Electronic Components Datasheet Search |
|
FMS6346 Datasheet(PDF) 6 Page - Fairchild Semiconductor |
|
FMS6346 Datasheet(HTML) 6 Page - Fairchild Semiconductor |
6 / 11 page www.fairchildsemi.com 6 FMS6346 Rev. 1B Applications Information Functional Description The FMS6346 Low Cost Video Filter (LCVF) provides 6dB gain (9dB optional, contact factory for further information) from input to output. In addition, the input will be slightly offset to optimize the output driver performance. The offset is held to the minimum required value to decrease the standing DC current into the load. Typical voltage levels are shown in the diagram below. Figure 9. Typical Voltage Levels The FMS6346 provides an internal diode clamp to support AC- coupled input signals. If the input signal does not go below ground, the input clamp will not operate. This allows DAC out- puts to directly drive the FMS6346 without an AC coupling capacitor. The worst-case sync tip compression due to the clamp will not exceed 7mV. The input level set by the clamp combined with the internal DC offset will keep the output within its acceptable range. When the input is AC-coupled, the diode clamp will set the sync tip (or lowest voltage) just below ground. For symmetric signals like C, U, V, Cb, Cr, Pb and Pr, the aver- age DC bias is fairly constant and the inputs can be AC-coupled with the addition of a pull-up resistor to set the DC input voltage. DAC outputs can also drive these same signals without the AC coupling capacitor. A conceptual illustration of the input clamp circuit is shown below: Figure 10. Input Clamp Circuit I/O Configurations For DC-coupled DAC drive with DC-coupled outputs, use this configuration: Figure 11. DC-coupled Inputs and Outputs Alternatively, if the DAC’s average DC output level causes the signal to exceed the range of 0V to 1.4V, it can be AC-coupled as follows: Figure 12. AC-coupled Inputs, DC-coupled Outputs When the FMS6346 is driven by an unknown external source or a SCART switch with its own clamping circuitry, the inputs should be AC-coupled as follows: Figure 13. SCART Configuration with DC-coupled Outputs There will be a 280mV offset from the DC input level to the DC output level. VOUT = 2 * VIN + 280mV 0.0 -> 0.02V 0.3 -> 0.32V 0.65 -> 0.67V 1.0 -> 1.02V VIN 0.28V 0.88V 1.58V 2.28V Driven by: DC-Coupled DAC Outputs AC-Coupled and Clamped Y, CV, R, G, B VOUT 0.15V 0.5V 0.85V VIN 0.58V 1.28V 1.98V Driven by: AC-Coupled and Biased U, V, Pb, Pr, C VOUT DVD or STB SoC DAC Output 75 Ω LCVF Clamp Inactive 0V - 1.4V DVD or STB SoC DAC Output LCVF Clamp Active 0.1u 0V - 1.4V 75 Ω 75 Ω LCVF Clamp Active 0.1u External Video source must be AC-coupled. 0V - 1.4V 75 Ω YOUT Driver YIN 0.65V 800k Ω |
Similar Part No. - FMS6346 |
|
Similar Description - FMS6346 |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.NET |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | 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 |