EEVblog 1431 - Keysight EDU33212A Function Generator Teardown

[EEVblog]

Teardown of the new Keysight  EDU33212A 20MHz Function Generator

Odysee exclusive: https://odysee.com/@eevblog:7/Photo-Spectrometer-Teardown:7

[Anthocyanina]

"FUNC_30M_V1.04"
Hmmm, that "30M" makes me wonder, are they thinking of releasing a 30Mhz software upgrade at some point?

[TheSteve]

Sure seems they had 30 MHz in mind doesn't it.

Maybe Dave can hack it.

[radioing]

Hi, to parallelize CFAs in arb. generators is well known technique for years. The reason is to distribute power dissipation over more chips and to decrease the output current per chip which makes better THD, especially at upper part of frequency band and high voltage amplitude. What surprises me is that only two CFAs are used per channel. I remember Agilent or R&S arb. gen. where the same four CFAs were used in parallel and even they were with heatsinks, the temperature @20 MHz/10Vpp/50ohms load was really high. Maybe, that's the reason the '30M' label downs to 20 MHz in reality (together with THD worsening at higher freqs).

[Boscoe]

Nice video, Dave. I've always loved the tear downs.

Dave, I wonder if you could do a video on length matching. It's something I don't really understand as a few mm difference in length would only offer a difference in time of femto seconds assuming 1/3rd the speed of light. Nothing to really worry about.

It's interesting they went with Cyclone 10 + STM32 on this design. I assume it's because they could source the Zynqs at the mo?

[thm_w]

Hi, to parallelize CFAs in arb. generators is well known technique for years. The reason is to distribute power dissipation over more chips and to decrease the output current per chip which makes better THD, especially at upper part of frequency band and high voltage amplitude. What surprises me is that only two CFAs are used per channel. I remember Agilent or R&S arb. gen. where the same four CFAs were used in parallel and even they were with heatsinks, the temperature @20 MHz/10Vpp/50ohms load was really high. Maybe, that's the reason the '30M' label downs to 20 MHz in reality (together with THD worsening at higher freqs).

Its a low cost EDU product, so I doubt they care much about high end specs.

- Output voltage spec is 10Vpp.
- THS3091 is rated 350mA.
- +/-15V rails thats a drop of 5V, at 100mA into 100R load. ~0.5W?

May or may not be a bit high depending on what part they used. Then you *know* the fact students will short the output, that would be 200mA, so 1W.
So it could be more of a matter of safe temperature of the IC, as you noticed.

[radioing]

May or may not be a bit high depending on what part they used. Then you *know* the fact students will short the output, that would be 200mA, so 1W.

And don't forget the dissipated power due to quiescent current attacking 10 mAmps -> 300 mW per IC.
But now I see the difference, they used package with PowerPAD which approx. doubles power rating.

[Anthocyanina]

seems like the "30M" marking really was about the frequency of the generator! found this today on the service guide! I wonder then why they released it as a 20MHz generator, hmmm.
https://www.keysight.com/zz/en/assets/9921-01385/service-manuals/EDU33210-Series-Trueform-Arbitrary-Waveform-Generator-Service-Guide.pdf