Driving Video
Typical Application Circuits
The SGM806x can be used in video applications like in Figure 5.
Differential Amplifier
The circuit shown in Figure 3 performs the difference function.
If the resistors ratios are equal ( R4 / R3 = R2 / R1 ), then
VIN
75Ω
V
OUT = ( Vp – Vn ) × R2 / R1 + Vref.
SGM8061
75Ω
CABLE
R2
RF
VOUT
R1
Vn
RG
75Ω
VOUT
SGM8061
Vp
R3
G = 1 + RF / RG
R4
Figure 5. Typical Video Driving
Vref
Figure 3. Differential Amplifier
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 1/2πR2C. 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.
C
R2
R1
VIN
VOUT
SGM8061
R3 = R1 // R2
Figure 4. Low Pass Active Filter
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SGM8061/2/3