Motore di ricerca datesheet componenti elettronici
  Italian  ▼
ALLDATASHEETIT.COM

X  

LM2403 Scheda tecnica(PDF) 5 Page - National Semiconductor (TI)

[Old version datasheet] Texas Instruments acquired National semiconductor.
Il numero della parte LM2403
Spiegazioni elettronici  Monolithic Triple 4.5 nS CRT Driver
Download  11 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Produttore elettronici  NSC [National Semiconductor (TI)]
Homepage  http://www.national.com
Logo NSC - National Semiconductor (TI)

LM2403 Scheda tecnica(HTML) 5 Page - National Semiconductor (TI)

  LM2403 Datasheet HTML 1Page - National Semiconductor (TI) LM2403 Datasheet HTML 2Page - National Semiconductor (TI) LM2403 Datasheet HTML 3Page - National Semiconductor (TI) LM2403 Datasheet HTML 4Page - National Semiconductor (TI) LM2403 Datasheet HTML 5Page - National Semiconductor (TI) LM2403 Datasheet HTML 6Page - National Semiconductor (TI) LM2403 Datasheet HTML 7Page - National Semiconductor (TI) LM2403 Datasheet HTML 8Page - National Semiconductor (TI) LM2403 Datasheet HTML 9Page - National Semiconductor (TI) Next Button
Zoom Inzoom in Zoom Outzoom out
 5 / 11 page
background image
Application Hints (Continued)
will also help optimize rise and fall times as well as minimize
EMI. For proper arc protection, it is important to not omit any
of the arc protection components shown in
Figure 10.
OPTIMIZING TRANSIENT RESPONSE
Referring to
Figure 10, there are three components (R1, R2
and L1) that can be adjusted to optimize the transient re-
sponse of the application circuit. Increasing the values of R1
and R2 will slow the circuit down while decreasing over-
shoot. Increasing the value of L1 will speed up the circuit as
well as increase overshoot. It is very important to use induc-
tors with very high self-resonant frequencies, preferably
above 300 MHz. Ferrite core inductors from J.W. Miller Mag-
netics (part # 78FR12M) were used for optimizing the perfor-
mance of the device in the NSC application board. The val-
ues shown in
Figure 10 can be used as a good starting point
for the evaluation of the LM2403. The NSC demo board also
has a position open to add a resistor in parallel with L1. This
resistor can be used to help control overshoot. Using vari-
able resistors for R1 and the parallel resistor is a great way
to help dial in the values needed for optimum performance in
a given application.
Pull-up Resistors
Optimizing the performance of the LM2403 does require the
use of pull-up resistors at the outputs of the CRT driver.
These resistors are shown as R100, R101, and R102 in the
schematic. If you have a demo board form National please
note that these resistors have been added on the back of the
board since there is no PCB location for the pull-up resistors.
Because of the improved performance with these resistors,
all demo boards have been shipped with the added pull-up
resistors. The LM2403 does have some crossover distortion,
normal for any AB amplifier such as the LM2403. Adding the
pull-up resistors does add more bias to Q3 (
Figure 1) thus
minimizing the crossover distortion. The LM2403 is normally
used in high end monitors, so it is highly recommended that
the 12k pull-up resistors be used in any design using the
LM2403. Selecting a 12k resistor provides the needed
pull-up current and limits the worst case power dissipation to
1/4W (white level at 25V).
In some applications pull-down resistors may be preferred.
Using 12k resistors gives acceptable performance, but this
will require the use of 1/2W resistors. Normally the power
save mode establishes whether pull-up or pull-down resis-
tors are preferred. If the setup of the power save mode in the
monitor gives a low output at the LM2403, then the pull-down
resistors would be preferred, if the 80V supply is still turned
on.
Effect of Load Capacitance
The output rise and fall times as well as overshoot will vary
as the load capacitance varies. The values of the output cir-
cuit (R1, R2 and L1 in
Figure 10) should be chosen based on
the nominal load capacitance. Once this is done the perfor-
mance of the design can be checked by varying the load
based on what the expected variation will be.
For example, suppose you needed to drive a 10 pF (±20%)
load with a 40V
p-p waveform. First, you would pick the values
of R1, R2 and L1 that give the desired response with a 10 pF
load. Then you would test the design when driving an 8 pF
load and a 12 pF load. The table below summarizes the re-
sults from doing this exercise in a test board in the NSC lab.
The output signal swing was 40V
p-p from 65V to 25V.
Parameter
8 pF
10 pF
12 pF
Rise Time
4.1
4.2
4.3
Overshoot
1%
5%
10%
Fall Time
4.4
4.6
4.7
Overshoot
1%
2%
5%
The example above clearly demonstrates the importance of
having a good estimate of the range of the load capacitance.
Effect of Offset
Figure 7 shows the variation in rise and fall times when the
output offset of the device is varied from 30 V
DC to 50 VDC.
The rise time shows about twice as much variation as the fall
time, however the maximum variation relative to the center
data point (40 V
DC) is less than 10%.
Operation with V
CC = 70V
The closed loop topography of the LM2403 allows operation
down to 10V above ground. If the user can limit the white
level between 10V and 20V, then operation with V
CC = 70V
is possible. Operating the LM2403 with V
CC = 70V will re-
quire the same current even though the supply voltage has
dropped by 12.5%. This results in a power savings of 12.5%
(as high a 1.5W), allowing a reduction in the size of the heat-
sink.
Figure 8 shows the output waveform of the LM2403 op-
erating at a white level of 15V, and a peak-to-peak output
swing of 40V. Below is a summary of the LM2403 rise and
fall times with various output offset levels with V
CC = 70V.
DS100082-10
FIGURE 10. One Channel of the LM2403 with the Recommended Arc Protection Circuit
www.national.com
5


