- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄385476 > LM2427 (National Semiconductor Corporation) Triple 80 MHz CRT Driver PDF資料下載
參數(shù)資料
| 型號(hào)： | LM2427 |
| 廠商： | National Semiconductor Corporation |
| 英文描述： | Triple 80 MHz CRT Driver |
| 中文描述： | 三80兆赫CRT顯示器驅(qū)動(dòng) |
| 文件頁數(shù)： | 4/6頁 |
| 文件大?。?/td> | 117K |
| 代理商： | LM2427 |
Application Hints
(Continued)
TILT AND OVERSHOOT COMPENSATlON
When a low frequency square is displayed on a monitor
screen, some tilt may appear on the video signal due to the
large power and thermal dissipation changes in the input
transistors. This problem is illustrated in Figure 3.
TL/H/11967–7
FIGURE 3. Tilt on a Low Frequency
Signal and Its Effects
The tilt can be compensated by adding an external RC feed-
back network as shown inFigure 4. The RC feedback helps
by reducing the gain of the amplifier during the edge tran-
sition for a duration corresponding to
u
. The values of R and
C should be selected so that the gain is reduced (
D
V
e
0)
for the duration of the tilt (
u
).
TL/H/11967–8
FIGURE 4. RC Feedback Network for Tilt Compensation
To find the value of resistor R, the following formula can be
used:
R
e
(100
b
x%)
x%
R
F
where x% is the percentage value of
D
V to the peak-to-
peak output swing (V
PP
). R
F
is internally fixed to 5700
X
.
The value of capacitor C is determined by:
C
e
u
/R
where
u
is the duration of the tilt.
For optimum results in a specific application, the values for
R and C may need to be tested and adjusted in the given
application board.
PROTECTlNG AMPLIFIER OUTPUT
FROM TUBE ARCING
During normal CRT operation, internal arcing may occasion-
ally occur. Spark gap protectors will limit the maximum volt-
age, but to a value that is much higher than allowable on the
LM2427. This fast, high voltage, high energy pulse can dam-
age the LM2427 output stage. The addition of two current
limiting resistors of 50
X
to 100
X
total, and clamping diodes
D1 and D2, will provide protection but will slow down the
response. The diodes should have a fast transient re-
sponse, high peak current rating, low series impedance and
low shunt capacitance. FDH400 or equivalent diodes are
recommended. Adding a series peaking inductor of 100 nH
to 150 nH will restore the bandwidth and provide additional
protection. (See Figure 5)
The value of the inductor can be calculated from:
Lp
e
(R
O
a
R
1
a
R
2
)
2
2.4
C
L
where C
L
is the total load and R
O
is the intrinsic high fre-
quency output resistance of the amplifier, generally 160
X
.
TL/H/11967–9
FIGURE 5. One Section of the LM2427
with Tilt Compensation, Arc Protection
and Peaking Inductance L
P
in the Output
SHORT CIRCUIT PROTECTION
WARNING!
To provide maximum output speed, the LM2427 does not
have short circuit protection. Shorting the output can de-
stroy the device.
SUPPLY BYPASSlNG
Although the LM2427 has internal supply bypassing, some
values of supply line inductance can cause ringing in the
supply lines. If this occurs, an additional bypass capacitor or
a low-pass filter should be placed as close as possible to
the supply (V
a
) pins of the LM2427.
CAPACITlVE LOADS
The LM2427 is designed to drive capacitive loads, however,
the very high output slew rate of about 13,700 V/
m
s can
result in charging currents of over 200 mA into a 20 pF load.
These very high currents can damage the output transistors.
HEAT SlNKlNG
Power consumption by the LM2427 will depend on the sup-
ply voltage used, the output loading, the peak-to-peak out-
put swing and the operating frequency. Since the LM2427
will dissipate up to 14W, an external heatsink is always re-
quired. The maximum allowed case temperature is 90
§
C. To
calculate maximum heatsink thermal resistance, use the fol-
lowing formula:
R
th
e
(90
§
C
b
Max Ambient)
14
.
4
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LM2427T | Triple 80 MHz CRT Driver |
| LM2433 | 220V Monolithic Single Channel 16 MHz EDTV CRT Driver |
| LM2435 | Monolithic Triple 5.5 ns CRT Driver |
| LM2435T | Monolithic Triple 5.5 ns CRT Driver |
| LM2437 | Monolithic Triple 7.5 ns CRT Driver |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LM2427T | 制造商:Panasonic Industrial Company 功能描述:IC |
| LM2429 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Monolithic Triple Channel 15 MHz DTV Driver |
| LM2429TE/NOPB | 制造商:Texas Instruments 功能描述:CRT DRVR 180V 11-Pin(11+Tab) TO-220 |
| LM243-155.52M | 制造商:CONNOR-WINFIELD 制造商全稱:Connor-Winfield Corporation 功能描述:5.0x7.0mm Surface Mount LVDS Clock Oscillator Series |
| LM2432 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:220V Monolithic Single Channel 37 MHz HDTV CRT Driver |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。