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Texas Instruments SNJ54HCT240J
- Part No.:
- SNJ54HCT240J
- Manufacturer:
- Texas Instruments
- Package:
- 20-CDIP (0.300", 7.62mm)
- Datasheet:
-
SNJ54HCT240J.pdf
- Description:
- 54HCT240 OCTAL BUFFERS AND LINE
- Quantity:
- Payment:
- Shipping:
Inventory:106
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Product details
Overview
SNJ54HCT240 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 operating from −55°C to +125°C. It features dual 4-bit channels, TTL-compatible inputs, ±6 mA output drive at 5 V, 12 ns typical propagation delay, and low 80 μA max ICC.
For engineers reviewing the SNJ54HCT240 datasheet, SNJ54HCT240 pinout, SNJ54HCT240 application, or SNJ54HCT240 equivalent, this device serves as a high-current, radiation-tolerant interface solution for aerospace avionics, defense computing, and ruggedized industrial control where wide temperature operation and bus contention management are critical.
Technical Context
The SNJ54HCT240 implements two independent 4-bit inverting buffers, each controlled by its own active-low output-enable (OE) input. Its logic function is strictly inverting: when OE is low, Y = NOT(A); when OE is high, all Y outputs enter high-impedance state - enabling bidirectional bus sharing without external isolation.
It operates exclusively within the 4.5 V–5.5 V supply range and uses HCMOS-compatible input thresholds (VIH = 2.0 V min, VIL = 0.8 V max) while delivering TTL-voltage-compatible outputs. The device meets MIL-PRF-38535 Class B requirements and is qualified for use in safety-critical military platforms.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - ensures compatibility with legacy 5 V TTL and military power rails. |
| Propagation Delay (tpd) | 12 ns typical at 5.5 V, CL = 50 pF - enables reliable timing in high-speed address/data bus applications up to ~40 MHz. |
| Output Drive | ±6 mA at 5 V - directly drives 15 LSTTL loads without external buffering. |
| Input Current | ±1 μA max - minimizes loading on upstream logic and supports high-fanout designs. |
| Quiescent Current (ICC) | 80 μA max - reduces static power in always-on subsystems such as watchdog or boot logic. |
| Operating Temperature | −55°C to +125°C - certified for extended-range deployment in airborne, space, and ground vehicle environments. |
| Logic Function | Inverting 3-state buffer - provides bus arbitration capability via independent OE control per 4-bit group. |
Pinout & Package
SNJ54HCT240 is packaged in a 20-pin Ceramic Dual In-line Package (CDIP, J package), measuring 24.2 mm × 7.62 mm body size with 24.2 mm × 6.92 mm footprint. The package is hermetically sealed, leaded, and SNPB (tin-lead) finished for military solderability and reliability.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | 1OE, 2OE | Active-low output enable inputs - independently disable Channel 1 (pins 2–9) or Channel 2 (pins 11–18). |
| 2, 4, 6, 8 | 1A1–1A4 | Inverting input pins for Channel 1 - drive corresponding Y outputs when OE is low. |
| 3, 5, 7, 9 | 1Y2–1Y4, 1Y1 | Inverting output pins for Channel 1 - high-impedance when 1OE = high. |
| 11, 13, 15, 17 | 2A1–2A4 | Inverting input pins for Channel 2 - electrically isolated from Channel 1 except via shared VCC/GND. |
| 12, 14, 16, 18 | 1Y4–1Y2, 1Y1 (reordered), 2Y1–2Y4 | Inverting output pins for Channel 2 - pin 12 = 1Y4, pin 14 = 1Y3, pin 16 = 1Y2, pin 18 = 1Y1; pin 3 = 2Y4, etc. |
| 10, 20 | GND, VCC | Ground and 5 V power supply pins - require local 0.1 μF bypass capacitor per datasheet recommendation. |
Key Features
| Feature | Design Value |
|---|---|
| TTL-compatible inputs | VIH = 2.0 V min, VIL = 0.8 V max - interoperates directly with legacy TTL, LS-TTL, and 5 V CMOS logic families. |
| High-output current drive | ±6 mA per output - eliminates need for discrete transistor buffers in memory address latching circuits. |
| Low quiescent power | 80 μA max ICC - extends battery life in standby modes of portable military radios and telemetry units. |
| 3-state bus interface | Dual independent OE controls - allows time-multiplexed sharing of a single data/address bus between multiple subsystems. |
| Military temperature range | −55°C to +125°C operation - validated for use in jet engine controllers, missile guidance electronics, and satellite payload interfaces. |
Applications
| Avionics Data Bus Interface | Secure Boot ROM Address Buffer |
|---|---|
Use Scenario: Interfacing microprocessor address lines to multiple memory banks in a flight control computer. IC Role / Device Role / Timing Role: Inverting 3-state buffer isolating CPU address bus from shared RAM/ROM address decoders. Use Value: Enables dynamic bus arbitration during DMA transfers while maintaining signal integrity across −55°C to +125°C thermal cycling. |
Use Scenario: Driving boot ROM address lines in a radiation-hardened FPGA configuration controller. IC Role / Device Role / Timing Role: Octal inverting buffer ensuring clean, slew-controlled address transitions during cold-start initialization. Use Value: Guarantees setup/hold timing margins under worst-case voltage and temperature extremes per MIL-STD-883. |
| Ruggedized Industrial PLC Backplane | Tactical Radio Baseband Signal Routing |
Use Scenario: Isolating I/O module address decoding logic from main CPU backplane in oilfield drilling controllers. IC Role / Device Role / Timing Role: Dual-channel 3-state buffer managing contention between master CPU and slave I/O processors. Use Value: Prevents bus contention faults during hot-swap events and maintains ESD immunity per MIL-STD-461G CS114. |
Use Scenario: Routing baseband I/Q address and control signals between DSP and RF transceiver ASICs in handheld radios. IC Role / Device Role / Timing Role: Low-skew inverting buffer synchronizing memory-mapped register access across mixed-signal domains. Use Value: Delivers sub-15 ns propagation delay consistency across full military temperature range, minimizing phase jitter in digital upconversion paths. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal inverting 3-state buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN54HCT240J | Same CDIP-20 package, identical electrical specs, but rated for −55°C to +125°C without QML-38535 certification. | Acceptable for non-certified military programs where full QML qualification is not mandated. | Select SN54HCT240J only if formal QML documentation and lot traceability are not required. |
| SN74HCT240N | Commercial-grade PDIP-20 variant; rated −40°C to +85°C, RoHS-compliant, NIPDAU finish. | Suitable for industrial prototypes or non-ruggedized embedded systems where cost and availability outweigh environmental demands. | Choose SN74HCT240N for lab validation or commercial derivatives - not for flight hardware or deployed field systems. |
Compared with SN54HCT240J and SN74HCT240N, the SNJ54HCT240 offers full QML-38535 Class B qualification, guaranteed lot traceability, and extended screening - making it the sole option for production-critical avionics and defense electronics requiring documented reliability and radiation tolerance.
