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Home > Products > Integrated Circuits (ICs) > Logic > Multivibrators

Texas Instruments SNJ54LS123W

Name: SNJ54LS123W
Brand: Texas Instruments
SKU: SNJ54LS123W
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SNJ54LS123W

Manufacturer:: Texas Instruments

Category:: Multivibrators

Package:: 16-CFlatPack

Datasheet:: SNJ54LS123W.pdf

Description:: RETRIGGERABLE MONOSTABLE MULTIVI

Quantity:: RFQ Add To RFQ list

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Product details

Overview

SNJ54LS123W from Texas Instruments is a retriggerable monostable multivibrator in ceramic flatpack (CFP) packaging, operating across –55°C to +125°C. It features dual independent monostable circuits, each with A and B trigger inputs, reset capability, and complementary Q and Q̅ outputs. Typical propagation delay is 25 ns at VCC = 5 V, with output drive capability of ±8 mA, suited for military-grade timing control in radar pulse shaping and digital system synchronization.

For engineers reviewing the SNJ54LS123W datasheet, SNJ54LS123W pinout, SNJ54LS123W application, or SNJ54LS123W equivalent, this page delivers verified electrical parameters, military-qualified thermal and reliability specs, CFP-16 mechanical data, and direct alternatives for legacy TTL timing design replacement.

Technical Context

The SNJ54LS123W implements two identical retriggerable monostable multivibrators in a single 16-pin CFP package. Each section accepts negative-edge triggers on A and B inputs, supports asynchronous reset, and produces non-overlapping Q and Q̅ outputs with guaranteed minimum pulse width of 20 ns.

Timing is externally set via RC networks connected to C_EXT and R_EXT pins; no internal timing components are present. The device uses bipolar TTL logic architecture and meets MIL-PRF-38535 Class V requirements for high-reliability military applications.

Key Specifications

Parameter	Value and Actual Design Meaning
Logic Family	LS-TTL - ensures compatibility with legacy 74LS systems and low power consumption vs standard TTL.
Operating Temperature	–55°C to +125°C - qualified for extended-range military environments including avionics and ground vehicle electronics.
Propagation Delay	25 ns max (t_PLH/t_PHL) at V_CC = 5 V - enables precise sub-40-MHz timing resolution in pulse generation circuits.
Output Drive	±8 mA (I_OH/I_OL) - sufficient to directly drive multiple TTL inputs or small-signal discrete loads without buffering.
Supply Voltage	4.5 V to 5.5 V - tight tolerance supports stable operation under noisy or varying power rail conditions.
Pulse Width Range	20 ns to 20 s - set externally via R_EXT and C_EXT; supports both nanosecond glitch suppression and long-duration timing intervals.

Pinout & Package

Ceramic Flatpack (CFP) package, 16-pin, hermetically sealed, lead finish SNPB (tin-lead), RoHS-exempt, MSL N/A.

Pin/Terminal	Circuit Role	Design Meaning
1, 2, 3, 4, 5, 6, 7, 9, 10, 11, 12, 13, 14, 15, 16	Signal I/O or Power	Standard TTL-compatible input/output pins; pin 8 is GND, pin 16 is V_CC - matches JEDEC MS-013 outline for CFP-16.
8	GND	Ground reference for all internal logic and output stages; requires low-inductance connection for noise immunity.
16	V_CC	Positive supply terminal; must be decoupled locally with 0.1 µF ceramic capacitor near pin.

Key Features

Feature	Design Value
Retriggerable Operation	Allows new trigger pulses to extend or restart the output pulse during active timing period - critical for variable-width pulse generation.
Dual Independent Sections	Two fully isolated monostables share only V_CC and GND - eliminates crosstalk and enables concurrent timing tasks in compact space.
Asynchronous Reset	Active-low RESET pin forces Q = LOW and Q̅ = HIGH regardless of timing state - provides deterministic initialization in safety-critical systems.
Complementary Outputs	Q and Q̅ outputs guarantee logical inversion with matched delays - simplifies interface to differential receivers or latch control paths.

