NOTES ON OUTPUT VOLTAGE SETTINGS
R2
I2
VOUT
IIC
RIC
R3
I3
GND
2.0V
VOUT
Output setting voltage is determined using the following formulas :
I2=IIC+I3 ..........................................................................................(1)
I3=2.0/R3 ........................................................................................(2)
From (1) and (2) above,
I2=IIC+2.0/R3..................................................................................(3)
VOUT=2.0+R2 × I2............................................................................(4)
By substituting (3) into the above formula
VOUT=2.0+R2 × (IIC+2.0/R3)
=2.0 × (1+R2/R3)+R2 × IIC ....................................................(5)
The second term, R2 × IIC in the formula (5) above may cause a voltage setting error.
Here, consider the formula in terms of IIC,
IIC=2.0/RIC .....................................................................................(6)
then R2 × IIC that causes the error will be as shown below :
R2 × IIC=R2 × 2.0/RIC
=2.0 × R2/RIC......................................................................(7)
Thus, when R2<<RIC the error can be minimized.
RN5RY202
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