LMH6601MG/NOPB National Semiconductor, LMH6601MG/NOPB Datasheet - Page 19

• Manufacturer Part Number: LMH6601MG/NOPB
• Description: IC AMP VFA 2.4V SHUTDOWN SC70-6
• Manufacturer: National Semiconductor

Specifications of LMH6601MG/NOPB

• Amplifier Type: Voltage Feedback
• Number Of Circuits: 1
• Output Type: Rail-to-Rail
• Slew Rate: 275 V/µs
• Gain Bandwidth Product: 155MHz
• -3db Bandwidth: 250MHz
• Current - Input Bias: 5pA
• Voltage - Input Offset: 1000µV
• Current - Supply: 9.6mA
• Current - Output / Channel: 180mA
• Voltage - Supply, Single/dual (±): 2.4 V ~ 5.5 V, ±1.2 V ~ 2.75 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: SC-70-6, SC-88, SOT-363
• Number Of Channels: 1
• Voltage Gain Db: 66 dB
• Common Mode Rejection Ratio (min): 56 dB
• Input Offset Voltage: 2.4 mV at 5 V
• Operating Supply Voltage: 3 V, 5 V
• Supply Current: 11.5 mA at 5 V
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• For Use With: LMH730227 - BOARD EVALUATION FOR SOIC PKGLMH730165 - BOARD EVALUATIONLMH730216 - BOARD EVAL HS MONO AMP SOT23
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: LMH6601MG; LMH6601MGTR

With the LMH6601 input common mode range including the
V
shifting and the input can directly drive the non-inverting input
which has the additional advantage of high amplifier input
impedance. With LMH6601’s wide rail-to-rail output swing, as
stated earlier, the video black level of 0V is maintained at the
load with minimal circuit complexity and using no AC coupling
capacitors. Without true rail-to-rail output swing of the
LMH6601, and more importantly without the LMH6601’s abil-
ity of exceedingly close swing to V
operate properly as shown at the expense of more complex-
ity. This circuit will also work for higher input voltages. The
only significant requirement is that there is at least 1.8V from
the maximum input voltage to the positive supply (V
The Composite Video Output of some low cost consumer
video equipment consists of a current source which develops
the video waveform across a load resistor (usually 75Ω), as
shown in
circuit configuration just described and shown in
be able to buffer and drive the Composite Video waveform
which includes sync and video combined. However, with this
arrangement, the LMH6601 supply voltage needs to be at
least 3.3V or higher in order to allow proper input common
mode voltage headroom because the input can be as high as
1V peak.
If the “Video In” signal is Composite Video with negative going
Sync tip, a variation of the previous configurations should be
used. This circuit produces a unipolar (above 0V) DC coupled
single supply video signal as shown in
−
FIGURE 6. Single Supply Composite Video Driver for
(ground) rail, there will be no need for AC coupling or level
Figure 6
Consumer Video Outputs
below. With these applications, the same
−
, the circuit would not
Figure
7.
Figure 6
+
).
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will
19
In the circuit of
of R
range. The signal will loose 20% of its amplitude in the pro-
cess. The closed loop gain of U1 will need to be set to make
up for this 20% loss in amplitude. This gives rise to the gain
expression shown below which is based on a getting a 2
V
R
in this case). R
tip (−0.3V at R
sponds to near 0V at the output.
Equation 1
to arrive at the values of R
From the datasheet, one can set R
recommended value for a gain of +2. It is easier to solve for
R
atively solving Equation and
Here is one possible iteration cycle for reference:
R
FIGURE 7. Single Supply DC Coupled Composite Video
PP
3
G
F
will produce a negative shift at the output due to V
= 620Ω
and R
1
output with a 0.8 V
, R
2
, and R
3
and
by starting with a good estimate for one and iter-
Driver for Negative Going Sync Tip
Figure
3
T
T
Equation 2
will need to be set so that the “Video In” sync
in order to satisfy U1’s Common Mode input
or 0.61V at U1 non-inverting input) corre-
7, the input is shifted positive by means
PP
3
input:
, R
need to be solved simultaneously
Equation 2
F
, and R
F
= 620Ω to be close to the
G
which will satisfy both.
to arrive at the results.
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S
(3.3V
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(1)
(2)