LMH1981 Video Sync Separator

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:

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.

The IC has an operating voltage from 3.3-5V. The V_IN 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.