EEVblog #587 - Tektronix MDO3000 Mixed Domain Oscilloscope Teardown

[EEVblog]

What's inside Tektronix's new MDO3000 Mixed Domain Oscilloscope?
Does does a teardown and looks at the circuitry and how they can get such a cheap 3GHz RF spectrum analyser to work.
Datasheets:
HMC624 Digital RF Attenuator: https://www.hittite.com/content/documents/data_sheet/hmc624alp4.pdf
HMC311 InGaP HBT GAIN BLOCK https://www.hittite.com/content/documents/data_sheet/hmc311lp3.pdf
HMC429 VCO: https://www.hittite.com/content/documents/data_sheet/hmc429lp4.pdf
Lattice LFE3 FPGA: http://www.mouser.com/ds/2/225/Lattice%20-%20ECP3-270819.pdf
77725 LDO: http://www.ti.com/lit/ds/symlink/tps77725.pdf
i.MX6 ARM Applications Processor: http://cache.freescale.com/files/32bit/doc/fact_sheet/IMX6SRSFS.pdf
PECL Buffer: http://www.micrel.com/_PDF/HBW/sy10-100ep11u.pdf
ADF4360 VCO: http://www.analog.com/static/imported-files/data_sheets/ADF4360-7.pdf
1Gb DDR2 SDRAM: https://www.micron.com/parts/dram/ddr2-sdram/mt47h64m16hr-25e
Secrets Behind the MDO Spectrum Analyser: http://www.tek.com/dl/48W-28882-2%20%20%20MDO%20Performance%20WP_.pdf

[bronson]

Great review Dave.  Drool.

Pretty sure your 8-pin "360" package is actually an "09E".  Pulsar QE-09-E maybe?

http://www.pulsarmicrowave.com/spec_sheets/QE-09-E.pdf?140108

The pinout might agree: pin 2 wyes out into pins 5 and 8, then it's mirrored back together on the other side.

I'm horrible at RF though so I could be completely wrong.  Would love to hear a little more detail on how this little strip works.

EDIT: good shots just before and after the 48:00 minute mark.

[mikeselectricstuff]

The "Must cover/May cover" is for conformal coating to reduce leakage of the battery supply - you can see the coating on the PCB in the vid
 

[bronson]

Gotta say, I'm not a fan of that airflow...  Those narrow heatsink fins will be clogged with gray gunk in two years.  Might be an issue since the video hints that the Tek is running near the edge of the heat envelope anyway.

The boards that the air flows across will get gunky too.  But, since they're all digital, that seems a minor aesthetic concern.

If it must blow in, would a filter have added so much to the cost...?

[mikeselectricstuff]

I reckon the central chip is the ADC, the other two doing data/memory management for the scope channels.
Presumably 10gsps, which is interleaved down for scope mode

[Psi]

Just a thought, those large blobs of solder on the RF connector maybe intentional to make the solder surface smooth and avoid sharp points for RF reasons.

[EEVblog]

The "Must cover/May cover" is for conformal coating to reduce leakage of the battery supply - you can see the coating on the PCB in the vid

Ah, so it is, didn't notice that in the light and on the screen.

[EEVblog]

I reckon the central chip is the ADC, the other two doing data/memory management for the scope channels.
Presumably 10gsps, which is interleaved down for scope mode

It could be a 4 channel ADC, that was one of my guesses.
From a wafer process point of view that might make sense, as it's a 5GHz input bandwidth ADC, high end stuff.
Although integrating a 2CH ADC with memory management might make sense from a throughput point of view.
The two outer chips at the very least do contain memory management, although I suspect they do more than that.

[orion242]

Nice teardown 

[mikeselectricstuff]

A 10gsps ADC is pretty near alien tech, probably with some wacky-arse exotic process - I doubt you'd put memory control type stuff on the same die, though I suppose it could be a multi-die package.

[EEVblog]

A 10gsps ADC is pretty near alien tech, probably with some wacky-arse exotic process - I doubt you'd put memory control type stuff on the same die, though I suppose it could be a multi-die package.

They are only 5Gsps each. Presumably the <500MHz models that are only 2.5Gsps each use the same 5Gsps capable chip. They would stagger them all to get the 10Gsps required for the RF sampling.

Perhaps Alan can find out for us...

[zapta]

How a complex PCB like the main one is typically designed? A single person does all the work? A team split the work and merges the sub designs?  It's look took complex for one person and I can't see how the design is split.

Edit: I am referring to the PCB layout, not the electronic design.

[nitro2k01]

I  noticed something relatively insignificant in the PSU. Notice how the TO-220 on the riser board has one leg bent forward. The only reason I can think of for doing that is mechanical support. They really, really don't want anything flapping in the breeze!

[bronson]

Ha, they didn't spare any conformal coating did they?  It just covers Must Cover.

Maybe the May Cover guy was was a serious pessimist.

Right around 43:00 for anyone else who wants to see what anti-leakage looks like.

[AlphZeta]

Just checked, the model Dave had (MDO3104) cost JUST $13,900.00

[darrell]

The 8 pin parts bypassing the amplifier in the RF section are almost certainly switches. Macom MASW-007107 is pin compatible. https://www.macomtech.com/datasheets/MASW-007107.pdf

The two white things on the output of the HMC429 are Mini-Circuits LFCN series low pass filters. The forked line just past those is a Wilkinson splitter. The extra length on one side is 180 degrees to create differential output. My guess is the the differential RF from the input as well as the VCO signal go down vias to a differential pair near the transformer.

[EEVblog]

How a complex PCB like the main one is typically designed? A single person does all the work? A team split the work and merges the sub designs?  It's look took complex for one person and I can't see how the design is split.
Edit: I am referring to the PCB layout, not the electronic design.

That PCB layout can easily be done by one person. In fact it is best done by one person. As former full time PCB designer myself, that complexity board is not an issue. Usually a several week job, or usually more. There is often lots of back-and-forth forth with the circuit designer, production and product design people.
The actual bulk layout itself is only several days work once you get everything in place ready to route.

[NiHaoMike]

I  noticed something relatively insignificant in the PSU. Notice how the TO-220 on the riser board has one leg bent forward. The only reason I can think of for doing that is mechanical support. They really, really don't want anything flapping in the breeze!

That looks more like it's for clearance.

[BravoV]

I  noticed something relatively insignificant in the PSU. Notice how the TO-220 on the riser board has one leg bent forward. The only reason I can think of for doing that is mechanical support. They really, really don't want anything flapping in the breeze!

Don't think the psu manufacturer bent it, its the standard staggered TO-220 pins that is originally formed that way from that chip manufacturer.

[robrenz]

Nice teardown Dave, I learned a lot 

[Smokey]

That looks more like it's for clearance.

Watch out with this.   No matter how you bend them, the leads are always the same distance apart when they enter the package.

[EEVblog]

Watch out with this.   No matter how you bend them, the leads are always the same distance apart when they enter the package.

Yes, but you have a datasheet to tell you what the max spec is. You're on your own when you mount it on a board.

[Zad]

Could the 'touch sensor' be for condensation detection?

[EEVblog]

Could the 'touch sensor' be for condensation detection?

With the solder mask on?

[hikariuk]

I love that they still use the same blue colour for the back that my ancient Tektronix 5115 oscilloscope sat behind me used.  Little things please me (I'm a simple person, really).