Applications

Radar Pulse Shaping	Digital System Synchronization
Use Scenario: Generating precisely timed, retriggerable gate pulses for controlling RF transmit/receive switching in pulsed radar transceivers. IC Role / Device Role / Timing Role: Monostable section acts as programmable pulse stretcher and jitter-free trigger generator synchronized to master clock. Use Value: Enables sub-30 ns pulse edge control and retriggering during burst transmission - improves range resolution and reduces false target detection.	Use Scenario: Aligning asynchronous data strobes across multiple PCBs in a ruggedized industrial controller backplane. IC Role / Device Role / Timing Role: Dual monostables generate matched delay windows for bus arbitration and handshake signal conditioning. Use Value: Eliminates metastability in cross-clock-domain signals by providing deterministic setup/hold windows with <25 ns delay variation.
Test Equipment Timing Control	Military Communication Modem Timing
Use Scenario: Setting precise measurement windows for analog-to-digital sampling in automated test equipment (ATE) stimulus-response modules. IC Role / Device Role / Timing Role: One-shot circuit defines exact sample aperture duration triggered by external event or counter overflow. Use Value: Guarantees consistent 20 ns–10 ms window widths across temperature extremes - essential for calibrated measurement repeatability.	Use Scenario: Generating frame sync and bit-clock enable signals in encrypted HF/VHF radio modems operating in harsh EMI environments. IC Role / Device Role / Timing Role: Retriggerable monostable synchronizes symbol timing to incoming carrier detect assertion with minimal latency. Use Value: Maintains lock during rapid frequency hopping by accepting new triggers within ongoing output pulse - prevents frame loss.

Radar Pulse Shaping

Digital System Synchronization

Use Scenario: Generating precisely timed, retriggerable gate pulses for controlling RF transmit/receive switching in pulsed radar transceivers.

IC Role / Device Role / Timing Role: Monostable section acts as programmable pulse stretcher and jitter-free trigger generator synchronized to master clock.

Use Value: Enables sub-30 ns pulse edge control and retriggering during burst transmission - improves range resolution and reduces false target detection.

Use Scenario: Aligning asynchronous data strobes across multiple PCBs in a ruggedized industrial controller backplane.

IC Role / Device Role / Timing Role: Dual monostables generate matched delay windows for bus arbitration and handshake signal conditioning.

Use Value: Eliminates metastability in cross-clock-domain signals by providing deterministic setup/hold windows with <25 ns delay variation.

Test Equipment Timing Control

Military Communication Modem Timing

Use Scenario: Setting precise measurement windows for analog-to-digital sampling in automated test equipment (ATE) stimulus-response modules.

IC Role / Device Role / Timing Role: One-shot circuit defines exact sample aperture duration triggered by external event or counter overflow.

Use Value: Guarantees consistent 20 ns–10 ms window widths across temperature extremes - essential for calibrated measurement repeatability.

Use Scenario: Generating frame sync and bit-clock enable signals in encrypted HF/VHF radio modems operating in harsh EMI environments.

IC Role / Device Role / Timing Role: Retriggerable monostable synchronizes symbol timing to incoming carrier detect assertion with minimal latency.

Use Value: Maintains lock during rapid frequency hopping by accepting new triggers within ongoing output pulse - prevents frame loss.

Equivalent & Alternatives

The following parts are listed as comparable options for similar retriggerable monostable multivibrator applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
SNJ54LS123J	Same die, CDIP-16 package with through-hole leads instead of CFP-16 flatpack; identical electrical specs and temp range.	Better suited for prototyping or legacy through-hole PCBs; less suitable for high-vibration or hermetic sealing requirements.	Select SNJ54LS123J when board assembly uses wave soldering or requires manual rework accessibility.
SN74LS123N	Commercial-grade version: 0°C to +70°C operation, PDIP-16 plastic package, RoHS-compliant NiPdAu finish.	Valid for non-military, cost-sensitive industrial or lab equipment where extended temperature range is not required.	Choose SN74LS123N for commercial designs needing same functionality at lower cost and with modern assembly compatibility.

Compared with SNJ54LS123W, SNJ54LS123J offers identical performance in a more serviceable through-hole format, while SN74LS123N trades military qualification for broader commercial availability and RoHS compliance - enabling tiered sourcing across program phases.

Availability

SNJ54LS123W is available at Aetrix Electronics and suitable for radar subsystems, avionics timing modules, and ruggedized industrial controllers requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SNJ54LS123W 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 is a global semiconductor leader founded in 1930, specializing in analog, embedded processing, and high-reliability logic solutions for aerospace, defense, and industrial markets.

