SGM8532_15 Datasheet, PDF (8/15 Pages) SG Micro Corp – CMOS Operational Amplifiers

SGM8531/2/4
500kHz, 18μA, Rail-to-Rail I/O
CMOS Operational Amplifiers
TYPICAL APPLICATION CIRCUITS
Differential Amplifier
The circuit shown in Figure 4 performs the difference function. If
the resistor ratios are equal to (R₄ / R₃ = R₂ / R₁), then
VOUT = (Vp - Vn) × R2 / R1 + VREF.
R₂
R₁
Vn
Vp
R₃
SGM8531
R₄
V_REF
V_OUT
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 1/2R₂C. Make sure the filter
bandwidth 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 resistor values as low
as possible and consistent with output loading consideration.
R₁
V_IN
C
R₂
SGM8531
V_OUT
Figure 4. Differential Amplifier
Instrumentation Amplifier
The circuit in Figure 5 performs the same function as that in
Figure 4 but with a high input impedance.
R₂
R₁
SGM8531
Vn
SGM8531
V_OUT
R₃ = R₁ // R₂
Figure 6. Low Pass Active Filter
Vp
R₃
R₄
SGM8531
V_REF
Figure 5. Instrumentation Amplifier
SG Micro Corp
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