Codice articolo simile - LM2403

Produttore elettroniciIl numero della parteScheda tecnicaSpiegazioni elettronici
logo
Texas Instruments
LM2403 TI1-LM2403 Datasheet
2Mb / 15P
[Old version datasheet]   Monolithic Triple 4.5 nS CRT Driver
More results

Descrizione simile - LM2403

Produttore elettroniciIl numero della parteScheda tecnicaSpiegazioni elettronici
logo
National Semiconductor ...
LM2408 NSC-LM2408 Datasheet
154Kb / 8P
   Monolithic Triple 4.5 ns CRT Driver
logo
Texas Instruments
LM2403 TI1-LM2403 Datasheet
2Mb / 15P
[Old version datasheet]   Monolithic Triple 4.5 nS CRT Driver
logo
National Semiconductor ...
LM2470 NSC-LM2470 Datasheet
841Kb / 14P
   Monolithic Triple 7.0 ns CRT Driver
LM2405 NSC-LM2405 Datasheet
191Kb / 7P
   Monolithic Triple 7 ns CRT Driver
LM2415 NSC-LM2415 Datasheet
459Kb / 10P
   Monolithic Triple 5.5 ns CRT Driver
LM2439 NSC-LM2439 Datasheet
527Kb / 9P
   Monolithic Triple 9.5 ns CRT Driver
LM2402 NSC-LM2402 Datasheet
816Kb / 11P
   Monolithic Triple 3 ns CRT Driver
LM2412 NSC-LM2412 Datasheet
815Kb / 11P
   Monolithic Triple 2.8 ns CRT Driver
logo
Texas Instruments
LM2445 TI1-LM2445 Datasheet
1Mb / 15P
[Old version datasheet]   Monolithic Triple 7.5 ns CRT Driver
logo
National Semiconductor ...
LM2412A NSC-LM2412A Datasheet
818Kb / 11P
   Monolithic Triple 2.8 ns CRT Driver
More results


Html Pages

1 2 3 4 5 6 7 8 9 10 11


Scheda tecnica Scarica

Go To PDF Page


Link URL




Privacy Policy
ALLDATASHEETIT.COM
Lei ha avuto il aiuto da alldatasheet?  [ DONATE ] 

Di alldatasheet   |   Richest di pubblicita   |   contatti   |   Privacy Policy   |   scambio Link   |   Ricerca produttore
All Rights Reserved©Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp
Russian : Alldatasheetru.com  |   Korean : Alldatasheet.co.kr  |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com
Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl  |   Vietnamese : Alldatasheet.vn
Indian : Alldatasheet.in  |   Mexican : Alldatasheet.com.mx  |   British : Alldatasheet.co.uk  |   New Zealand : Alldatasheet.co.nz
Family Site : ic2ic.com  |   icmetro.com