There are precision 1V voltage references like ADR510 which I don't have access to, though I do have LM385 1.2V, LM336Z5 5V and the famous TL431 at hand.

The easiest solution is to use a voltage divider:


simulate this circuit – Schematic created using CircuitLab

But using voltage dividers is not temperature coefficient, in page 6 of LM336 datasheet there's a schematic which claims:

If minimum temperature coefficient is desired, four diodes can be added in series with the adjustment potentiometer as shown in Figure 2. When the device is adjusted to 5.00V the temperature coefficient is minimized. Almost any silicon signal diode can be used for this purpose such as a 1N914,1N4148 or a 1N457.

  • How diodes makes above circuit temperature coefficient?
  • How do I achieve a temperature coefficient 1V voltage reference?
  • \$\begingroup\$ What is the required operating temperature range and stability? \$\endgroup\$ – Bruce Abbott Dec 25 '19 at 22:31
  • \$\begingroup\$ @BruceAbbott room temperature +~20 degree celsius. \$\endgroup\$ – ElectronSurf Dec 25 '19 at 22:39

There are two questions:

1) About diodes and temperature coefficient: the p-n junction in conduction state has voltage drop about 0.5V...0.8V, and - what is interesting, temperature coefficient of this drop is near constant and equal -2.2mV/K (without valuable dependency on current and voltage drop). This -2.2mV/K coefficient is the result of some physical properties of junctions based on silicon. So, this coefficient is very frequently used for compensation of temperature drift, because it is well defined.

2) About drift of 1V reference voltage: it depends on type of IC, used as reference: each IC type has own temperature coefficient - you can find this in reference data of this IC. For example, LM385 is very well compensated in temperatures about room temperature (25 Celsjus degrees), and - in typical applications - don't need additional compensation. If you need better compensation, there is no universal rule for all cases. You need always start with checking manufacturer's recomendations, very often placed in application notes. For example, TI in his datasheet shows precision 10V source built on LM385 (Fig. 17 in http://www.ti.com/lit/ds/symlink/lm285-adj.pdf).

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    \$\begingroup\$ Thanks, so the voltage divider solution is good enough to use? \$\endgroup\$ – ElectronSurf Dec 25 '19 at 23:22
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    \$\begingroup\$ Of course - resistors has very low temperature coefficient, additionaly in divider connection this coefficient is partially compensated, so you can safely assume, taht the dividing ratio is very stable in large range of temperature. \$\endgroup\$ – VillageTech Dec 25 '19 at 23:25
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    \$\begingroup\$ @VillageTech: Tip of the day: SE supports HTML entities including &Omega;, &deg;, &mu; &pm; and many more as well as <sub>...</sub> and <sup>...</sup>. So &deg;C for degrees celcius (which is lowercase when spelled out as per SI standard for units named after a person). These tricks don't work in the comments. \$\endgroup\$ – Transistor Dec 25 '19 at 23:30
  • \$\begingroup\$ Thx a lot, @Transistor ;) \$\endgroup\$ – VillageTech Dec 25 '19 at 23:36
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    \$\begingroup\$ @RussellMcMahon: I'm wrong! I've just checked: of all people, it's Celcius. "The names of all units start with a lower case letter except, of course, at the beginning of the sentence. There is one exception: in "degree Celsius" (symbol °C) the unit "degree" is lower case but the modifier "Celsius" is capitalized. Thus, body temperature is written as 37 degrees Celsius." NIST.gov. Thanks! \$\endgroup\$ – Transistor Dec 26 '19 at 0:11

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