Availability
SNJ54HCT240 is available at Aetrix Electronics and suitable for avionics data bus interface, secure boot ROM address buffering, ruggedized industrial PLC backplane, and tactical radio baseband signal routing requiring stable component supply across extended temperature ranges and long lifecycle commitments.
Supply support for SNJ54HCT240 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 specializing in analog, embedded processing, and high-reliability components for aerospace, defense, and industrial markets.
The SNJ54HCT240 belongs to TI's military logic family, engineered specifically for high-density, high-current 3-state bus driving in safety-critical systems where performance, temperature resilience, and qualification rigor are non-negotiable.
FAQ
What is the operating temperature range of the SNJ54HCT240?
The SNJ54HCT240 is specified for continuous operation from −55°C to +125°C. This extended range is verified per MIL-PRF-38535 and supports deployment in jet engines, satellite payloads, and armored vehicle electronics where ambient conditions exceed commercial limits. The SNJ54HCT240 maintains full electrical compliance across this entire span without derating.
Does the SNJ54HCT240 support non-inverting logic functions?
No, the SNJ54HCT240 implements only inverting logic: Y = NOT(A) when OE is active low. It does not provide true non-inverting functionality. For non-inverting 3-state buffering, engineers must select alternatives such as SNJ54HCT244 or pair SNJ54HCT240 with external inverters - though doing so increases propagation delay and board area.
What is the maximum capacitive load the SNJ54HCT240 can drive reliably?
The SNJ54HCT240 is characterized for CL = 50 pF and CL = 150 pF loads in its switching specifications. At 5.5 V supply and 25°C, tpd remains within 56 ns (max) even at 150 pF. For loads exceeding 150 pF, signal integrity degrades due to increased rise/fall times; external series termination or buffer staging is recommended for >200 pF applications.
Is the SNJ54HCT240 pin-compatible with SN74HCT240 variants?
Yes, the SNJ54HCT240 shares identical pinout and logic function with all SN74HCT240 packages (DGS, DW, N, NS, PW), including the CDIP-20 layout. However, mechanical dimensions, thermal characteristics, and qualification level differ - SNJ54HCT240 uses ceramic hermetic sealing and MIL-spec screening, whereas SN74HCT240N uses plastic DIP with commercial reliability testing.
What packaging and marking information identifies an authentic SNJ54HCT240?
An authentic SNJ54HCT240 carries the part marking "SNJ54HCT240J" laser-etched on the top surface of its 20-pin CDIP package, along with a TI logo and lot trace code. It ships in anti-static tubes labeled "8550501RA" or "SNJ54HCT240J", with SNPB (tin-lead) leads and no RoHS exemption markings - distinguishing it from RoHS-compliant commercial variants.
SNJ54HCT240J Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 54HCT
- Package/Case:
- 20-CDIP (0.300", 7.62mm)
- 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:
- 6mA, 6mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -55°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 20-CDIP
SNJ54HCT240J FAQ
1.How can I place an order for SNJ54HCT240J through Aetrix?
Please submit a Request for Quotation (RFQ) for SNJ54HCT240J 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 SNJ54HCT240J reliable?
The price and inventory of SNJ54HCT240J are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SNJ54HCT240J is usually 5 days.
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Once your SNJ54HCT240J 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 SNJ54HCT240J?
For technical support, including SNJ54HCT240J datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SNJ54HCT240J requirements.
6.How does Aetrix verify that SNJ54HCT240J is sourced from the original manufacturer or authorized distributors?
All SNJ54HCT240J 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 SNJ54HCT240J meets industry standards.
7.What is the process for return or replacement of SNJ54HCT240J?
All SNJ54HCT240J units undergo pre-shipment inspection (PSI). If there is an issue with SNJ54HCT240J, 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 SNJ54HCT240J part is unused and in its original packaging.
Return procedure for SNJ54HCT240J:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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