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Home > Products > Integrated Circuits (ICs) > Logic > Buffers, Drivers, Receivers, Transceivers

Texas Instruments SN54HCT240J

Name: SN54HCT240J
Brand: Texas Instruments
SKU: SN54HCT240J
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SN54HCT240J

Manufacturer:: Texas Instruments

Category:: Buffers, Drivers, Receivers, Transceivers

Package:: 20-CDIP (0.300", 7.62mm)

Datasheet:: SN54HCT240J.pdf

Description:: 54HCT240 OCTAL BUFFERS AND LINE

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Product details

Overview

SN54HCT240J from Texas Instruments is a military-grade octal inverting 3-state buffer/driver IC designed for memory address and bus driving in high-reliability systems. It operates from 4.5 V to 5.5 V, delivers ±6-mA output drive at 5 V, features typical propagation delay of 12 ns, and supports −55°C to +125°C operation in CDIP-J package.

For engineers reviewing the SN54HCT240J datasheet, SN54HCT240J pinout, SN54HCT240J application, or SN54HCT240J equivalent, key selection criteria include its TTL-compatible inputs, high-current 3-state outputs, low ICC (80 µA max), and qualification per MIL-PRF-38535 Class B for aerospace and defense platforms.

Technical Context

The SN54HCT240J implements two independent 4-bit inverting buffers, each with dedicated active-low output-enable (OE) control. Its logic function is strictly inverting: when OE is low, Y = NOT(A); when OE is high, outputs enter high-impedance state.

It uses HCMOS technology with TTL-voltage-level input thresholds (VIH = 2 V min, VIL = 0.8 V max), enabling direct interface with legacy TTL logic. The device meets military temperature and reliability requirements, including storage range of −65°C to +150°C and absolute maximum supply voltage of −0.5 V to 7 V.

Key Specifications

Parameter	Value and Actual Design Meaning
Supply Voltage Range	4.5 V to 5.5 V - Ensures compatibility with standard 5-V TTL and CMOS systems without level-shifting.
Propagation Delay (tpd)	12 ns typ @ 5.5 V, CL = 50 pF - Enables reliable operation in high-speed address/data bus timing paths up to ~40 MHz.
Output Drive Capability	±6 mA @ 5 V - Sufficient to drive 15 LSTTL loads directly, eliminating need for external bus transceivers in many designs.
Quiescent Supply Current (ICC)	80 µA max - Minimizes standby power in battery-backed or thermally constrained military subsystems.
Input Voltage Compatibility	TTL-level (VIH ≥ 2 V, VIL ≤ 0.8 V) - Allows seamless integration with legacy 74LS/74S logic families without interface circuitry.
Operating Temperature Range	−55°C to +125°C - Qualified for deployment in extended-environment avionics, missile guidance, and space-qualified electronics.
3-State Enable Time (ten)	19 ns max @ 5.5 V - Supports fast bus arbitration and dynamic resource sharing in multiprocessor or shared-memory architectures.

Pinout & Package

SN54HCT240J is housed in a 20-pin Ceramic Dual In-line Package (CDIP-J) with 0.3-inch body width, through-hole mounting, and hermetic ceramic-glass seal for moisture resistance and long-term reliability in harsh environments.

Pin/Terminal	Circuit Role	Design Meaning
1OE, 2OE	Active-Low Output Enable	Independent controls for Group 1 (pins 1A1–1A4 → 1Y1–1Y4) and Group 2 (2A1–2A4 → 2Y1–2Y4); both must be low for output assertion.
1A1–1A4, 2A1–2A4	Input Data Lines	Eight buffered inputs; each inverted and gated by its group's OE before reaching corresponding Y output.
1Y1–1Y4, 2Y1–2Y4	Inverted 3-State Outputs	Eight high-drive, TTL-compatible outputs; tri-stated when respective OE is high, enabling bus contention avoidance.
VCC (Pin 20)	Positive Supply	5-V nominal supply connection; decoupling capacitor placement near this pin is critical for noise immunity in high-speed switching.
GND (Pin 10)	Ground Reference	Common return path for all signals and supply current; requires low-inductance connection to minimize ground bounce.

