col_implant
New Member
Hi,
I'm hoping to use the PIC18F Comparator Voltage Reference CVref output to RA2 to provide the reference voltage for an op-amp level shifter, inverting with a variable gain.
According to the data sheet a buffer is advised on the output of CVref to deliver any signifiant current, obviously the current drawn by the amp V+ i/p will be tiny. Still this buffer requirement makes me nervous
My question is: Is there an output voltage buffer that will isolate the resistor string inside the PIC from my op-amp circuit?
My worry is that if there is no such buffer then the gain in the V- loop will have an effect on the reference voltage (ie difference amplifier type operation) as if a resistor divider was connected to the V+. MAybe I'm being over paranoid but better to be safe than sorry i guess
I'm hoping to use the PIC18F Comparator Voltage Reference CVref output to RA2 to provide the reference voltage for an op-amp level shifter, inverting with a variable gain.
According to the data sheet a buffer is advised on the output of CVref to deliver any signifiant current, obviously the current drawn by the amp V+ i/p will be tiny. Still this buffer requirement makes me nervous
My question is: Is there an output voltage buffer that will isolate the resistor string inside the PIC from my op-amp circuit?
My worry is that if there is no such buffer then the gain in the V- loop will have an effect on the reference voltage (ie difference amplifier type operation) as if a resistor divider was connected to the V+. MAybe I'm being over paranoid but better to be safe than sorry i guess
