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Home > Products > Integrated Circuits (ICs) > Linear > Video Processing

Texas Instruments LM1881N/NOPB

Name: LM1881N/NOPB
Brand: Texas Instruments
SKU: LM1881N/NOPB
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: LM1881N/NOPB

Manufacturer:: Texas Instruments

Category:: Video Processing

Package:: 8-DIP (0.300", 7.62mm)

Datasheet:: LM1881N/NOPB.pdf

Description:: LM1881 VIDEO SYNC SEPARATOR

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Product details

Overview

LM1881N/NOPB from Texas Instruments (formerly National Semiconductor) is a video sync separator IC that extracts composite sync, vertical sync, burst/back porch, and odd/even field timing signals from NTSC, PAL, and SECAM composite video inputs (0.5–2 V_p-p). It operates from 5–12 V supply, delivers <10 mA supply current, and supports horizontal scan rates up to 150 kHz - used in broadcast monitoring, video line selection, and frame memory systems.

For engineers reviewing the LM1881N/NOPB datasheet, LM1881N/NOPB pinout, LM1881N/NOPB application, or LM1881N/NOPB equivalent, this page provides verified sync separation parameters, vertical default timing behavior, RSET-dependent pulse width control, and real-world video line selection implementation guidance.

Technical Context

The LM1881N/NOPB uses internal clamping and comparator-based threshold detection (70 mV typical) to isolate sync tips from AC-coupled composite video. Its integrator circuit-charged via external RSET resistor at Pin 6-generates vertical sync on the rising edge of the first serration pulse, with edge-triggered output at Pin 3.

A secondary default vertical output activates if no serration occurs within programmable delay (32–90 µs), enabling robust operation with non-standard video sources like home computers. The odd/even field output (Pin 7) toggles per interlaced field by detecting equalizing pulse timing differences, while burst gate (Pin 5) provides a 2.5–4.7 µs pulse aligned to back porch timing for chroma recovery or DC restoration.

Key Specifications

Parameter	Value and Actual Design Meaning
Supply Voltage Range	5 V to 12 V DC - single-supply operation compatible with standard video system rails.
Input Signal Range	0.5 V to 2 V_p-p - accommodates standard broadcast and consumer video amplitudes without attenuation or gain stages.
Horizontal Rate Support	Up to 150 kHz - enables use with VGA and high-line-count computer video formats beyond NTSC/PAL.
Vertical Sync Width	190–300 µs - matches NTSC vertical blanking interval duration and supports precise line counting.
Burst Gate Width	2.5–4.7 µs - aligns with standard chroma burst duration for reliable subcarrier synchronization.
Vertical Default Delay	32–90 µs - programmable via RSET to handle long vertical intervals in non-broadcast video sources.
Input Resistance	>10 kΩ - minimizes loading on upstream video source, preserving signal integrity in daisy-chained systems.
Supply Current	5.2–12 mA - low quiescent draw suitable for power-constrained embedded video subsystems.

Pinout & Package

Molded Dual-In-Line Package (DIP-8), NS Package Number N08E, through-hole mounting, 0°C to +70°C operating range.

Pin/Terminal	Circuit Role	Design Meaning
1	Composite Sync Output	Clamped, noise-filtered replica of sync tip waveform - used as timing reference for genlock or sync stripping.
2	AC-Coupled Video Input	High-impedance input accepting 0.5–2 V_p-p composite video; internal clamp sets DC level to 1.5 V.
3	Vertical Sync Output	Edge-triggered pulse starting at first vertical serration rising edge - enables precise line counting in vertical blanking interval.
4	GND	Signal and power ground reference for all internal comparators and integrator.
5	Burst Gate / Back Porch Output	4.7 µs max pulse aligned to back porch - drives chroma extraction or black-level clamp circuits.
6	RSET	External resistor (680 kΩ typical) setting integrator charge current and internal oscillator frequency.
7	Odd/Even Field Output	Logic-high during odd field, low during even field - identifies interlaced field order for frame memory addressing.
8	VCC	Positive supply input (5–12 V); decoupling capacitor required for stable sync separation.

Key Features

Feature	Design Value
Edge-triggered vertical sync	Starts precisely at rising edge of first vertical serration - eliminates jitter in line-counting applications.
Default vertical output mode	Activates after programmable delay (RSET-dependent) for non-standard video - ensures sync continuity with game consoles and PC video.
Four independent timing outputs	Composite sync, vertical sync, burst gate, and odd/even field - enables full video timing reconstruction from one IC.
RSET-programmable timing	Single external resistor adjusts vertical pulse width (180–340 µs) and default delay (32–90 µs) - simplifies design across NTSC, PAL, and VGA.
Interlaced field identification	Digital odd/even flag derived from equalizing pulse timing - supports correct field-order storage in dual-field frame buffers.
Back porch-aligned burst gate	2.5–4.7 µs pulse synchronized to chroma burst location - enables clean subcarrier recovery without external timing logic.

