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choosing 2.048 voltage reference?

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Sajjadkhan

Sajjadkhan

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i have to connect a 2.048 voltage reference to an 12bit ADC MCP3204. i have come down to a result of 2 chips.
1. ADR380 $1.95
2. Ref191 (25PPM) $3.2
3. Ref191 (5PPM) $5.72

Here is the digikey filtered result:

https://www.digikey.com/scripts/dks...&ptm=0&fid=0&quantity=0&PV-5=23463&PV-5=21047

I have to use it in an environment of temperature like 10-45 degree C. and your circuit is as good as its reference, so please help me choose which one is best?
 

How do you define "best"? Lowest price? Tolerance?

If you don't need 5ppm, than why pay for it? The adr380 has an initial tolerance of 0.24%==>5mV, this is actually better than the REF191(10mv) with the same temp coefficient.
 

You don't say what accuracy you require but if cost is important, the LM4040 series tend to be reasonably priced.

Keith
 

I would define best if the performance fits a certain scenario with the lowest cost. lets say as an example that i am making an accurate current meter which measure down to 1mA and up to (4096-1) mA by using mcp3204 12 bit adc. so i have calculated that for 25ppm ADR380, if temperature changes from 25 degree C to 50 Degree C and current is 1.500 Amps@ 25 degree, then after a 25 degree change my current display will still be 1.5009 amps. so i guess ADR380 would be ok.
 

You need to look carefully at the curves rather than just using ppm values. Over such a limited temperature range you are working over what is usually the flattest part of the temperature curve. Also, I assume "initial accuracy" will be important to you.

Keith
 

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