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Texas Instruments SNJ54LS240FK
- Part No.:
- SNJ54LS240FK
- Manufacturer:
- Texas Instruments
- Package:
- 20-CLCC
- Datasheet:
-
SNJ54LS240FK.pdf
- Description:
- 54LS240 OCTAL BUFFERS AND LINE D
- Quantity:
- Payment:
- Shipping:
Inventory:133
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Product details
Overview
SNJ54LS240FK from Texas Instruments is a military-grade octal inverting buffer/line driver with 3-state outputs, designed for memory address and bus driving in high-reliability systems. It features dual 4-bit channels, active-low output-enable (1G and 2G), 15 ns maximum propagation delay at 5 V, ±12 mA output drive, and operates across –55°C to 125°C. It is used in aerospace telemetry interfaces requiring robust signal integrity and bus isolation.
For engineers reviewing the SNJ54LS240FK datasheet, SNJ54LS240FK pinout, SNJ54LS240FK application, or SNJ54LS240FK equivalent, key selection criteria include its LCCC-20 package compatibility with hermetic sealing, MIL-PRF-38535 compliance, 3-state bus contention control, and verified operation under extended temperature extremes.
Technical Context
The SNJ54LS240FK implements two independent 4-bit inverting buffer sections, each with dedicated active-low output-enable inputs (1G and 2G). Its PNP input structure reduces DC loading on upstream logic, while built-in input hysteresis provides 400 mV noise margin-critical for noisy avionics environments.
All outputs are 3-state capable and fully compatible with TTL-level signaling. The device supports bidirectional bus buffering when paired with complementary drivers, and its logic diagram confirms strict inverting behavior: low input yields high output and vice versa, with high-impedance state asserted when either G input is high.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Function | Octal inverting buffer with dual 4-bit channels and independent active-low 3-state enables |
| Propagation Delay | Max 15 ns at VCC = 5 V - ensures timing closure in 33 MHz address/data bus applications |
| Output Drive | ±12 mA (IOL/IOH) - sufficient to drive terminated lines down to 133 Ω without external buffers |
| Operating Temperature | –55°C to +125°C - qualified per MIL-PRF-38535 for space and defense platforms |
| Input Hysteresis | 0.2–0.4 V (VT+ − VT−) - improves noise immunity on long PCB traces or backplanes |
| Supply Voltage | 4.5 V to 5.5 V - compatible with regulated 5-V military power domains |
| Package Type | LCCC-20 (FK) - hermetically sealed ceramic package with 8.89 mm × 8.89 mm footprint |
Pinout & Package
LCCC-20 (FK) package: 20-terminal leadless ceramic chip carrier with gold-plated terminations, designed for surface-mount soldering into high-reliability, thermally stable assemblies. Hermetic seal meets MIL-STD-883 requirements.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | 1G | Active-low output-enable for Channel 1 (A1–A4 → Y1–Y4 inversion) |
| 2 | 1A1 | Inverting input for first bit of Channel 1 |
| 3 | 2Y4 | Inverting output for fourth bit of Channel 2 |
| 4 | 1A2 | Inverting input for second bit of Channel 1 |
| 5 | 2Y3 | Inverting output for third bit of Channel 2 |
| 6 | 1A3 | Inverting input for third bit of Channel 1 |
| 7 | 2Y2 | Inverting output for second bit of Channel 2 |
| 8 | 1A4 | Inverting input for fourth bit of Channel 1 |
| 9 | 2Y1 | Inverting output for first bit of Channel 2 |
| 10 | GND | Signal ground reference for all logic and output stages |
| 11 | 2A1 | Inverting input for first bit of Channel 2 |
| 12 | 1Y4 | Inverting output for fourth bit of Channel 1 |
| 13 | 2A2 | Inverting input for second bit of Channel 2 |
| 14 | 1Y3 | Inverting output for third bit of Channel 1 |
| 15 | 2A3 | Inverting input for third bit of Channel 2 |
| 16 | 1Y2 | Inverting output for second bit of Channel 1 |
| 17 | 2A4 | Inverting input for fourth bit of Channel 2 |
| 18 | 1Y1 | Inverting output for first bit of Channel 1 |
| 19 | 2G/2G | Active-low output-enable for Channel 2 (A1–A4 → Y1–Y4 inversion) |
| 20 | VCC | +5 V supply input - must be decoupled locally with 0.1 µF ceramic capacitor |
Key Features
