A quick update on the MDAC2 Analogue stage testing.
The MDAC2 is the first product that I've designed almost ground up with the aid of computer simulations.
Now that I have been able to re-establish my lab, I've had the chance to verify some of the more difficult to measure simulation results.
Working on the first version of the MDAC2 ClassA output stage had me worried for the past few days as the measured results and simulated results where very different. I had no way of knowing if it was a measurement or simulation error.
Dominik made the rather obvious suggestion to measure an off-the-shelf commercial Opamp and compare my measured results with the manufacturers Data sheet.
So I built a simple test circuit and was able to confirmed its a measurement system error - which I've now resolved.
Back to measuring the MDAC2 PCB and the results are now within the "correct ball park" the simulated results are still better, but I'm now able to optimise the component values on the PCB to achieve the design targets.
I'm chuffed that I can now "complete the circle" and confirm / tweak the "real hardware" so that I can close the gap with the simulated results.
The MDAC2 design is so complex that it can only be designed with the aid of the computer simulator so it was important that the real world and simulated result agreed with each other - otherwise I'd be in real trouble!
I hope that by the end of this month I'll have the most "feared" part of the analogue board tested and debugged.
I'm leaving confirmation of the clock performance for last as parts of the new test system are still in shipment - components of the system are so large and heavy that they are being shipped via Sea Cargo.
I'm not concerned about the clock performance at this stage, the design has been confirmed "Good" with the earlier Prototype PCB. Really the purpose of the new system is just to optimise the clock design - its "great" as it is, but I'd like to be sure its optimised to the very best performance the design allows. The clock performance is so fundamental to any DAC's performance that we want the very best - and to be able to provide the measured results to prove it!
Fingers crossed for the MDAC2 analogue stage!!! atleast I have access to the lab once again to confirm and debug if I encounter any difficulties and its reassuring to see that "So far" the simulated results are "workable", while not totally accurate they are still an important design tool.
The VFET amplifier circuit has also be designed and optimised via the use of the simulator, so again the results of the MDAC2 analogue board will help be critical to the "confidence" of the VFET design - pushing boundary requires support!
I'm very much pushing the boundary's of my design abilities with the MDAC2 / VFET amplifier circuits - so its really important that I can trust the simulation results.
Wow - after all of this work, they had better be stunning! I've been working for more then 3 years on the MDAC2 project, that's a far chunk of my working career.... Yes, I'm getting nervous as its all starting to come together finally!