Key Features

Feature	Design Value
MIL-PRF-38535 Class B Qualification	Meets rigorous screening, testing, and traceability requirements for defense-critical applications including burn-in, temperature cycling, and lot acceptance tests.
High-Current 3-State Outputs	±6-mA drive capability enables direct interfacing with multiple LSTTL loads while maintaining signal integrity during bus contention scenarios.
TTL-Compatible Input Thresholds	VIH = 2 V min / VIL = 0.8 V max ensures robust noise margin and interoperability with legacy 74LS, 74S, and 74F logic families without level translation.
Low Quiescent Power	80 µA max ICC allows use in always-on subsystems where thermal management and battery life are design constraints.
Hermetic CDIP-J Package	Ceramic DIP construction provides superior moisture resistance, thermal stability, and long-term reliability under extreme temperature and humidity conditions.

Applications

Avionics Data Bus Interface	Missile Guidance Memory Buffering
Use Scenario: Isolating and driving address lines between flight computer CPU and radiation-hardened SRAM modules in airborne mission computers. IC Role / Device Role / Timing Role: Octal inverting buffer providing level-shifted, high-drive, 3-state-controlled memory address latching with precise timing alignment. Use Value: Enables deterministic bus turnaround and eliminates address skew across eight parallel lines under −55°C to +125°C thermal cycling.	Use Scenario: Controlling bidirectional data flow between inertial measurement unit (IMU) processor and nonvolatile configuration EEPROM in guided munitions. IC Role / Device Role / Timing Role: Bidirectional bus driver with independent OE control for time-multiplexed read/write cycles in safety-critical firmware update paths. Use Value: Guarantees glitch-free bus release via fast 19-ns enable/disable times, preventing corruption during power-up/power-down transitions.
Satellite Onboard Computer I/O Expansion	Ground-Based Radar Signal Processing Backplane
Use Scenario: Expanding GPIO capacity of radiation-tolerant FPGA by buffering control signals to telemetry modulators and antenna pointing actuators. IC Role / Device Role / Timing Role: Inverting 3-state driver translating FPGA logic levels to robust 5-V bus signals with ESD-hardened inputs. Use Value: Delivers 12-ns propagation delay consistency across full temperature range, ensuring deterministic timing closure in orbital thermal vacuum environments.	Use Scenario: Driving high-fanout clock and trigger distribution networks across multi-board radar receiver assemblies operating in desert field conditions. IC Role / Device Role / Timing Role: Low-skew, high-drive buffer isolating master timing controller from distributed ADC/DAC timing inputs. Use Value: ±6-mA output drive sustains signal integrity over 15 cm backplane traces while maintaining <1 ns inter-output skew at 5 V.

Avionics Data Bus Interface

Missile Guidance Memory Buffering

Use Scenario: Isolating and driving address lines between flight computer CPU and radiation-hardened SRAM modules in airborne mission computers.

IC Role / Device Role / Timing Role: Octal inverting buffer providing level-shifted, high-drive, 3-state-controlled memory address latching with precise timing alignment.

Use Value: Enables deterministic bus turnaround and eliminates address skew across eight parallel lines under −55°C to +125°C thermal cycling.

Use Scenario: Controlling bidirectional data flow between inertial measurement unit (IMU) processor and nonvolatile configuration EEPROM in guided munitions.

IC Role / Device Role / Timing Role: Bidirectional bus driver with independent OE control for time-multiplexed read/write cycles in safety-critical firmware update paths.

Use Value: Guarantees glitch-free bus release via fast 19-ns enable/disable times, preventing corruption during power-up/power-down transitions.

Satellite Onboard Computer I/O Expansion

Ground-Based Radar Signal Processing Backplane

Use Scenario: Expanding GPIO capacity of radiation-tolerant FPGA by buffering control signals to telemetry modulators and antenna pointing actuators.

IC Role / Device Role / Timing Role: Inverting 3-state driver translating FPGA logic levels to robust 5-V bus signals with ESD-hardened inputs.

Use Value: Delivers 12-ns propagation delay consistency across full temperature range, ensuring deterministic timing closure in orbital thermal vacuum environments.

Use Scenario: Driving high-fanout clock and trigger distribution networks across multi-board radar receiver assemblies operating in desert field conditions.

IC Role / Device Role / Timing Role: Low-skew, high-drive buffer isolating master timing controller from distributed ADC/DAC timing inputs.

