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 ) × R
2
/ R
1
+ Vref.
C
R2
R1
V
IN
SGM8541
R2
Vn
Vp
R3
R4
Vref
Figure 4. Differential Amplifier
V
OUT
R1
SGM8541
V
OUT
R3 = R1 // R2
Figure 6. Low Pass Active Filter
Instrumentation Amplifier
The circuit in Figure 5 performs the same function as that in Figure 4
but with the high input impedance.
R2
R1
SGM8541
Vn
SGM8541
V
OUT
Vp
SGM8541
R3
R4
Vref
Figure 5. Instrumentation Amplifier
Low Pass Active Filter
The low pass filter shown in Figure 6 has a DC gain of ( - R
2
/ R
1
)
and the –3dB corner frequency is 1/2πR
2
C. 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.
８
SGM8541/8542/8544
SGMICRO [ Shengbang Microelectronics Co, Ltd ]
