Clifford,
The eval board for AD9959 is $430 at Digikey.. Can you get those on ebay for cheap?

Si5351 board is about $7.

You might as well go buy a used HP or something, no?
I think I have about $25 in my PHSNA total out the door...

73,
Gary
WB6OGD


On 9/26/2018 3:32 PM, Clifford Heath wrote:
On 27 Sep 2018, at 12:09 am, wb6ogd <garywinblad@...> wrote:
True, the SI5351 is not best...
BUT, at higher freqs it's output becomes more sine wave. And at times, I thought I might want a higher freq
generator.
If you want higher frequencies, you should consider adapting PHSNA
to use the AD9959. You get four channels with a 500MHz core, so can
generate up to 200MHz sine waves. I've published driver code for it:
<https://github.com/cjheath/AD9959>

I'm using this in a new full multi-port VNA design which requires two
coherent channels (digitally phase locked, but sweeping on different
frequencies). I'll let you know how that progresses.

Clifford Heath.



Re: Very Late Start - Type 2

wb6ogd
 

Uh Clifford,
The eval board for AD9959 is $430 at Digikey..  Can you get those on ebay  for cheap?

Si5351 board is about $7.

You might as well go buy a used HP or something, no?
I think I have about $25 in my PHSNA total out the door...

73,
Gary
WB6OGD

On 9/26/2018 3:32 PM, Clifford Heath wrote:
On 27 Sep 2018, at 12:09 am, wb6ogd <garywinblad@...> wrote:
True, the SI5351 is not best...
BUT, at higher freqs it's output becomes more sine wave. And at times, I thought I might want a higher freq
generator.
If you want higher frequencies, you should consider adapting PHSNA
to use the AD9959. You get four channels with a 500MHz core, so can
generate up to 200MHz sine waves. I've published driver code for it:
<https://github.com/cjheath/AD9959>

I'm using this in a new full multi-port VNA design which requires two
coherent channels (digitally phase locked, but sweeping on different
frequencies). I'll let you know how that progresses.

Clifford Heath.