Overview
The LMH1981MT/NOPB, produced by Texas Instruments, is a high-performance multi-format video sync separator. This device is designed to extract timing information from various video formats, including NTSC, PAL, 480I/P, 576I/P, 720P, and 1080I/P/PsF, making it ideal for use in broadcast and professional video equipment, HDTV/DTV systems, and other video applications.
The LMH1981MT/NOPB operates from a supply voltage between 3.3V and 5V and is available in a 14-pin TSSOP package. It features automatic video format detection, bi-level and tri-level sync compatibility, and superior jitter performance on the leading edge of the horizontal sync output.
Key Specifications
| Parameter | Min | Typ | Max | Units |
|---|---|---|---|---|
| Supply Voltage (VCC) | 0 | - | 5.5 | V |
| Supply Current (ICC) at VCC = 3.3V | 9.5 | 11.5 | - | mA |
| Supply Current (ICC) at VCC = 5V | 11 | 13.5 | - | mA |
| Video Input Sync Amplitude for SD/EDTV bi-level sync | 0.14 | 0.30 | 0.60 | VPP |
| Video Input Sync Amplitude for HDTV tri-level sync | 0.30 | 0.60 | 1.20 | VPP |
| Horizontal Sync Output Propagation Delay | - | 30 | - | ns |
| Operating Temperature Range | -40 | - | 85 | °C |
Key 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)
- Bi-level and tri-level sync compatibility
- Automatic video format detection
- 50% sync slicing for video inputs from 0.5 VPP to 2 VPP
- Superior jitter performance on the leading edge of the horizontal sync output
- CMOS logic outputs for composite, horizontal, and vertical syncs, burst/back porch timing, odd/even field, and video format outputs
- 3.3V to 5V supply operation
- Available in a 14-pin TSSOP package
Applications
- Broadcast and professional video equipment
- HDTV/DTV systems
- Genlock circuits
- Video capture devices
- Set-top boxes (STB) and digital video recorders (DVR)
- Video displays
Q & A
- What is the primary function of the LMH1981MT/NOPB?
The LMH1981MT/NOPB is a multi-format video sync separator designed to extract timing information from various video formats.
- What video formats does the LMH1981MT/NOPB support?
The device supports NTSC, PAL, 480I/P, 576I/P, 720P, and 1080I/P/PsF video formats.
- What is the operating voltage range of the LMH1981MT/NOPB?
The device operates from a supply voltage between 3.3V and 5V.
- What is the significance of the REXT resistor in the LMH1981MT/NOPB?
The REXT external resistor establishes the internal bias current and precise reference voltage for the LMH1981, ensuring optimal performance.
- How does the LMH1981MT/NOPB handle jitter on the horizontal sync output?
The device features superior jitter performance on the leading edge of the horizontal sync output, minimizing external circuitry needed to clean and reduce jitter.
- What are the key outputs provided by the LMH1981MT/NOPB?
The outputs include composite, horizontal, and vertical syncs, burst/back porch timing, odd/even field, and video format outputs in CMOS logic.
- What is the recommended input termination for the LMH1981MT/NOPB?
The video source should be load terminated with a 75Ω resistor to ensure correct video signal amplitude and minimize signal distortion.
- How does the LMH1981MT/NOPB handle different sync levels?
The device is compatible with both bi-level and tri-level syncs and applies 50% sync slicing to ensure accurate sync extraction.
- What is the significance of the video format output in the LMH1981MT/NOPB?
The video format output conveys the total horizontal line count per field as an 11-bit binary serial data stream, enabling dynamic adjustment of system parameters.
- What are some common applications of the LMH1981MT/NOPB?
Common applications include broadcast and professional video equipment, HDTV/DTV systems, genlock circuits, video capture devices, set-top boxes, and digital video recorders.
