LMH6647MA National Semiconductor, LMH6647MA Datasheet - Page 16

• Manufacturer Part Number: LMH6647MA
• Description: AMP, 0.65MA 80MHZ, SOIC8, POWERWISE
• Manufacturer: National Semiconductor

Specifications of LMH6647MA

• Op Amp Type: Rail To Rail
• No. Of Amplifiers: 1
• Bandwidth: 55MHz
• Slew Rate: 22V/µs
• Supply Voltage Range: 2.5V To 12V
• Amplifier Case Style: SOIC
• No. Of Pins: 8
• Operating Temperature Range: -40°C To
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

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Application Notes
Figure 6 shows the MUX output when selecting between a
1MHz sine and a 250KHz triangular waveform.
As can be seen in Figure 6, the output is well behaved and
there are no spikes or glitches due to the switching. Switch-
ing times are approximately around 500ns based on the time
when the output is considered “valid”.
PRINTED CIRCUIT BOARD LAYOUT, COMPONENT
VALUES SELECTION, AND EVALUATION BOARDS
Generally, a good high-frequency layout will keep power
supply and ground traces away from the inverting input and
output pins. Parasitic capacitances on these nodes to
FIGURE 6. 2:1 MUX Output
(Continued)
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ground will cause frequency response peaking and possible
circuit oscillations (see Application Note OA-15 for more
information).
Another important parameter in working with high speed/
high performance amplifiers, is the component values selec-
tion. Choosing large valued external resistors, will effect the
closed loop behavior of the stage because of the interaction
of these resistors with parasitic capacitances. These capaci-
tors could be inherent to the device or a by-product of the
board layout and component placement. Either way, keeping
the resistor values lower, will diminish this interaction. On the
other hand, choosing very low value resistors could load
down nodes and will contribute to higher overall power dis-
sipation.
National Semiconductor suggests the following evaluation
boards as a guide for high frequency layout and as an aid in
device testing and characterization:
These free evaluation boards are shipped when a device
sample request is placed with National Semiconductor.
LMH6647 Evaluation
For normal operation, tie the SD pin to V
Device
LMH6645MF
LMH6645MA
LMH6646MA
LMH6646MM
LMH6647MA
LMH6647MF
Package
SOT23-5
8-Pin SOIC
8-Pin SOIC
8-Pin MSOP
8-Pin SOIC
SOT23-6
Evaluation
Board PN
CLC730068
CLC730027
CLC730036
CLC730123
CLC730027
CLC730116
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