EVAL-AD5791SDZ and LTZ1000 Voltage Reference / HP3458A



I am a so called 'volt-nut' and waste my time on ppm's instead of women, wine and song.


I have 2 questions to ADI:


1/ Why is the PCB space to the right almost totally undocumented? A little reverse engineering shows that the tracing fits (almost a copy of) a Linear Technology datasheet circuit for the LTZ1000.


2/ Why do you lock the step/ladder/ramp measurement to HP3458A? I understand you need a good instrument to verify a good ADC, but letting people use a 34401A or whatever will give the possibility to evaluate the voltmeter by using the DAC. Also, ADI uses some VISA/LabView stuff for the software. Imo very bad. Many people will not touch NI's LabView. As this demo board is a specialized product with a very small user base, why not just publish the code for the evaluation software (Microchip does this for their DataView software). In fact - any DVM with an external trig and RS232 can be used.


Also - in these modern times I would suggest/expect at least a skeleton of code in an application note describing use of the demo board (or the chip) with a microcontroller. You don't need more than an Arduino to go through the voltage output steps, send a trigger pulse to EXT TRIG and collect the data via RS232. We don't really need the ADI GUI code, but the DAC control loop and linearity check algorithm in C would be nice to have. After all - this setup is not some proprietary game - it is more like applied science and should imo be documented and be accessible as such.