ELM304

Elm Electronics – Circuits for the Hobbyist

< http://www.elmelectronics.com/ >

Connection Diagram

PDIP and SOIC

(top view)

1

2

3

4

8

7

6

5

NTSC Video Generator

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.

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.

• 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

• Video Source for Video Cassette Recorders

• Classroom Instructional Aid

• Test Bench Video Generator

V3

V2

V1

XT1

Description

Applications

Block Diagram

1 of 4

Features

ELM304DSB

XT2

Mode

2

3

4

6

7

5

V3

V2

V1

Mode

XT1

XT2

Master

Oscillator

Pattern

Generator

Output

Matrix