lmp7718mmx National Semiconductor Corporation, lmp7718mmx Datasheet - Page 20

• Manufacturer Part Number: lmp7718mmx
• Description: 88 Mhz, Precision, Low Noise, 1.8v Cmos Input, Decompensated Operational Amplifier
• Manufacturer: National Semiconductor Corporation

www.national.com
In Figure 18 the ringing and the hump during the on time is
from the laser. The higher drive levels for the laser gave ring-
ing in the light source as well as light changing from the
thermal characteristics. The hump is due to the thermal char-
acteristics.
Solving for C
lated value is 0.54 pF. One of the problems with more gain is
the very small value for C
measured value being 0.64 pF. For the 0.64 pF location the
F
using a 100 kΩ feedback resistor, the calcu-
FIGURE 19. Rise Time
F
. A 0.5 pF capacitor was used, its
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20
pole is at 2.5 MHz. Figure 20 shows the response for a 1V
output.
A transimpedance amplifier is an excellent application for the
LMP7717. Even with the high gain using a 100 kΩ feedback
resistor, the bandwidth is still well over 1 MHz. Other than a
little over compensation for the 10 kΩ feedback resistor con-
figuration using the LMP7717 was quite easy. Of course a
very good board layout was also used for this test.
FIGURE 20. High Gain Response
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