SGM8541_17 Datasheet, PDF (9/18 Pages) SG Micro Corp – CMOS Operational Amplifiers

SGM8541/2/4
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 V_OUT = (V_p - V_n) × R₂/R₁ + V_REF.
R₂
R₁
V_n
V_p
R₃
SGM8541
V_OUT
R₄
V_REF
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.
SGM8541
V_n
V_p
SGM8541
R₂
R₁
SGM8541
R₃
R₄
V_OUT
V_REF
Figure 5. Instrumentation Amplifier
1.1MHz, 46μA, Rail-to-Rail I/O
CMOS Operational Amplifiers
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 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
SGM8541
V_OUT
R₃ = R₁ // R₂
Figure 6. Low-Pass Active Filter
SG Micro Corp
www.sg-micro.com
MARCH 2017
9