| Feature | Design Value |
|---|---|
| PNP input structure | Reduces DC loading on upstream TTL or LS logic, minimizing fan-out constraints on address generators |
| Input hysteresis | 400 mV noise margin prevents false triggering on slow-rising or noisy bus signals in EMI-prone environments |
| 3-state output control | Independent 1G/2G enables allow selective channel isolation - essential for time-multiplexed bus arbitration |
| MIL-PRF-38535 compliance | Full screening including burn-in, temperature cycling, and parametric testing for Class B or S devices |
| TTL-compatible I/O | Direct interface with legacy 5-V TTL, LS, and ALS logic families without level-shifting circuitry |
Applications
| Aerospace Telemetry Interface | Defense System Address Bus |
|---|---|
Use Scenario: Buffering and isolating memory-mapped I/O registers in satellite command & data handling (C&DH) subsystems. IC Role / Device Role / Timing Role: Inverting 3-state buffer for bidirectional address/data multiplexing on radiation-hardened backplane buses. Use Value: Enables deterministic bus turnaround via independent G controls, reducing timing uncertainty in fault-tolerant flight software cycles. |
Use Scenario: Driving long-line memory address buses in tactical vehicle computing modules operating under shock/vibration. IC Role / Device Role / Timing Role: High-drive octal buffer ensuring signal integrity across 15 cm PCB traces with >100 pF load capacitance. Use Value: 12 mA sink/source capability maintains VOL ≤0.4 V and VOH ≥2.4 V even under worst-case trace impedance mismatch. |
| Radar Signal Processing Backplane | Secure Communications Crypto Module |
Use Scenario: Re-timing and restoring TTL-level control signals between FPGA-based beamformer and analog front-end ASICs. IC Role / Device Role / Timing Role: Level-restoring repeater with hysteresis to suppress ground bounce-induced glitches on multi-drop control lines. Use Value: Input hysteresis and 15 ns tpd ensure clean setup/hold margins for synchronous sampling at 25 MHz clock rates. |
Use Scenario: Isolating cryptographic key register access paths in TEMPEST-compliant secure processors. IC Role / Device Role / Timing Role: Tamper-evident bus gate using 3-state disable during key-load sequences to prevent side-channel leakage. Use Value: Hermetic LCCC-20 package and MIL-qualified process prevent physical probing of active bus states during secure boot. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal inverting buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SNJ54LS241FK | Non-inverting outputs per channel; identical pinout, timing, and packaging | Used where signal polarity preservation is required (e.g., direct ROM address latching) | Select SNJ54LS241FK only when inverting logic would require additional gates or complicate timing analysis |
| SNJ54S240FK | Faster 7 ns max tpd (vs. 15 ns), higher ICC (100–145 mA), Schottky-clamped outputs | Suitable for high-speed bus repeaters but requires tighter thermal management and stricter layout control | Choose SNJ54S240FK only when propagation delay dominates system timing budget and thermal derating is feasible |
Compared with SNJ54LS240FK, SNJ54LS241FK preserves input polarity for direct address routing, while SNJ54S240FK trades higher power and thermal sensitivity for near-doubling of speed-making SNJ54LS240FK optimal for thermally constrained, noise-immune military control planes.
Availability
SNJ54LS240FK is available at Aetrix Electronics and suitable for aerospace telemetry interfaces, defense system address buses, radar signal processing backplanes, and secure communications crypto modules requiring stable component supply across extended lifecycle programs.
Supply support for SNJ54LS240FK 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 specializing in analog, embedded processing, and high-reliability logic solutions for industrial, automotive, and defense markets.
The SNJ54LS240FK belongs to TI's military logic family designed for ruggedized digital interfacing in mission-critical systems where extended temperature operation, hermetic packaging, and MIL-PRF-38535 qualification are mandatory.
