Part # Application Note Television ST92185 ST92195 ST92T195 8-bit MCU for TV AN1844 datasheet

Part Manufacturer: ST Microelectronics

ST Microelectronics

Part Description: PCB Compatibility using ST92185/195 in SDIP42/56 packages


Part Details:

AN1844 APPLICATION NOTE PCB compatibility using ST92185/195 in SDIP42/56 packages 1 INTRODUCTIONThe purpose of this note is to: 1. Describe how to design a printed circuit board to be compatible between ST92185, ST92195 and ST92T195 devices in both SDIP42 & SDIP56 packages. 2. Provide an overview of the ST92195 family available in SDIP56 package and the ST92185 device family available in SDIP42 and SDIP56 packages. 3. Describe the R,G,B,FB outputs and the teletext clock external filter needed for the ST92185/195 devices family. 2 SDIP42/56 MOUNTING COMPATIBILITYTo develop a circuit board in which either a 56 pins or 42 pins ST92185/195 can be installed,you must provide configurable necessary locations for installing the external components asdescribed in paragraphs below. 2.1 SDIP56 MOUNTING INSTRUCTIONS All devices in the ST92185/195 family are available in the SDIP56 package. The ST92T195 (OTP device) is only available in the SDIP56 package. (Refer to chapter 4 for an overview of package availability) 2.1.1 MCFM filter The MCFM pin (27) is the external PLL filter for the main clock. This filter, composed of 3 com-ponents must be as close as possible to the device for good clock stability. The JTRST0 pin(37) is for test purposes and must be tied to GND. Because the MCFM on the ST92185 SDIP42 package corresponds to pin 37 it must beplanned, for the reasons of clock stability mentioned before, to provide mounting holes for theMCFM filter next to pin 37 and a strap to GND for JTRST0 as shown in Figure 1. and Figure 2. 2.1.2 TXCF filter The TXCF pin (29) is the external PLL filter for the slicer clock. This filter, composed of 3 com-ponents must be as close as possible to the device for good clock stability as shown in Figure1. Because slicing features do not exist on the ST92185 device, external filter components canbe removed (TXCF pin is Not Connected in this product) as shown in Figure 2. Rev. 2 AN1844/0704 1/9 AN1844 - APPLICATION NOTE 2.1.3 CVBS1 & CVBS2 input pins The CVBS1 and CVBS2 inputs are used to forward the composite video signal to the Teletext/VPS slicer and the WSS slicer respectively. Each coupling capacitor cuts the DC compositeof the video signal as shown in Figure 1. Because slicing features do not exist on the ST92185 device, external capacitors can be re-moved (CVBS1 and CVBS2 pins are Not Connected in this product) as shown in Figure 2. Figure 1. SDIP56 Mounting for ST92T195, ST92195 1 56 2 55 3 54 4 53 5 52 6 OSCIN 51 7 OSCOUT 50 8 49 9 48 10 47 11 46 12 45


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Application Note Television ST92185 ST92195 ST92T195 8-bit MCU for TV AN1844.pdf Datasheet