ADC converters in Siglent and Rigol oscilloscopes - Overheating and Cooling

[pascal_sweden]

Is there an overview and comparison available of the ADC converters in the different models and series of the Siglent and Rigol oscilloscopes?

Some Rigol oscilloscopes had overheating issues on the ADC converters due to improper heatsinks and/or cooling.

Are there similar overheating issues with Siglent oscilloscopes?

How does the new Rigol chipset perform in comparison with an off-the-shelf ADC converter?
Does it get very warm? Has somebody verified this with an IR camera?

Does Rigol apply proper heatsinks and/or cooling for their new chipset?

[Martin72]

Hi,

Example : Rigol MSO5000...

several temperatures measured

And in the first post of the thread it´s a vid-clip where at minute 22 Dave are scanning the board with a flir.

[TurboTom]

Apparently, at least with Rigol gear, heat sinking can vary widely. I was lucky with my MSO4000, manufactured early 2016, it has a substantial single-piece heat sink installed on the acquisition engine (covering four MXT2001 ADCs and four Virtex FPGAs). The fifth Virtex has an individual heat sink bonded on as well as the MSO piggyback FPGA (Spartan??):



Other owners of DS/MSO4000 series instruments reported several different cooling approaches on their instruments from almost non-existant to quite decent (individual heat sinks on all the FPGAs but not on the ADCs) Of course, if my unit, which AFAIK is the only reported one with the big, single heat sink, has installed proper thermal pads on all the semiconductors to transfer the heat, is still unknown. I didn't bother to rip the heat sink off...

Coherent with this is the cooling situation of my DS(MSO)2000A, individual heat sinks on all the FPGAs but not on the MXT2001 ADC. Considering that the ADC dissipates a maximum of 2W and is attached to the PCB with an additional thermal pad (25mm²), one may get along with this if an adequate PCB thermal design is applied, especially since this instrument has a single such ADC and and not three more fending in the neighbourhood (like the DS4000). Yet, the FPGA on the signal generator piggyback board is left without a heatsink. Maybe it's a small(er) unit that doesn't dissipate that much heat.



Unfortunately, I cannot report on Siglent or other, more recent scopes. But at least the Spartan 6 in the Siglent SSA3000X spectrum analyzer is running without additional heatsink. Presumably, the workload on the FPGA in this application is less than on the components of the acquisition engine of DSOs.

[pascal_sweden]

Is anybody aware of a commercial oscilloscope in which they use water cooling, or is this unexplored territory for oscilloscopes?

[Martin72]

Last, I think.
Or, maybe in the real big buddies from keysight and lecroy (wavemaster) - There´s enough space to place a watercooling system into it.
Of course, I saw this only from the personal computer sight, where the smallest watercooling thing could be to cool a gpu on a graphics card.

[jjoonathan]

The early Rigol DS4000 series didn't have a heat sink on the ADCs and just ran them hot. Naturally, they burned out early. Full story: https://goo.gl/photos/dxU3ChWUcvCMDW4N9



As a point of comparison, I can't help but include my Rohde & Schwarz RTO1024, which lies on the polar opposite end of the responsible thermal design spectrum. The ADCs have a large inlet fan to optimize flow/noise, a duct to channel the air where it is needed, and heat sinks sized to achieve uniform heat exchange despite their positions up/downstream from one another. Temperatures are monitored, fans are throttled accordingly, and if some goober gets a piece of paper stuck to the inlet it knows how to turn off the ADCs rather than let them fry. Also, it does a cute fan rev on startup.