Precise voltage reference VLSI

Thread Starter

mos_6502

Joined Dec 11, 2017
28
Hi to all,

Is there a way to generate a precise reference voltage starting from a stable external power supply (eg +3 / -3V from +2.5 / -2.5v)?

I should do this in an IC (I'm simulating with Tanner EDA and a 0.25um layout).

I heard about the "charge pumps", could I use one?But I do not know how they work and even what are the design criteria.

Can you help me?
 

danadak

Joined Mar 10, 2018
3,627
The most stable internal commercial Vref I am aware of on FPGA,
VLSI, is a just borderline reference on PSOC 5LP family of ARM
micros. Its +/- .1 %. I do not know if that is laser trimmed at production
or its intrinsic properties. Note thats a 25 C spec.

upload_2019-2-15_11-54-2.png

Regards, Dana.
 

dendad

Joined Feb 20, 2016
3,084
In a couple of our products, we used pretty good voltage reference ICs.
The first is one with a temperature controlled heater built in.
It is an LM3999H.
20190218_083813.jpg
The lower spec version uses a MAX6341.
20190218_083831.jpg
Both circuits have precision resistors, 15PPM, 0.1%.
20190218_083725.jpg
Better Vrefs and resisters can be used but these are quite adequate. Probably better Vrefs are available now too.
The ADC has a MUX on the inputs so the processor can read a terminated input for a zero reading, then a measured test voltage that is formed from the Vref and the precision resistor in a voltage divider, and then the unknown input signal voltage.

The test voltage is measured on setup with a lab quality meter and the value stored in EEPROM.
This way, the system can self calibrate for more accurate readings.

This setup has been in use now for quite a few years in precision water MagFlow meters.
 
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