My Inquiry
My Account
Texas Instruments SNJ54LS123J
- Part No.:
- SNJ54LS123J
- Manufacturer:
- Texas Instruments
- Category:
- Multivibrators
- Package:
- 16-CDIP (0.300", 7.62mm)
- Datasheet:
-
SNJ54LS123J.pdf
- Description:
- RETRIGGERABLE MONOSTABLE MULTIVI
- Quantity:
- Payment:
- Shipping:
Inventory:4,516
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SNJ54LS123J from Texas Instruments is a retriggerable monostable multivibrator in a 16-pin CDIP (J) package, operating over –55°C to +125°C, with TTL-compatible inputs and outputs, dual independent channels, and programmable output pulse width via external RC networks. It serves as a precision timing element in military-grade digital systems requiring noise-immune edge-triggered delay or pulse shaping.
For engineers reviewing the SNJ54LS123J datasheet, SNJ54LS123J pinout, SNJ54LS123J application, or SNJ54LS123J equivalent, this device supports critical timing functions in radar pulse generation, missile guidance interface logic, and avionics reset synchronization where extended temperature range and radiation-tolerant packaging are mandatory.
Technical Context
The SNJ54LS123J implements two independent retriggerable monostable circuits, each with separate A and B trigger inputs, clear (CLR) control, and Q/Q̅ complementary outputs. Its TTL input thresholds (VIH = 2.0 V min, VIL = 0.8 V max) and output drive capability (IOH = –0.4 mA, IOL = 8 mA) ensure robust interfacing with legacy 5-V logic families.
Timing is set externally per channel using a resistor (RA/RB) and capacitor (CA/CB), yielding pulse widths from 30 ns to >10 s; propagation delay is 25 ns typical at VCC = 5 V. The device uses bipolar Schottky-clamped transistor technology for high-speed operation without latch-up risk under normal conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Function | Dual retriggerable monostable multivibrator - enables continuous pulse extension on repeated triggers without resetting the timer |
| Supply Voltage | 4.5 V to 5.5 V - compatible with standard military-grade 5-V power rails and tolerant of supply ripple |
| Operating Temperature | –55°C to +125°C - qualified for extended-range military applications per MIL-PRF-38535 Class V |
| Propagation Delay | 25 ns typical (tPLH/tPHL) - ensures sub-30 ns timing resolution for high-speed digital control loops |
| Output Drive | IOL = 8 mA / IOH = –0.4 mA - directly drives TTL loads or small capacitive buses without buffer stages |
| Input Thresholds | VIL = 0.8 V max / VIH = 2.0 V min - provides 0.4 V noise margin against ground bounce and crosstalk in dense PCB layouts |
| Pulse Width Range | 30 ns to >10 s per channel - configurable via external RA/CA or RB/CB networks for flexible timing granularity |
Pinout & Package
SNJ54LS123J is housed in a hermetically sealed 16-pin Ceramic Dual In-line Package (CDIP, J), with 0.3-inch body width, 0.1-inch lead pitch, and tin-lead (SNPB) finish. The package meets MIL-STD-883 requirements for mechanical shock, vibration, and thermal cycling.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4 | Channel 1 trigger inputs (A1, B1), CLR1, Q1 | A1/B1 accept positive-edge or negative-edge triggers; CLR1 asynchronously resets output low; Q1 is active-high output |
| 5, 6, 7, 8 | Channel 1 timing components (RA1, CA1), GND, Q̅1 | RA1/CA1 set pulse width; GND is dedicated analog/digital reference; Q̅1 provides inverted output |
| 9, 10, 11, 12 | Channel 2 trigger inputs (A2, B2), CLR2, Q2 | Independent second channel with identical retriggerable behavior and asynchronous clear |
| 13, 14, 15, 16 | Channel 2 timing components (RA2, CA2), VCC, Q̅2 | RA2/CA2 configure second pulse width; VCC supplies both channels; Q̅2 complements Q2 |
Key Features
| Feature | Design Value |
|---|---|
| Retriggerable operation | Allows new trigger events to extend the current output pulse - essential for synchronizing variable-rate sensor interrupts |
| Dual independent channels | Eliminates need for two discrete monostables - reduces board area and interconnect complexity in timing-critical subsystems |
| Military temperature range | –55°C to +125°C operation validated per MIL-STD-883 Method 1010 - suitable for airborne and space-qualified platforms |
| TTL-compatible I/O | Direct interface with legacy 74LS/74S logic families without level-shifting - preserves signal integrity in mixed-technology designs |
| External RC timing | Wide pulse width adjustability (30 ns–10 s) using standard resistors/capacitors - avoids fixed-delay ICs requiring redesign for timing changes |
Applications
| Radar Pulse Shaping | Avionics System Reset |
|---|---|
Use Scenario: Conditioning raw RF detector pulses into clean, uniform-width gate signals for time-of-flight measurement. IC Role / Device Role / Timing Role: Monostable channel 1 generates precise 500-ns strobe pulses synchronized to leading edges of incoming radar returns. Use Value: Enables consistent echo sampling window across temperature extremes, improving range resolution by ±0.5 m in airborne SAR systems. |
Use Scenario: Generating a 10-ms system-wide reset pulse upon power-up or watchdog timeout in flight control computers. IC Role / Device Role / Timing Role: Channel 2 delivers a guaranteed-width reset assertion using R = 10 kΩ, C = 1 µF network. Use Value: Ensures deterministic initialization of FPGAs and microcontrollers despite voltage ramp variations across –55°C to +125°C. |
| Missile Guidance Interface | Secure Communication Timing |
Use Scenario: Debouncing and stretching short-duration telemetry interrupt signals before feeding to a radiation-hardened processor. IC Role / Device Role / Timing Role: Channel 1 acts as a hardware-based edge filter with 200-ns minimum pulse width guarantee. Use Value: Prevents spurious CPU interrupts caused by EMI-induced glitches on launch vehicle bus lines. |
Use Scenario: Synchronizing encryption key loading windows between secure crypto modules in tactical radios. IC Role / Device Role / Timing Role: Dual channels generate matched 1-µs enable pulses for parallel AES core activation. Use Value: Eliminates clock skew-induced timing violations during cryptographic key handoff sequences. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar retriggerable monostable multivibrator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SNJ54LS123W | Same electrical specs, but in 16-pin CFP (W) ceramic flatpack package with gull-wing leads | Better thermal dissipation and lower parasitic inductance; preferred for high-vibration environments | Select when board-level shock/vibration exceeds 20 g RMS or when lead coplanarity tolerance < 0.1 mm is required |
| SNJ54LS123FK | Same functionality in 20-pin LCCC (FK) package with no leads and 1.27-mm pitch | Superior high-frequency stability and hermetic sealing; used in space-qualified designs per MIL-PRF-38535 Class Q | Select for radiation-tolerant missions or when surface-mount assembly with zero lead inductance is mandatory |
Compared with SNJ54LS123W and SNJ54LS123FK, the SNJ54LS123J offers lowest-cost through-hole assembly and widest legacy design support, while maintaining full functional equivalence and military temperature qualification - ideal for cost-sensitive defense electronics upgrades.
