OPA3682 Datasheet, PDF (14/19 Pages) Burr-Brown (TI) – Triple, Wideband, Fixed Gain BUFFER AMPLIFIER With Disable

This triple op amp could also be used to drive triple video
ADCs to digitize component video.
HIGH SPEED INSTRUMENTATION AMPLIFIER
Figure 3 shows an instrumentation amplifier based on the
OPA3682. The offset matching between inputs makes this an
attractive input stage for this application. The differential-to-
single-ended gain for this circuit is 2.0V/V. The inputs are
high impedance, with only 1pF to ground at each input. The
loads on the OPA3682 outputs are equal for the best harmonic
distortion possible.
MULTIPLEXED CONVERTER DRIVER
The converter driver in Figure 4 multiplexes among the
three input signals. The OPA3682s enable and disable times
support multiplexing among video signals. The “make-
before-break” disable characteristic of the OPA3682 ensures
that the output is always under control. To avoid large
switching glitches, switch during the sync or retrace por-
tions of the video signal—the two inputs should be almost
equal at these times. Because the output is always under
control, the switching glitches for two 0V inputs are
< 20mV. With standard video signals levels at the inputs, the
maximum differential voltage across the disabled inputs will
not exceed the ±1.2V maximum rating.
V₁
1/3
OPA3682
400Ω
400Ω
400Ω
400Ω
1/3
OPA3682
V₂
200Ω
200Ω
1/3
OPA3682
400Ω
400Ω
V_OUT
FIGURE 3. High-Speed Instrumentation Amplifier.
V₁
1/3
OPA3682
400Ω
400Ω
100Ω
4.99kΩ
0.1µF
4.99kΩ
0.1µF
V₂
1/3
OPA3682
400Ω
400Ω
V₃
1/3
OPA3682
100Ω
0.1µF
100pF
100Ω
0.1µF
REFT REFB
+3.5V +1.5V
+In
–In
CM
ADS823
10-Bit
60MSPS
400Ω
400Ω
Selection
Logic
FIGURE 4. Multiplexed Converter Driver.
®
OPA3682
14