FAQ
What is the operating temperature range for SNJ54LS240FK?
The SNJ54LS240FK is rated for operation from –55°C to +125°C and is fully qualified per MIL-PRF-38535 for high-reliability applications. This range is validated through temperature cycling, steady-state life testing, and parametric verification at both extremes - confirming stable 3-state behavior and propagation delay consistency across the full span. SNJ54LS240FK maintains specified VOH/VOL and tpd performance without derating.
Does SNJ54LS240FK support mixed-voltage interfacing?
Yes, SNJ54LS240FK accepts input voltages down to 2 V and is compatible with both 3.3-V and 5-V logic families. Its PNP input structure and hysteresis enable reliable recognition of lower-voltage signals without level shifters - critical in hybrid systems where FPGAs or microcontrollers operate at 3.3 V while legacy buses remain at 5 V. SNJ54LS240FK does not translate output voltage levels; outputs swing rail-to-rail within the 5-V supply domain.
How is bus contention prevented when using SNJ54LS240FK?
Bus contention is prevented by controlling the 1G and 2G enable inputs to ensure only one SNJ54LS240FK (or other driver) drives the bus at any time. When either G input is high, its associated four outputs enter high-impedance state - electrically disconnecting them from the bus. Proper sequencing of G signals, often synchronized with clock edges or control strobes, guarantees exclusive bus ownership. SNJ54LS240FK's 3-state architecture makes it inherently safe for shared-bus topologies when enabled correctly.
What package type does SNJ54LS240FK use, and why is it significant?
SNJ54LS240FK uses the LCCC-20 (FK) package: a 20-terminal leadless ceramic chip carrier with gold-plated terminations and hermetic ceramic body. This package provides superior thermal stability, moisture resistance, and mechanical robustness - essential for aerospace and defense deployments subject to thermal shock, vibration, and long-term storage. Its low-inductance construction also minimizes switching noise in high-speed digital interfaces, directly supporting SNJ54LS240FK's 15 ns timing specification.
Can SNJ54LS240FK be used as a level restorer in noisy environments?
Yes, SNJ54LS240FK functions effectively as a level restorer due to its built-in 0.2–0.4 V input hysteresis and strong 12 mA output drive. In noisy environments - such as radar backplanes or motor-control cabinets - this hysteresis rejects sub-threshold noise spikes that could cause metastability in downstream logic. Combined with fast edge rates and controlled 3-state transitions, SNJ54LS240FK restores clean TTL waveforms even after signal degradation over long traces or unterminated stubs.
SNJ54LS240FK Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 54LS
- Package/Case:
- 20-CLCC
- Packaging:
- Bulk
- Product Status:
- Active
- Logic Type:
- Buffer, Inverting
- Number of Elements:
- 2
- Number of Bits per Element:
- 4
- Input Type:
- -
- Output Type:
- 3-State
- Current - Output High, Low:
- 12mA, 12mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -55°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-LCCC (8.89x8.89)
SNJ54LS240FK FAQ
1.How can I place an order for SNJ54LS240FK through Aetrix?
Please submit a Request for Quotation (RFQ) for SNJ54LS240FK 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 SNJ54LS240FK reliable?
The price and inventory of SNJ54LS240FK are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SNJ54LS240FK is usually 5 days.
3.What payment methods are accepted for SNJ54LS240FK?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SNJ54LS240FK transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SNJ54LS240FK?
SNJ54LS240FK orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SNJ54LS240FK 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 SNJ54LS240FK?
For technical support, including SNJ54LS240FK datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SNJ54LS240FK requirements.
6.How does Aetrix verify that SNJ54LS240FK is sourced from the original manufacturer or authorized distributors?
All SNJ54LS240FK 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 SNJ54LS240FK meets industry standards.
7.What is the process for return or replacement of SNJ54LS240FK?
All SNJ54LS240FK units undergo pre-shipment inspection (PSI). If there is an issue with SNJ54LS240FK, 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 SNJ54LS240FK part is unused and in its original packaging.
Return procedure for SNJ54LS240FK:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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