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
V
OUT
= ( Vp – Vn ) × R
2
/ R
1
+ Vref.
Driving Video
The SGM805x can be used in video applications like in Figure 5
.
V
IN
SGM8051
75Ω
R2
Vn
Vp
R3
R4
Vref
Figure 3. Differential Amplifier
75Ω
CABLE
R1
SGM8051
R
G
V
OUT
R
F
75Ω
V
OUT
G = 1 + R
F
/ R
G
Figure 5. Typical Video Driving
Low Pass Active Filter
The low pass filter shown in Figure 4 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.
C
R2
R1
V
IN
SGM8051
V
OUT
R3=R1//R2
Figure 4. Low Pass Active Filter
１０
SGM8051/2/3/4/5
SGMICRO [ Shengbang Microelectronics Co, Ltd ]
