BU7265G_1012 Datasheet, PDF (23/29 Pages) Rohm – Ultra Low Power CMOS Operational Amplifiers

BU7265G,BU7265SG,BU7205HFV,BU7205SHFV,BU7271G,BU7271SG,BU7245HFV,BU7245SHFV,
BU7411G,BU7411SG,BU7421G,BU7421SG,BU7475HFV,BU7475SHFV
●Examples of circuit
○Voltage follower
Technical Note
VDD
Voltage gain is 0 [dB].
This circuit controls output voltage (Vout) equal input
voltage (Vin), and keeps Vout with stable because of
high input impedance and low output impedance.
Vout is shown next formula.
Vout
Vout=Vin
Vin
VSS
Fig.167 voltage follower circuit
○Inverting amplifier
R1
Vin
R2
VDD
R1//R2
VSS
Vout
For inverting amplifier, Vin is amplified by voltage gain
decided R1 and R2, and phase reversed voltage is
outputed. Vout is shown next formula.
Vout=-(R2/R1)・Vin
Input impedance is R1.
Fig.168 Inverting amplifier circuit
○Non-inverting amplifier
R1
R2
VDD
Vin
Vout
For non-inverting amplifier, Vin is amplified by voltage
gain decided R1 and R2, and phase is same with Vin.
Vout is shown next formula.
Vout=(1+R2/R1)・Vin
This circuit realizes high input impedance because
Input impedance is operational amplifier’s input
Impedance.
VSS
Fig.169 Non-inverting amplifier circuit
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23/28
2010.12 - Rev.A