Circuit Challenge 5
Consider the circuit shown below.
Core Circuitry for a Voltage Reference
Practitioners of the electronics arts (particularly those who design and use voltage references) will recognize the schematic as a basic building block for bandgap references. (Note: The circuit could have been inverted, thus permitting the use of PNPs.)
Assume VBE1=0.57V at the design center.
Assume IC1=IC2=100μA at the design center.
Assume VIN=1.25V at the design center.
Determine the approximate value of R1.
Determine the approximate value of R2.
Sketch the transfer characteristics of IC1 & IC2 versus VIN, for 0V < VIN < 1.5V.
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