Yet Another Voltage Reference Post

The founder of this company had started tinkering with voltage reference ever since he started messing around electronics design with printed circuit board, reflowing soldering. 

The scène of the voltage reference has changed over the past decade slightly. When he started there were only three known metrology grade options, LTZ1000, LTFLU, and  SZA263. Maybe LM199/LM399 also made the cut. Now we have quite a few more contenders, ADR1399, ADR1000, ADR1001 and REF80. 

There are also options that capable of operating at low voltage, less than the 7V-ish minimum voltage required for Buried Zener. The first one introduced is LTC6655 and later TI's competing part, REF70 series. These two the best designed band-gap voltage references. They are very good if we have a design constraint when only 3.3V presents on the board. This is actually a quite common application case in mixed-domain data acquisition system. Most high-speed data-acquisition system don't go beyond 5V output, and for sure the ADC and DAC don't take 10V or even 5V reference input. The latest high-speed low-noise semiconductor processes just simply don't like 15V. 

There is also a odd candidate that worth mentioning, 2DW232 and its siblings from 上海无线电十七厂 , which gives extremely low noise (better than LTZ1000), but fall short in terms of temperature coefficient and long term stability. 

Here are something the may interests people. 

1. bootstrap the drive voltage of ADR1399 LM399

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2. ADR1399 thermal control

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3. Temperature controlled 2DW232

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