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參數(shù)資料
| 型號(hào)： | LM1253 |
| 廠商： | National Semiconductor Corporation |
| 英文描述： | Monolithic Triple 180 MHz I2C CRT Pre-amp With Integrated Analog On Screen Display (OSD) Generator |
| 中文描述： | 單片三180兆赫的I2C顯像管預(yù)先集成在屏幕顯示（OSD）發(fā)生器模擬放大器 |
| 文件頁數(shù)： | 16/57頁 |
| 文件大小： | 1621K |
| 代理商： | LM1253 |
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National VideoPlex Video System
(Continued)
ESD and Arc-Over Protection
The LM1253A incorporates full ESD protection with special
consideration given to maximizing arc-over robustness. The
monitor designer must still use good circuit design and PCB
layout techniques. The human body model ESD susceptibil-
ity of the LM1253A is 2 kV, however many monitor manufac-
turers are now testing their monitors to the level 4 of the IEC
801-2 specification which requires the monitor to survive an
8 kV discharge. External ESD protection is needed to sur-
vive this level of ESD. The LM1253A provides excellent pro-
tection against both ESD and arc-over, but this is not a sub-
stitute for good PCB layout.
Figure 26 show the recommended input protection for the
LM1253A. This provides the best protection against ESD.
When this protection is combined with good PCB layout the
LM1253A will easily survive the IEC 801-2 level 4 testing
(8 kV ESD). It is strongly recommended that the protection
diodes be added as shown in Figure 26 The 1N4148 diode
has a maximum capacitance of 4 pF which will have little ef-
fect on the response of the video system due to the low im-
pedance of the input video.
The ESD cells of the LM1253A also provide good protection
against arc-over, however good PCB layout is necessary.
The LM1253A should not be exposed directly to the voltages
that may occur during arc-over. The main vulnerability of the
LM1253A to arc-over is though the ground traces on the
PCB. For proper protection all ground connections associ-
ated with the LM1253A, including the grounds to the bypass
capacitors, must have short returns to the ground pins.Asig-
nificant ground plane should be used to connect all the
LM1253A grounds. Figure 31 which shows the demo board
layout, is an excellent example of an effective ground plane.
The list below should be followed to ensure a PCB with good
grounding:
All grounds associated with the LM1253A should be con-
nected together through a large ground plane.
CRT driver ground is connected to the video pre-amp
ground at one point.
CRT and arc protection grounds are connected directly to
the chassis or main ground. There is no arc-over current
flow from these grounds through the LM1253A grounds.
Input signal traces for SDA, SCL, H Flyback, V Flyback,
Clamp should be kept away from the LM2453 and all
traces that an arc can travel on.
Output signal traces of the LM1253A (video, V
,
V
) should be kept away from traces that carry the out-
put signals of the LM2453.
If any one of the above suggestions is not followed the
LM1253A may become more vulnerable to arc-over. Im-
proper grounding is by far the most common cause of a
video pre-amp failure during arc-over.
DS101265-27
FIGURE 24. DC I/O Transfer Characteristics for the LM2453 CRT Driver
(Test Conditions: V
REF
= 1.65V, V
CC1
= 80V, V
BB
= 8V)
DS101265-28
FIGURE 25. LM2453 Input and Output Waveforms
L
www.national.com
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PDF描述 |
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| LM1253AN | Monolithic Triple 180 MHz I2C CRT Pre-amp With Integrated Analog On Screen Display (OSD) Generator |
| LM1253A | Monolithic Triple 180 MHz I2C CRT Pre-amp With Integrated Analog On Screen Display (OSD) Generator |
| LM1262 | 200 MHz I2C Compatible RGB Video Amplifier System with OSD and DACs |
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LM1253A | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Monolithic Triple 180 MHz I2C CRT Pre-amp With Integrated Analog On Screen Display (OSD) Generator |
| LM1253AN | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Monolithic Triple 180 MHz I2C CRT Pre-amp With Integrated Analog On Screen Display (OSD) Generator |
| LM-1256 | 制造商:ROHM 制造商全稱:Rohm 功能描述:16 x 16 matrix displays |
| LM-1256_1 | 制造商:ROHM 制造商全稱:Rohm 功能描述:16】16 matrix displays |
| LM-1256LB1 | 制造商:ROHM 制造商全稱:Rohm 功能描述:16】16 matrix displays |
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