- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄367561 > LM2457 PDF資料下載
參數(shù)資料
| 型號(hào)： | LM2457 |
| 文件頁數(shù)： | 9/14頁 |
| 文件大小： | 823K |
| 代理商： | LM2457 |
Application Hints
(Continued)
clock frequencies up to 95MHz. A sample of this design
along with all necessary support hardware and materials can
be obtained from your local sales office.
PC Board Layout Considerations
For optimum performance, an adequate ground plane, iso-
lation between channels, good supply bypassing and mini-
mizing unwanted feedback are necessary.Also, the length of
the signal traces from the preamplifier to the LM2457 and
from the LM2457 to the CRT cathode should be as short as
possible.
Due to the high gain and bandwidth of the LM2457, the part
may oscillate in a monitor if feedback occurs around the
video channel through the chassis wiring. To prevent this,
leads to the video amplifier input circuit should be shielded,
and input circuit wiring should be spaced as far as possible
from output circuit wiring.
IMPORTANT LAYOUT CONSIDERATIONS
The NSC reference design can be used directly or it can be
used as a guide for future layouts. Note the location of the
following components:
C48—V
CC
bypass capacitor, located very close to pin 7
and the device ground.
C8—V
BB
bypass capacitor, located close to pin 8 and
ground.
C34,C35, C46—V
bypass capacitors, near LM2457
V
CC
clamp diodes. Very important for arc protection. Note
the direct path from the capacitor ground to the LM2457
ground.
C25-27—clamp output bypass caps. Very important for a
stable DC clamp voltage and for protecting the clamp
outputs from damage due to a CRT arc.
The routing of the LM2457 video outputs to the CRT is very
critical to achieving optimum performance. Figure 20 shows
the routing and component placement from pin 1 of the
LM2457 to the blue cathode. Note that the components are
placed so that they almost line up from the output pin of the
LM2457 to the blue cathode pin of the CRT connector. This
is done to minimize the length of the video path between
these two components. Note also that D16, D17, R17 and
D7 are placed to minimize the size of the video nodes that
they are attached to. This minimizes parasitic capacitance in
the video path and also enhances the effectiveness of the
protection diodes. The anode of protection diode D17 is
connected directly to a section of the ground plane that has
a short and direct path to the LM2457 ground pins. The
cathode of D16 is connected to V
very close to decoupling
capacitor C34, which is connected to the same section of the
ground plane as D17. The diode placement and routing is
very important for minimizing the voltage stress on the
LM2457 video outputs during an arc over event. Lastly,
notice that S1 is placed very close to the blue cathode and is
tied directly to the ground under the CRT connector.
L
www.national.com
9
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LM2465TA | Analog IC |
| LM246D | PROGRAMMABLE QUAD BIPOLAR OPERATIONAL AMPLIFIERS |
| LM246N | PROGRAMMABLE QUAD BIPOLAR OPERATIONAL AMPLIFIERS |
| LM246DT | OP-AMP|QUAD|BIPOLAR|SOP|16PIN|PLASTIC |
| LM246J | Voltage-Feedback Operational Amplifier |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LM2459 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Monolithic Single Channel 15 MHz DTV CRT Driver |
| LM2459C WAF | 制造商:Texas Instruments 功能描述: |
| LM2459TE | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Monolithic Single Channel 15 MHz DTV CRT Driver |
| LM246 | 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:PROGRAMMABLE QUAD BIPOLAR OPERATIONAL AMPLIFIERS |
| LM2460 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Monolithic Triple Channel High Swing CRT Driver |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。