Applications

Broadcast Monitoring System	Video Line Selector
Use Scenario: Real-time analysis of analog video signals in broadcast engineering trucks to verify sync integrity and detect timing anomalies. IC Role / Device Role / Timing Role: LM1881N/NOPB acts as primary sync extractor, delivering isolated composite sync and vertical pulses to measurement instruments. Use Value: Enables accurate measurement of horizontal/vertical interval timing deviations down to ±1 µs using its edge-triggered vertical output and low-jitter composite sync.	Use Scenario: Selecting specific scan lines (e.g., line 17 or 21) from composite video for closed caption or teletext data insertion. IC Role / Device Role / Timing Role: LM1881N/NOPB provides the vertical sync start reference and composite sync transitions needed to count lines from vertical blanking interval. Use Value: Allows deterministic line selection using simple counters triggered by LM1881N/NOPB's vertical pulse falling edge and composite sync edges - no FPGA or microcontroller required.
Frame Memory Controller	Legacy Video Equipment Interface
Use Scenario: Managing dual-field video frame buffers in professional video processors handling interlaced NTSC/PAL sources. IC Role / Device Role / Timing Role: LM1881N/NOPB supplies odd/even field flag and vertical sync to coordinate write/read addressing across two memory banks. Use Value: Eliminates field-order misalignment errors by providing synchronous, hardware-generated field index tied directly to video source timing.	Use Scenario: Integrating vintage video game consoles or early PC graphics adapters into modern test setups requiring clean sync signals. IC Role / Device Role / Timing Role: LM1881N/NOPB serves as adaptive sync separator, using default vertical mode when non-standard vertical intervals occur. Use Value: Maintains stable sync output even with irregular vertical timing (e.g., CGA/EGA signals), avoiding display lockup or field tearing.

Broadcast Monitoring System

Video Line Selector

Use Scenario: Real-time analysis of analog video signals in broadcast engineering trucks to verify sync integrity and detect timing anomalies.

IC Role / Device Role / Timing Role: LM1881N/NOPB acts as primary sync extractor, delivering isolated composite sync and vertical pulses to measurement instruments.

Use Value: Enables accurate measurement of horizontal/vertical interval timing deviations down to ±1 µs using its edge-triggered vertical output and low-jitter composite sync.

Use Scenario: Selecting specific scan lines (e.g., line 17 or 21) from composite video for closed caption or teletext data insertion.

IC Role / Device Role / Timing Role: LM1881N/NOPB provides the vertical sync start reference and composite sync transitions needed to count lines from vertical blanking interval.

Use Value: Allows deterministic line selection using simple counters triggered by LM1881N/NOPB's vertical pulse falling edge and composite sync edges - no FPGA or microcontroller required.

Frame Memory Controller

Legacy Video Equipment Interface

Use Scenario: Managing dual-field video frame buffers in professional video processors handling interlaced NTSC/PAL sources.

IC Role / Device Role / Timing Role: LM1881N/NOPB supplies odd/even field flag and vertical sync to coordinate write/read addressing across two memory banks.

Use Value: Eliminates field-order misalignment errors by providing synchronous, hardware-generated field index tied directly to video source timing.

Use Scenario: Integrating vintage video game consoles or early PC graphics adapters into modern test setups requiring clean sync signals.

IC Role / Device Role / Timing Role: LM1881N/NOPB serves as adaptive sync separator, using default vertical mode when non-standard vertical intervals occur.

Use Value: Maintains stable sync output even with irregular vertical timing (e.g., CGA/EGA signals), avoiding display lockup or field tearing.

Equivalent & Alternatives

The following parts are listed as comparable options for similar video sync separation applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
MAX9586ESA+	Single 3.3 V supply; integrated 50 Ω driver; no RSET programming; fixed 15.734 kHz NTSC optimization.	Limited to standard-definition broadcast video; lacks default vertical mode and odd/even field output.	Select MAX9586ESA+ only for cost-sensitive, 3.3 V-only designs where NTSC compliance and minimal BOM are priorities.
EL4583CSZ	Wideband video amplifier + sync stripper; requires external comparator and timing logic; higher supply current (25 mA).	Offers greater flexibility in custom sync processing but increases design complexity and board area.	Choose EL4583CSZ when custom sync filtering, variable threshold, or multi-format adaptability outweighs integration and power advantages of LM1881N/NOPB.

