LMH1981

Multi-Format Video Sync Separator

General Description

The LMH1981 is a high performance multi-format sync sepa-

rator ideal for use in a wide range of video applications, such

as broadcast and professional video equipment and HDTV/

DTV systems.

The input accepts standard analog video signals with either

bi-level or tri-level sync, and the outputs provide all of the

critical timing signals in CMOS logic, including composite,

horizontal, and vertical syncs, burst/back porch timing, odd/

even field, and video format outputs. The horizontal sync

output features very low jitter, minimizing external circuitry

needed to clean and reduce jitter in subsequent sync pro-

cessing stages.

The LMH1981 automatically detects the input video format,

eliminating the need for programming using a microcontroller

or external R

50% sync slicing to ensure accurate sync extraction for

inputs with irregular amplitude, offset, and noise conditions.

Its unique video format feature (pin 9) outputs the total

vertical scan lines per frame as an 11-bit binary serial bit

stream, which can be decoded by the video system to de-

termine the input video format and enable dynamic adjust-

ment of system parameters, i.e.: color space or scaler con-

versions. The LMH1981 is available in a 14-pin TSSOP

package and operates over the full commercial temperature

range.

Features

n

Standard analog video sync separation for NTSC, PAL,

SECAM, 480i/p, 576i/p, 720p, 1080i/p, and RGsB from

composite (CVBS), S-Video (Y/C), component (YP

and computer video interfaces

n

Bi-level & tri-level sync compatible

n

Composite, horizontal, and vertical sync outputs

n

Burst/back porch timing, odd/even field, and video

format Outputs

n

Superior jitter performance on the H Sync

negative-going edge reference

n

Automatic video format detection

n

50% sync slicing of video inputs from 0.5 V

n

Macrovision compatible

n

3.3V to 5V supply operation

Applications

n

Broadcast and professional video equipment

n

HDTV/DTV systems

n

Genlock systems

n

Video capture & digitization

n

Set-top boxes (STB) & digital video recorders (DVR)

n

Video displays

Connection Diagram

Pin Descriptions

Pin No.

Pin Name

Pin Description

1R

EXT

Bias Current External Resistor

2, 5, 10

GND

Ground

3, 6, 11

V

CC

Supply Voltage

4V

IN

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

Ordering Information

Package

Part Number

Package Marking

Transport Media

NSC Drawing

14-Pin TSSOP

LMH1981MT

LMH1981MT

94 Units/Rail

MTC14

LMH1981MTX

2.5k Units Tape and Reel

14-Pin TSSOP

20174501

Top View

FIGURE 1. Pinout

PRELIMINARY

April 2006

© 2006 National Semiconductor Corporation

DS201745

www.national.com