Availability
SNJ54LS123J is available at Aetrix Electronics and suitable for radar pulse conditioning, avionics reset sequencing, and missile telemetry interface applications requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for SNJ54LS123J 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 U.S.-based semiconductor company founded in 1930, specializing in analog and embedded processing technologies with deep heritage in military and aerospace components.
The SNJ54LS123J belongs to TI's 54LS logic family, designed specifically for high-reliability defense systems requiring extended temperature operation, hermetic packaging, and compliance with MIL-PRF-38535 Class V standards.
FAQ
What is the maximum operating frequency of the SNJ54LS123J?
The SNJ54LS123J does not operate at a fixed clock frequency; instead, it generates single-shot pulses with widths determined by external RC networks. Its minimum pulse width is 30 ns, enabling effective use in systems with timing events up to ~33 MHz repetition rate. The device itself has no internal oscillator - all timing derives from user-selected RA/CA and RB/CB values.
Does the SNJ54LS123J support non-retriggerable mode?
No, the SNJ54LS123J is exclusively a retriggerable monostable multivibrator. It lacks a non-retriggerable configuration option. If a non-retriggerable function is required, an external gating circuit or alternative part such as SN74LS221 must be used. The datasheet confirms retriggerability as a defining feature across all 54LS123 variants.
Can the SNJ54LS123J be used with modern 3.3-V logic systems?
The SNJ54LS123J is specified only for 4.5–5.5 V operation and TTL-level input thresholds. Direct connection to 3.3-V logic risks undervoltage input recognition and potential damage due to input clamp diode conduction. Level translation (e.g., SN74LVC1T45) is required for interoperability with 3.3-V systems.
What is the meaning of "J" in the SNJ54LS123J part number?
The "J" suffix in SNJ54LS123J denotes the Ceramic Dual In-line Package (CDIP) variant per TI's standard packaging nomenclature. This distinguishes it from "W" (CFP), "FK" (LCCC), and commercial "N" (PDIP) versions. The "J" package features through-hole leads, hermetic ceramic construction, and military-grade reliability screening.
Is the SNJ54LS123J RoHS compliant?
No, the SNJ54LS123J uses a tin-lead (SNPB) lead finish and is explicitly marked "RoHS: No" in TI's packaging documentation. It is intended for legacy military/aerospace applications where leaded solder and hermetic packaging are mandated by specification - not for consumer or industrial RoHS-compliant designs.
SNJ54LS123J Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 54LS
- Package/Case:
- 16-CDIP (0.300", 7.62mm)
- 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:
- Through Hole
- Supplier Device Package:
- 16-CDIP
SNJ54LS123J FAQ
1.How can I place an order for SNJ54LS123J through Aetrix?
Please submit a Request for Quotation (RFQ) for SNJ54LS123J 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 SNJ54LS123J reliable?
The price and inventory of SNJ54LS123J are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SNJ54LS123J is usually 5 days.
3.What payment methods are accepted for SNJ54LS123J?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SNJ54LS123J transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SNJ54LS123J?
SNJ54LS123J orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SNJ54LS123J 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 SNJ54LS123J?
For technical support, including SNJ54LS123J datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SNJ54LS123J requirements.
6.How does Aetrix verify that SNJ54LS123J is sourced from the original manufacturer or authorized distributors?
All SNJ54LS123J 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 SNJ54LS123J meets industry standards.
7.What is the process for return or replacement of SNJ54LS123J?
All SNJ54LS123J units undergo pre-shipment inspection (PSI). If there is an issue with SNJ54LS123J, 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 SNJ54LS123J part is unused and in its original packaging.
Return procedure for SNJ54LS123J:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SNJ54LS123J Tags
-
SN74LVC1G123DCUR
Texas Instruments
-
CD4047BM96
Texas Instruments
-
SN74LVC1G123DCTR
Texas Instruments
-
CD74HC221M96
Texas Instruments
-
CD14538BE
Texas Instruments
-
SN74LVC1G123YZPR
Texas Instruments
-
SN74LVC1G123DCUT
Texas Instruments
-
MC14538BDR2G
onsemi
-
74VHC123AMX
onsemi
-
LTC6993CS6-2#TRMPBF
Analog Devices Inc.
-
LTC6993CS6-3#TRMPBF
Analog Devices Inc.
-
LTC6993CS6-1#TRMPBF
Analog Devices Inc.
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
