LM1207N National Semiconductor, LM1207N Datasheet - Page 20

• Manufacturer Part Number: LM1207N
• Manufacturer: National Semiconductor

Specifications of LM1207N

• Lead Free Status / RoHS Status: Not Compliant

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17d In these photographs the LM1205 rise time was 2 25
Applications of the LM1205 LM1207
and Clamp Gate inputs These two resistors also limit the
current during a voltage surge A larger resistor is required
because these inputs are DC coupled allowing the current
to continuously flow into these inputs before the monitor is
turned on 100
eo inputs because this resistance value will start to roll off
the frequency response of the LM1205 LM1207
Note that the layout shown in Figure 16 does have a very
extensive ground plane One must remember that the
LM1205 LM1207 is a 130 MHz 85 MHz part and a single
sided board is difficult to successfully design A ground
plane similar to the layout shown in Figure 16 must be pro-
vided for good performance of the LM1205 LM1207 when
using either a single sided or double sided board The layout
of this board demonstrates the importance of grounding
The results of this layout are shown in Figures 17a through
ns and its fall time was 3 00 ns For the LM1207 the rise
time was 4 10 ns and the fall time 3 85 ns The output was a
4 V
www national com
PP
signal and the cutoff voltage was set to 2V The
resistors are not recommended at the vid-
FIGURE 15 Demonstration Board Schematic
(Continued)
20
Systems John Wiley
overshoot will subsequently be filtered out by the loading
effects of the CRT driver stage and the CRT itself When the
LM1205 LM1207 is designed into a video board one must
keep the ground to the CRT driver stage separate from the
ground of the LM1205 LM1207
grounds together only at one point National Semiconductor
also manufactures a line of CRT drivers Please contact Na-
tional for additional information These drivers greatly simpli-
fy the driver design allowing for shorter design cycles Of
course the LM1205 LM1207 can also be designed with a
discrete driver stage Figure 18 shows a design using a sim-
ple cascode CRT driver The LM1205 LM1207 block would
be the same schematic as shown in Figure 15
REFERENCES
Zahid Rahim ‘‘Guide to CRT Video Design ’’ Application
Note 861 National Semiconductor Corp Jan 1993
Ott Henry W Noise Reduction Techniques in Electronic
Sons New York 1976
connecting the two
TL H 11881 – 23