Electronic Components Datasheet Search |
|
EL4583CN Datasheet(PDF) 8 Page - Intersil Corporation |
|
EL4583CN Datasheet(HTML) 8 Page - Intersil Corporation |
8 / 10 page 8 FN7173.3 November 12, 2010 Description of Operation A simplified block schematic is shown in Figure 1. The following description is intended to provide the user with sufficient information to understand the effects of the external components and signal conditions on the outputs of the integrated circuit. The video signal is AC coupled to pin 4 via the capacitor C1, nominally 0.1µF. The clamp circuit A1 will prevent the input signal on pin 4 going more negative than 1.5V, the value of reference voltage VR1. Thus the sync tip, the most negative part of the video waveform, will be clamped at 1.5V. The current source I1, nominally 6µA, charges the coupling capacitor during the remaining portion of the H line, approximately 58µs for a 15.75kHz timebase. From I • t = C • V, the video time-constant can be calculated. It is important to note that the charge taken from the capacitor during video must be replaced during the sync tip time, which is much shorter, (ratio of x 12.5). The corresponding current to restore the charge during sync will therefore be an order of magnitude higher, and any resistance in series with CI will cause sync tip crushing. For this reason, the internal series resistance has been minimized and external high resistance values in series with the input coupling capacitor should be avoided. The user can exercise some control over the value of the input time constant by introducing an external pull-up resistance from pin 4 to the 5V supply. The maximum voltage across the resistance will be VDD less 1.5V, for black level. For a net discharge current greater than zero, the resistance should be greater than 450k. This will have the effect of increasing the time constant and reducing the degree of picture tilt. The current source I1 directly tracks reference current ITR and thus increases with scan rate adjustment, as explained later. FIGURE 4. STANDARD (NTSC INPUT) H. SYNC DETAIL EL4583 |
Similar Part No. - EL4583CN |
|
Similar Description - EL4583CN |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.COM |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Datasheet Upload | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
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 |