SGM8531 Datasheet, PDF (8/16 Pages) SG Micro Corp – 500KHz,18μA, Rail-to-Rail I/O CMOS Operational Amplifier

Typical Application Circuits
Differential Amplifier
The circuit shown in Figure 4 performs the difference function.
If the resistors ratios are equal ( R4 / R3 = R2 / R1 ), then
V_OUT = ( Vp – Vn ) × R₂ / R₁ + Vref.
R2
R1
Vn
Vp
R3
SGM8531
R4
Vref
V_OUT
Figure 4. Differential Amplifier
Instrumentation Amplifier
The circuit in Figure 5 performs the same function as that in Figure
4 but with the high input impedance.
SGM8531
Vn
Vp
SGM8531
R2
R1
SGM8531
R3
R4
V_OUT
Vref
Figure 5. Instrumentation Amplifier
Low Pass Active Filter
The low pass filter shown in Figure 6 has a DC gain of ( - R₂ / R₁ )
and the –3dB corner frequency is 1/2πR₂C. Make sure the filter is
within the bandwidth of the amplifier. The Large values of feedback
resistors can couple with parasitic capacitance and cause
undesired effects such as ringing or oscillation in high-speed
amplifiers. Keep resistors value as low as possible and consistent
with output loading consideration.
R1
V_IN
C
R2
SGM8531
V_OUT
R3 = R1 // R2
Figure 6. Low Pass Active Filter
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SGM8531/8532/8534