Hello everybody
In an ADC, how Vref, input voltage range and voltage supply are related together ?
In an ADC, how Vref, input voltage range and voltage supply are related together ?
The question I'm less clear on is what the maximum safe input voltage is (in terms of damaging components, not in terms of getting accurate, meaningful readings.) I've seen devices which were safe up to their supply voltage, while others say they can be damaged by any input higher than Vref.The Vref is the limit of the a/d converter, so if you have a 10bit a/d with 1.024Vref, then each bit is worth 1mV , so if Vref is now 5V each bit is worth 4.88mV.
The modern pic micros now have an in built Vref from 1.024 to 4.096V.
You can't input a Voltage higher than the Vref, even if the chip has an External Vref pin, no point in setting a Vref of 10V when using a 5V supply it will damage the chip.The question I'm less clear on is what the maximum safe input voltage is (in terms of damaging components, not in terms of getting accurate, meaningful readings.) I've seen devices which were safe up to their supply voltage, while others say they can be damaged by any input higher than Vref.
Perhaps I've misread or misunderstood specs. Either way, it's a frustrating and confusing gray area for me.
I was thinking of the other way, not Vref higher than supply, but Vref lower than supply.You can't input a Voltage higher than the Vref, even if the chip has an External Vref pin, no point in setting a Vref of 10V when using a 5V supply it will damage the chip.
It all depends on the ADC in question and how it's configured...regardless of what anybody else has said.Hello everybody
In an ADC, how Vref, input voltage range and voltage supply are related together ?
Indeed!The datasheet is your friend.