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shunt voltage references can sink or source just fine right?

i need a 5V reference that can sink or source current for a DAC. a
simple shunt reference like the LM4040 can do both just fine right? my
thinking:

1- when the DAC is SINKING current, that means that current is flowing
through the shunt resistor and into the DAC reference input. as long
as the current into the DAC does not drop the voltage across the shunt
resistor below the voltage at which enough current will pass through
the shunt to maintain its accuracy, im fine, right?

2- and when the DAC is SOURCING current, all that source current flows
direcly through the shunt, and as long as it doesnt exceed the shunts
maximum current, the reference voltage is accurate.

thought #2 seems the easiest to analyze and Im pretty sure im 100%
right.

thought #1 im not so sure about...am I completely right or just close?
i feel like im close to the right concept but i dont know what the
exact numbers are.

Asa
 
T

Tony

Jan 1, 1970
0
i need a 5V reference that can sink or source current for a DAC. a
simple shunt reference like the LM4040 can do both just fine right? my
thinking:

1- when the DAC is SINKING current, that means that current is flowing
through the shunt resistor and into the DAC reference input. as long
as the current into the DAC does not drop the voltage across the shunt
resistor below the voltage at which enough current will pass through
the shunt to maintain its accuracy, im fine, right?

What you said was a bit mixed up. Current into the DAC doesn't drop the voltage across the
shunt resistor at all. It robs current from the shunt regulator, and when there's not
enough for regulation, the regulated voltage drops and the voltage across the shunt
resistor INCREASES.
 
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