BU7485G-TR Datasheet, PDF (28/43 Pages) Rohm – Ground Sense High Speed Low Voltage CMOS Operational Amplifiers

BU7485G BU7485SG BU7486xxx BU7486Sxxx BU7487xx BU7487Sxx ^Datasheet
Application example
○Voltage follower
VDD
Voltage gain is 0dB.
Using this circuit, the output voltage (OUT) is configured
OUT
to be equal to the input voltage (IN). This circuit also
IN
stabilizes the output voltage (OUT) due to high input
VSS
impedance and low output impedance. Computation for
output voltage (OUT) is shown below.
OUT=IN
Figure 75. Voltage follower
○Inverting amplifier
R1
IN
R2
VDD
OUT
For inverting amplifier, input voltage (IN) is amplified by
a voltage gain and depends on the ratio of R1 and R2.
The out-of-phase output voltage is shown in the next
expression
OUT=-(R2/R1)・IN
This circuit has input impedance equal to R1.
VSS
Figure 76. Inverting amplifier circuit
○Non-inverting amplifier
R1
R2
VDD
IN
VSS
OUT
For non-inverting amplifier, input voltage (IN) is
amplified by a voltage gain, which depends on the ratio
of R1 and R2. The output voltage (OUT) is in-phase
with the input voltage (IN) and is shown in the next
expression.
OUT=(1 + R2/R1)・IN
Effectively, this circuit has high input impedance since
its input side is the same as that of the operational
amplifier.
Figure 77. Non-inverting amplifier circuit
www.rohm.com
© 2013 ROHM Co., Ltd. All rights reserved.
TSZ22111ï½¥15ï½¥001
28/39
TSZ02201-0RAR1G200380-1-2
12.JUL.2013 Rev.001