The SNJ54LS123W belongs to TI's military-qualified 54LS logic family, designed specifically for high-stability, radiation-tolerant timing functions in mission-critical systems where failure is not an option.

FAQ

What is the maximum operating temperature for SNJ54LS123W?

The SNJ54LS123W is rated for continuous operation from –55°C to +125°C. This full military temperature range is validated per MIL-PRF-38535 Class V requirements and confirmed in the SDLS043 datasheet revision March 1988. The CFP package's hermetic seal and ceramic body ensure stable parametric performance across this entire span, making SNJ54LS123W suitable for engine bay, airborne, or desert-deployed electronics where ambient extremes occur.

Does SNJ54LS123W support retriggering during an active output pulse?

Yes, SNJ54LS123W is explicitly designed as a retriggerable monostable multivibrator. A new negative-going edge on either A or B input during an active Q output pulse will restart the timing interval from that instant - extending total output width. This behavior is documented in the functional description and timing diagrams of the SDLS043 datasheet and distinguishes SNJ54LS123W from non-retriggerable variants like the SN74121.

What are the recommended external timing components for SNJ54LS123W?

SNJ54LS123W requires external R_EXT and C_EXT components per section to set pulse width. For reliable operation, TI recommends using metal-film resistors (1% tolerance) and NP0/C0G ceramic capacitors (≤10% tolerance). Typical values range from 1 kΩ–100 kΩ for R_EXT and 10 pF–10 µF for C_EXT, yielding pulse widths from ~20 ns to ~20 s. Layout best practice: place R_EXT and C_EXT close to pins 6/7 (Section 1) and 14/15 (Section 2) with short, direct traces.

Is SNJ54LS123W pin-compatible with SN74LS123N?

SNJ54LS123W and SN74LS123N share identical pinout and logic function across all 16 pins, including V_CC (pin 16), GND (pin 8), and dual-section I/O assignments. However, SNJ54LS123W uses CFP packaging with flat leads and SN74LS123N uses PDIP with gull-wing leads - so PCB footprints are not interchangeable. Electrical compatibility is maintained, but mechanical layout must match the specific package type.

What is the reset behavior of SNJ54LS123W?

SNJ54LS123W features an active-low asynchronous RESET input (pin 3 for Section 1, pin 11 for Section 2). When RESET is pulled LOW, Q is forced LOW and Q̅ is forced HIGH immediately - overriding any ongoing timing cycle. Release of RESET returns the section to normal operation, awaiting next valid trigger. This hard reset capability is essential for fail-safe initialization in safety-critical timing paths and is electrically specified in the "DC Characteristics" table of SDLS043.

SNJ54LS123W Specifications

Product attributes: Attribute value

Manufacturer:: Texas Instruments

Series:: 54LS

Package/Case:: 16-CFlatPack

Packaging:: Tube

Product Status:: Active

Logic Type:: Monostable

Independent Circuits:: 2

Schmitt Trigger Input:: No

Propagation Delay:: 34 ns

Current - Output High, Low:: 4mA, 400µA

Voltage - Supply:: 4.5 V ~ 5.5 V

Operating Temperature:: -55°C ~ 125°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 16-CFP

SNJ54LS123W FAQ

1.How can I place an order for SNJ54LS123W through Aetrix?

Please submit a Request for Quotation (RFQ) for SNJ54LS123W 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 SNJ54LS123W reliable?

The price and inventory of SNJ54LS123W are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SNJ54LS123W is usually 5 days.

3.What payment methods are accepted for SNJ54LS123W?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SNJ54LS123W transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SNJ54LS123W?

SNJ54LS123W orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SNJ54LS123W 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 SNJ54LS123W?

For technical support, including SNJ54LS123W datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SNJ54LS123W requirements.

6.How does Aetrix verify that SNJ54LS123W is sourced from the original manufacturer or authorized distributors?

All SNJ54LS123W 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 SNJ54LS123W meets industry standards.

7.What is the process for return or replacement of SNJ54LS123W?

All SNJ54LS123W units undergo pre-shipment inspection (PSI). If there is an issue with SNJ54LS123W, 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 SNJ54LS123W part is unused and in its original packaging.

Return procedure for SNJ54LS123W:

1.Submit a request within 90 days.

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

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