National Semiconductor LMH1980 Data Handbook
Summary
This auto-detecting video sync separator is designed to reliably separate SD/HD/PC analog video timing signals (Composite, Horizontal, Vertical Sync) automatically across various formats (NTSC, PAL). Ideal for professional applications—including automotive monitors, surveillance systems, machine vision, and professional video capture equipment—the unit provides clean, accurate timing outputs regardless of the sync level or standard used. The manual details installation, electrical specifications, and optimized integration into complex digital video processing systems.
Page 1 Text Content
to -D te tin /H /P id ra to
July 2007
LMH1980 Auto-Detecting SD/HD/PC Video Sync Separator General Description Features The LMH1980 is an auto-detecting SD/HD/PC video sync Analog video sync separation for NTSC, PAL, 480I/P, separator ideal for use in a wide range of video applications, 576I/P, 720P, 1080I/P/Ps F, and many VESA-compatible such as automotive LCD monitors, video capture & editing timing formats devices, surveillance & security equipment, and machine vi- Composite Video (CVBS), S-Video (Y/C), and Component sion and inspection systems. Video (YPBPR/GBR) and PC Graphics (RGs B) interfaces The LMH1980 accepts an analog video input signal with ei- SD/PC Bi-level sync & HD tri-level sync compatible ther bi-level or tri-level sync and automatically detects the
Composite, Horizontal, and Vertical Sync outputs
video format, eliminating the need for external RSET resistor
Burst/Back Porch Timing, Odd/Even Field, and HD Detect
adjustment required by other sync separators (e.g.: LM1881).
Flag outputs
The outputs provide timing signals in CMOS logic, including
Automatic video format detection
Composite, Horizontal, and Vertical Syncs, Burst/Back Porch
Timing, and Odd/Even Field outputs. The HD flag output (pin Fixed-level sync slicing for video inputs from 0.5 to 2 VPP
5) provides a logic low signal only when a valid HD video input 3.3V to 5V supply operation with tri-level sync is detected. The HD flag can be used to disable an external switch-controlled SD chroma filter when
Applications
HD video is detected, or enable it when SD video is detected.
Consumer, Professional, Automotive & Industrial Video
For non-standard video with bi-level sync and without vertical
serration pulses, a default vertical sync pulse will be output Video Capture, Editing, and Processing
and no horizontal sync pulses will be output during the vertical
Genlock Circuits
sync interval.
Surveillance & Security Video Systems
The LMH1980 is available in a space-saving 10-ld. Mini-SO
Set-Top Boxes (STB) & Digital Video Recorders (DVR)
Package (MSOP) and operates over a temperature range of
LCD / Plasma Displays and Video Projectors
−40°C to +85°C.
Machine Vision and Inspection Systems Video Trigger Oscilloscopes and Waveform Monitors
Connection Diagram Pin Descriptions
Pin No. Pin Name Pin Description
10-ld. MSOP
REXT Bias Current External Resistor GND Ground VCC Supply Voltage VIN Analog Video Input HD HD Detect Flag Output HSOUT Horizontal Sync Output VSOUT Vertical Sync Output CSOUT Composite Sync Output
Top View
BPOUT Burst/Back Porch Timing Output OEOUT Odd/Even Field Output
FIGURE 1. Pinout
Ordering Information Package Part Number Package Marking Transport Media NSC Drawing
LMH1980MM 1k Units Tape and Reel
10-ld. MSOP AL4A MUB10A
LMH1980MMX 3.5k Units Tape and Reel
© 2007 National Semiconductor Corporation www.national.com
Page Summary Contents For National Semiconductor LMH1980 Data Handbook
Manual Details
| Brand | National |
|---|---|
| Pages | 14 |
| File Size | 746.61 KB |
| Published | June 04, 2026 |
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Frequently Asked Questions
What types of video formats does the LMH1980 support?
It supports detection for NTSC, PAL, 480I/P, 576I/P, and up to 1080I/P, working with SD/HD/PC video sync.
Does this separator require external timing adjustments?
No, the LMH1980 automatically detects the Composite, Horizontal, and Vertical Sync outputs, removing the need for external resistor or timing set adjustments.
What specific types of electrical syncing signals can it accept?
It accepts analog video input with SD/PC Bi-level sync and HD tri-level sync compatibility.
What is the operational temperature range for this device?
The recommended operating temperature range for the LMH1980 is from -40°C to +85°C.