AD8091ARZ Analog Devices Inc, AD8091ARZ Datasheet - Page 14

• Manufacturer Part Number: AD8091ARZ
• Description: IC OPAMP VF R-R LDIST LP 8SOIC
• Manufacturer: Analog Devices Inc

Specifications of AD8091ARZ

• Slew Rate: 170 V/µs
• Amplifier Type: Voltage Feedback
• Number Of Circuits: 1
• Output Type: Rail-to-Rail
• -3db Bandwidth: 110MHz
• Current - Input Bias: 1.4µA
• Voltage - Input Offset: 1800µV
• Current - Supply: 4.8mA
• Current - Output / Channel: 45mA
• Voltage - Supply, Single/dual (±): 3 V ~ 12 V, ±1.5 V ~ 6 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Op Amp Type: Voltage Feedback
• No. Of Amplifiers: 1
• Bandwidth: 110MHz
• Supply Voltage Range: 3V To 12V
• Amplifier Case Style: SOIC
• No. Of Pins: 8
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Gain Bandwidth Product: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

AD8091/AD8092
The frequency response of the circuit is shown in Figure 34.
SYNC STRIPPER
Synchronizing pulses are sometimes carried on video signals so
as not to require a separate channel to carry the synchronizing
information. However, for some functions, such as A/D
conversion, it is not desirable to have the sync pulses on the
video signal. These pulses reduce the dynamic range of the
video signal and do not provide any useful information for such
a function.
A sync stripper removes the synchronizing pulses from a video
signal while passing all the useful video information. Figure 35
shows a practical single-supply circuit that uses only a single
AD8091. It is capable of directly driving a reverse terminated
video line.
The video signal plus sync is applied to the noninverting input
with the proper termination. The amplifier gain is set equal to 2
via the two 1 kΩ resistors in the feedback circuit. A bias voltage
must be applied to R1 for the input signal to have the sync
pulses stripped at the proper level.
The blanking level of the input video pulse is the desired place
to remove the sync information. The amplifier multiplies this
level by 2. This level must be at ground at the output in order
for the sync stripping action to take place. Because the gain of
the amplifier from the input of R1 to the output is −1, a voltage
equal to 2 × V
come out at ground.
V
IN
Figure 34. Frequency Response of 2 MHz Band-Pass Biquad Filter
3kΩ
–10
–20
–30
–40
R1
0
10k
2
3
BLANK
50pF
Figure 33. 2 MHz Biquad Band-Pass Filter
2kΩ
AD8092
C1
R2
must be applied to make the blanking level
1
100k
2kΩ
R3
FREQUENCY (Hz)
6
5
AD8092
2kΩ
1kΩ
R4
R6
1M
7
2kΩ
R5
2
3
10M
50pF
AD8091
C2
6
V
100M
OUT
Rev. C | Page 14 of 20
SINGLE-SUPPLY COMPOSITE VIDEO LINE DRIVER
Many composite video signals have their blanking level at
ground and have video information that is both positive and
negative. Such signals require dual-supply amplifiers to pass
them. However, by ac level-shifting, a single-supply amplifier
can be used to pass these signals. The following complications
may arise from such techniques.
Signals of bounded peak-to-peak amplitude that vary in duty
cycle require larger dynamic swing capacity than their
(bounded) peak-to-peak amplitude after they are ac-coupled.
As a worst case, the dynamic signal swing approaches twice the
peak-to-peak value. One of two conditions that define the
maximum dynamic swing requirements is a signal that is
mostly low but goes high with a duty cycle that is a small
fraction of a percent. The opposite condition defines the second
condition.
The worst case of composite video is not quite this demanding.
One bounding condition is a signal that is mostly black for an
entire frame but has a white (full amplitude) minimum width
spike at least once in a frame.
The other extreme is a full white video signal. The blanking
intervals and sync tips of such a signal have negative-going
excursions in compliance with the composite video
specifications. The combination of horizontal and vertical
blanking intervals limit such a signal to being at the highest
(white) level for a maximum of about 75% of the time.
As a result of the duty cycles between the two extremes, a 1 V
p-p composite video signal that is multiplied by a gain of 2
requires about 3.2 V p-p of dynamic voltage swing at the output
for an op amp to pass a composite video signal of arbitrary
varying duty cycle without distortion.
GROUND
V
BLANK
V
IN
VIDEO WITH SYNC
(OR 2 × V
+0.8V
Figure 35. Sync Stripper
R1
1kΩ
BLANK
3
2
+0.4V
AD8091
3V OR 5V
)
4
7
1kΩ
R2
6
0.1µF
VIDEO WITHOUT SYNC
+
10µF
100Ω
TO A/D
GROUND