Compared with MAX9586ESA+ and EL4583CSZ, the LM1881N/NOPB uniquely combines RSET-programmable timing, hardware-based odd/even field detection, and default vertical mode - making it the only option supporting both broadcast standards and non-standard video sources without external logic.

Availability

LM1881N/NOPB is available at Aetrix Electronics and suitable for broadcast monitoring, video line selection, and legacy video interface applications requiring stable component supply, long-term obsolescence management, and RoHS-compliant through-hole packaging.

Supply support for LM1881N/NOPB includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments acquired National Semiconductor in 2011 and maintains full technical support, datasheets, and legacy product availability for the LM1881N/NOPB.

The LM1881N/NOPB belongs to TI's legacy video interface product line, designed specifically for analog video timing extraction in broadcast, instrumentation, and industrial video systems - emphasizing reliability, wide input amplitude tolerance, and hardware-based timing accuracy.

FAQ

What is the function of Pin 6 (RSET) on the LM1881N/NOPB?

Pin 6 (RSET) on the LM1881N/NOPB sets the internal integrator charge current and oscillator frequency. A 680 kΩ resistor yields nominal NTSC timing (180 µs vertical pulse, ~50 µs default delay). Increasing RSET extends both vertical pulse width and default delay - critical for adapting LM1881N/NOPB to PAL, VGA, or non-standard video sources.

Does the LM1881N/NOPB support PAL video signals?

Yes, the LM1881N/NOPB explicitly supports PAL video signals as stated in its General Description and Applications section. Its sync separation architecture handles PAL's 50 Hz field rate and longer vertical interval, and RSET adjustment allows tuning vertical pulse width to match PAL timing - confirmed by electrical characteristics tested across 0°C to +70°C.

How does the LM1881N/NOPB generate the odd/even field output on Pin 7?

The LM1881N/NOPB generates the odd/even field output on Pin 7 by comparing integration timing between equalizing pulses in the vertical blanking interval. During odd fields, the half-line offset shifts the equalizing pulse timing, causing the internal flip-flop to toggle polarity - resulting in Pin 7 high for odd fields and low for even fields, as verified in Figure 1(d) and Application Notes.

Can the LM1881N/NOPB operate from a 3.3 V supply?

No, the LM1881N/NOPB requires a minimum 5 V supply, with Absolute Maximum Ratings specifying 13.2 V and Electrical Characteristics tested at 5 V and 12 V. Operation below 5 V is not characterized or guaranteed - attempting 3.3 V will result in failure to produce valid sync outputs due to insufficient headroom for internal comparator thresholds and output drive.

What is the purpose of the default vertical output in the LM1881N/NOPB?

The default vertical output in the LM1881N/NOPB activates when no serration pulse occurs within the RSET-programmed time window - ensuring continuous vertical sync generation for non-standard video sources like home computers or early PC graphics. This feature prevents loss of vertical timing during irregular vertical intervals, as documented in the General Description and Vertical Sync Output section.

LM1881N/NOPB Specifications

Product attributes: Attribute value

Manufacturer:: Texas Instruments

Series:: -

Package/Case:: 8-DIP (0.300", 7.62mm)

Packaging:: Bulk

Product Status:: Active

Function:: Separator

Applications:: Professional Video

Standards:: NTSC, PAL, SECAM

Control Interface:: -

Voltage - Supply:: 13.2V

Mounting Type:: Through Hole

Grade:: -

Qualification:: -

Supplier Device Package:: 8-PDIP

LM1881N/NOPB FAQ

1.How can I place an order for LM1881N/NOPB through Aetrix?

Please submit a Request for Quotation (RFQ) for LM1881N/NOPB on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for LM1881N/NOPB reliable?

The price and inventory of LM1881N/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM1881N/NOPB is usually 5 days.

3.What payment methods are accepted for LM1881N/NOPB?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM1881N/NOPB transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for LM1881N/NOPB?

LM1881N/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your LM1881N/NOPB order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for LM1881N/NOPB?

For technical support, including LM1881N/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM1881N/NOPB requirements.

6.How does Aetrix verify that LM1881N/NOPB is sourced from the original manufacturer or authorized distributors?

All LM1881N/NOPB products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LM1881N/NOPB meets industry standards.

7.What is the process for return or replacement of LM1881N/NOPB?

All LM1881N/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM1881N/NOPB, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The LM1881N/NOPB part is unused and in its original packaging.

Return procedure for LM1881N/NOPB:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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