SGM8091_15 Datasheet, PDF (10/18 Pages) SG Micro Corp – CMOS Operational Amplifiers

SGM8091/2/3/4
350MHz, Rail-to-Rail Output
CMOS Operational Amplifiers
TYPICAL APPLICATION CIRCUITS
Differential Amplifier
The circuit shown in Figure 3 performs the difference function.
If the resistors ratios are equal (R₄/R₃ = R₂/R₁), then
VOUT = (Vp - Vn) × R2/R1 + VREF.
R2
R1
Vn
SGM8091
VOUT
Vp
R3
Driving Video
The SGM8091/2/3/4 can be used in video applications like in
Figure 5.
VIN
SGM8091
RF
RG
75Ω
75Ω
CABLE
75Ω
VOUT
R4
VREF
Figure 3. Differential Amplifier
G = 1 + RF / RG
Figure 5. Typical Video Driving
Low Pass Active Filter
The low pass filter shown in Figure 4 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.
C
R2
R1
VIN
SGM8091
VOUT
R3 = R1 // R2
Figure 4. Low Pass Active Filter
SG Micro Corp
10
www.sg-micro.com