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ELM304 Dataheets PDF



Part Number ELM304
Manufacturers ELM Electronics
Logo ELM Electronics
Description NTSC Video Generator
Datasheet ELM304 DatasheetELM304 Datasheet (PDF)

ELM304 NTSC Video Generator Description The ELM304 is a low-cost NTSC video signal generator in an 8 pin package. Requiring only an external crystal and a few passive components, this circuit produces a stable raster that is suitable for a variety of video applications. The ELM304 can be ‘programmed’ to generate either a solid white raster or a four-level gray scale pattern simply by changing the logic level at the mode input pin. A supplied internal pullup resistor further simplifies the circui.

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ELM304 NTSC Video Generator Description The ELM304 is a low-cost NTSC video signal generator in an 8 pin package. Requiring only an external crystal and a few passive components, this circuit produces a stable raster that is suitable for a variety of video applications. The ELM304 can be ‘programmed’ to generate either a solid white raster or a four-level gray scale pattern simply by changing the logic level at the mode input pin. A supplied internal pullup resistor further simplifies the circuitry when interfacing to mechanical switches. www.DataSheet4U.com Although originally designed to provide a stable video input signal for use while recording audio on video cassette recorders, this circuit can also be used for many other instructional and test purposes. The low power consumption and small size of the circuit also makes it ideal for battery-powered applications. Features • Low power CMOS design - typically 1mA at 5V • Wide supply range - 3.0 to 5.5 volt operation • Uses a standard 3.58MHz crystal • Generates both solid and bar type patterns • No external amplifier required • Standard 1V p-p NTSC sync negative output • Requires no adjustments Connection Diagram PDIP and SOIC (top view) VDD 1 2 3 4 8 7 6 5 VSS V1 V2 V3 Applications • Video Source for Video Cassette Recorders • Classroom Instructional Aid • Test Bench Video Generator XT1 XT2 Mode Block Diagram 7 V1 V2 V3 XT1 XT2 2 Master Oscillator 3 Pattern Generator Output Matrix 6 5 VDD Mode 4 ELM304DSB Elm Electronics – Circuits for the Hobbyist < http://www.elmelectronics.com/ > 1 of 4 ELM304 Pin Descriptions VDD (pin 1) This pin is the positive supply pin, and should always be the most positive point in the circuit. Internal circuitry connected to this pin is used to provide power on reset of the microprocessor, so an external reset signal is not required. Refer to the Electrical Characteristics section for further information. XT1 (pin 2) and XT2 (pin 3) A 3.579545MHz NTSC television colourburst crystal is connected between these two pins. Crystal loading capacitors (typically 27pF) will www.DataSheet4U.com also normally be connected between each of the pins and Vss. Mode (pin 4) The ELM304 can be selected to operate in one of two modes depending on the logic level on this pin. When at a high level (or open-circuited), the generated raster is solid white in colour. If this pin is held at a low level, the circuit will generate a four-level pattern of typically 100%, 60%, 40% and 20% white. V3, V2, and V1 (pins 5, 6, and 7) These are the digital to analog converter’s logic level output signals. When combined through a few appropriate resistors (see the example application section), a standard 1Vp-p NTSC video signal is created. Output levels during the signal phases are as follows: Signal Phase Sync Blanking 20% White 40% White 60% White 100% White V3 L L H L H H V2 L L L H L H V1 L H L H H H VSS (pin 8) Circuit common is connected to this pin. This is the most negative point in the circuit. Ordering Information These integrated circuits are available in either the 300 mil plastic DIP format, or in the 200 mil SOIC surface mount type of package. To order, add the appropriate suffix to the part number: 300 mil Plastic DIP............................... ELM304P 200 mil SOIC..................................... ELM304SM All rights reserved. Copyright ©1999 Elm Electronics. Every effort is made to verify the accuracy of information provided in this document, but no representation or warranty can be given and no liability assumed by Elm Electronics with respect to the accuracy and/or use of any products or information described in this document. Elm Electronics will not be responsible for any patent infringements arising from the use of these products or information, and does not authorize or warrant the use of any Elm Electronics product in life support devices and/or systems. Elm Electronics reserves the right to make changes to the device(s) described in this document in order to improve reliability, function, or design. ELM304DSB Elm Electronics – Circuits for the Hobbyist < http://www.elmelectronics.com/ > 2 of 4 ELM304 Absolute Maximum Ratings Storage Temperature....................... -65°C to +150°C Ambient Temperature with Power Applied....................................-40°C to +85°C Voltage on VDD with respect to VSS............ 0 to +7.5V Voltage on any other pin with respect to VSS........................... -0.6V to (VDD + 0.6V) Note: Stresses beyond those listed here will likely damage the device. These values are given as a design guideline only. The ability to operate to these levels is neither inferred nor recommended. Electrical Characteristics All values are for operation at 25°C and a 5V supply, unless otherwise noted. For further information, refer to note 1 below. www.DataSheet4U.com Characteristic Minimum 3.0 0.05 Typical 5.0 Maximum Units 5.5 V V/ms Conditions Supply Voltage, VDD VDD rate.


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