lm2412a

Manufacturer Part Numberlm2412a
DescriptionMonolithic Triple 2.8 Ns Crt Driver
ManufacturerNational Semiconductor Corporation
lm2412a datasheet
 
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LM2412A
Monolithic Triple 2.8 ns CRT Driver
General Description
The LM2412A is an integrated high voltage CRT driver circuit
designed for use in high resolution color monitor applica-
tions. The IC contains three high input impedance, wide
band amplifiers which directly drive the RGB cathodes of a
CRT. Each channel has its gain internally set to −14 and can
drive CRT capacitive loads as well as resistive loads pre-
sented by other applications, limited only by the package’s
power dissipation.
The IC is packaged in an industry standard 11 lead TO-220
molded plastic power package. See thermal considerations
section for heat sinking requirements.
Features
n Rise/fall times typically 2.8 ns with 8 pF load at 40 V
Schematic and Connection Diagrams
FIGURE 1. Simplified Schematic Diagram
(One Channel)
© 2001 National Semiconductor Corporation
n Faster Maximum Rise/Fall time than LM2412, 3.2nsec
vs 3.5nsec.
n Well matched with LM2202 video preamps
n Output swing capability: 50 V
n 1V to 5V input range
n Stable with 0-20 pF capacitive loads and inductive
peaking networks
n Convenient TO-220 staggered lead package style
n Standard LM240X family pinout which is designed for
easy PCB layout
Applications
n CRT driver for color monitors with display resolutions up
to 1600 x 1200 with 85 Hz refresh rate
n Pixel clock frequency up to 200 MHz
PP
DS200124-1
DS200124
February 2001
for V
= 80V
PP
CC
DS200124-2
Top View
Order Number LM2412ATA
See NS package Number
www.national.com

lm2412a Summary of contents

  • Page 1

    ... LM2412A Monolithic Triple 2.8 ns CRT Driver General Description The LM2412A is an integrated high voltage CRT driver circuit designed for use in high resolution color monitor applica- tions. The IC contains three high input impedance, wide band amplifiers which directly drive the RGB cathodes of a CRT. Each channel has its gain internally set to −14 and can drive CRT capacitive loads as well as resistive loads pre- sented by other applications, limited only by the package’ ...

  • Page 2

    ... Note 7: 100% tested in production. These limits are not used to calculate outgoing quality levels. AC Test Circuit Figure 2 shows a typical test circuit for evaluation of the LM2412A. This circuit is designed to allow testing of the LM2412A environment without the use of an ex- pensive FET probe. The combined resitors of 4950 ...

  • Page 3

    Typical Performance Characteristics FIGURE OUT FIGURE 4. Speed vs Temp. FIGURE 5. Rise/Fall Time DS200124-4 FIGURE 6. Power Dissipation vs Frequency DS200124-6 DS200124-8 3 DS200124-5 DS200124-7 FIGURE 7. Speed vs Offset DS200124-9 FIGURE 8. Bandwidth ...

  • Page 4

    ... pull-up resistor for Q5 and also limits the current flow through Q5. R3 and R2 are used to set the current flow through Q1 and Q2. The ratio used to set the gain of the LM2412A. R1, R2 and R3 are all related when calculating the output voltage of the CRT driver. R limits the current through the base of Q2 ...

  • Page 5

    ... The DC TYPICAL APPLICATION A typical application of the LM2412A is shown in Figure 10 . Used in conjunction with three LM2202s, a complete video channel from monitor input to CRT cathode can be achieved. Performance is excellent for resolutions up to 1600 x 1200 and pixel clock frequencies at 200 MHz. Figure 10 is the ...

  • Page 6

    ... Note that the components are placed so that they almost line up from the output pin of the LM2412A to the blue cathode pin of the CRT connector. This is done to minimize the length of the video path between these two components. ...

  • Page 7

    Application Hints (Continued) 7 www.national.com ...

  • Page 8

    Application Hints (Continued) www.national.com FIGURE 11. PCB Top Layer 8 DS200124-13 ...

  • Page 9

    Application Hints (Continued) FIGURE 12. PCB Bottom Layer 9 DS200124-14 www.national.com ...

  • Page 10

    Application Hints (Continued) www.national.com FIGURE 13. PCB CRT Driver, Blue Channel Output DS200124-16 FIGURE 14. I and DS200124-15 IN ...

  • Page 11

    ... National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications. inches (millimeters) unless otherwise noted 11 Lead Molded TO-220 NS Package Number TA11B Order Number LM2412ATA 2. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system affect its safety or effectiveness ...