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LMH1981 Video Sync Separator

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The LMH1981 is a high-performance multi-format sync separator ideal for use in a wide range of video applications, such as broadcast and professional video equipment and HDTV/DTV systems. It provides composite sync, vertical sync, burst/back porch timing, and odd/even field detection.

 

Pin Description of LMH81:

Pin Number

Pin Name

Description

1

REXT

Bias Current External Resistor

2, 5, 10

GND

Ground

3,6, 11

VCC

Supply Voltage

4

VIN

Video-Input

7

HSOUT

Horizontal Sync Output

8

VSOUT

Vertical Sync Output

9

VFOUT

Video Format Output

12

CSOUT

Composite Sync Output

13

BPOUT

Burst/Back Porch Timing Output

14

OEOUT

Odd/Even Field Output

 

LMH1981 Specifications & Features:

  • Standard Analog Video Sync Separation for NTSC, PAL, 480I/P, 576I/P, 720P, and 1080I/P/PsF from Composite Video (CVBS), S-Video (Y/C), and Component Video (YPBPR/GBR) Interfaces
  • Operating Supply Voltage: 3.3V to 5V
  • Operating Supply Current: 11 mA
  • Bi-Level & Tri-Level Sync Compatible
  • Composite, vertical sync output
  • Odd/even field output
  •  Burst/back porch output
  • Available in 14-Pin PDIP and SOIC packages

 

Note: Complete Technical Details can be found at the LMH1981 datasheet given at the end of this page.

 

Equivalent for LMH1981: LM1881, EL4581

Alternatives Video sync separators:  EL1993, EL4583

  

Where to use the LMH1981 Video Sync Separator IC:

The LMH1981 has used a wide range of video applications, such as broadcast and professional video equipment and HDTV/DTV systems. One noticeable main application of the IC is to convert sync over composite videos (HSYNC + VSYNC + CVBS) into CSYNC video (HSYNC+VSYNC) by removing the composite video (CVBS) aspects. It provides composite sync, vertical sync, burst/back porch timing, and odd/even field detection. The LMH1981 automatically detects the input video format, eliminating the need for programming using a microcontroller.

So if you are looking for a composite video conversion IC, then LMH1981 might be of interest to you.

 

How to use LMH1981:

LMH1981 can work with the minimum number of components. The only required external components are bypass capacitors at the power supply pins, an input coupling capacitor at pin 4, and a precision REXT resistor at pin1. The typical connection diagram for LMH1981 is shown below.

LMH1981 Internal Circuit

The IC has an operating voltage from 3.3-5V. The VIN pin is fed with a low-noise, broadcast-quality signal over 75Ω coaxial cable. The coaxial cable should be impedance-matched with a 75Ω load termination resistor to prevent unwanted signal distortion. The output video which is free of composite and can be used on RGB monitors can be obtained from pin 8.

 

Applications of LMH1981:

  • Broadcast and Professional Video Equipment
  • HDTV/DTV Systems
  • Genlock Circuits
  • Video Capture Devices
  • Set-Top Boxes (STB) & Digital Video Recorders (DVR)
  • Video Displays

 

2D-Model of LMH1981 (PDSO):

Dimensions for LMH1981 IC is given below. These dimensions are for the PDSO package. If you are using different package IC please refer to the LMH1981 datasheet.

 LMH1981 Dimensions

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