Use Value: ±6-mA output drive sustains signal integrity over 15 cm backplane traces while maintaining <1 ns inter-output skew at 5 V.

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
SNJ54HCT240J	Identical electrical specs and CDIP-J packaging; differs only in TI's internal part numbering convention and screening documentation format.	No functional or application difference; both qualified to same MIL-PRF-38535 Class B requirements.	Select SN54HCT240J for standard military procurement channels; SNJ54HCT240J may appear in legacy DoD BOMs or specific contract line items.
SN74HCT240N	Commercial-grade version in PDIP-N package; rated only for −40°C to +85°C and lacks MIL-PRF-38535 qualification.	Not suitable for aerospace or defense deployments requiring extended temperature or reliability assurance; limited to industrial prototypes or ground-test benches.	Use SN74HCT240N only for cost-sensitive, non-mission-critical development; SN54HCT240J remains mandatory for flight hardware and certified systems.

Compared with SNJ54HCT240J, SN54HCT240J offers identical performance but aligns with current TI military part numbering standards; versus SN74HCT240N, it adds full military qualification, extended temperature support, and hermetic packaging-critical for system-level certification in defense programs.

Availability

SN54HCT240J is available at Aetrix Electronics and suitable for avionics data bus interface, missile guidance memory buffering, satellite onboard computer I/O expansion, and ground-based radar signal processing backplane applications requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SN54HCT240J 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, embedded processing, and high-reliability logic solutions for industrial, automotive, and defense markets.

The SN54HCT240J belongs to TI's military logic family, engineered specifically to meet MIL-PRF-38535 Class B requirements for aerospace and defense systems demanding guaranteed performance across −55°C to +125°C and lifetime reliability under shock, vibration, and radiation exposure.

FAQ

What is the operating temperature range of the SN54HCT240J?

The SN54HCT240J is specified for operation from −55°C to +125°C, meeting MIL-PRF-38535 Class B environmental requirements. This extended range supports deployment in jet engine bays, missile seeker housings, and satellite payload compartments where ambient temperatures exceed commercial-grade limits. The SN54HCT240J maintains full electrical compliance-including propagation delay, output drive, and input thresholds-across this entire span without derating.

Does the SN54HCT240J require external pull-up or pull-down resistors on unused inputs?

Yes, all unused inputs of the SN54HCT240J must be tied to either VCC or GND to prevent floating nodes that could cause excessive ICC, logic instability, or increased EMI susceptibility. TI's application report SCBA004 explicitly mandates this practice for HCT devices. Leaving inputs unconnected violates the recommended operating conditions and risks unpredictable behavior, especially under temperature extremes where leakage currents increase.

How does the SN54HCT240J differ from the commercial SN74HCT240 series?

The SN54HCT240J differs from SN74HCT240 variants in three key ways: it is screened and tested to MIL-PRF-38535 Class B standards, rated for −55°C to +125°C operation (vs. −40°C to +85°C), and packaged in hermetic CDIP-J instead of plastic SOIC or TSSOP. These differences make SN54HCT240J suitable for flight-critical systems, whereas SN74HCT240 is intended for commercial or industrial prototyping only.

What is the maximum capacitive load the SN54HCT240J can drive reliably?

The SN54HCT240J is characterized for CL = 50 pF and CL = 150 pF loads, with propagation delay increasing from 12 ns to 19 ns (typ) at 5.5 V. While not explicitly rated beyond 150 pF, its ±6-mA output drive supports stable edge rates into >200 pF when combined with proper PCB layout-such as controlled-impedance traces and local decoupling. Exceeding 150 pF requires validation of setup/hold margins in the target system.

Is the SN54HCT240J pin-compatible with other members of the '240 family?

Yes, the SN54HCT240J shares identical pinout and logic function with all '240-series devices, including SN74HCT240N, SN74HCT240DW, and SNJ54HCT240J. All use the same 20-pin topology with matching 1OE/2OE, A-input, Y-output, VCC, and GND assignments. However, mechanical compatibility depends on package type: CDIP-J requires through-hole mounting, unlike surface-mount SOIC or TSSOP variants.

SN54HCT240J 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

SN54HCT240J FAQ

1.How can I place an order for SN54HCT240J through Aetrix?

Please submit a Request for Quotation (RFQ) for SN54HCT240J 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 SN54HCT240J reliable?

The price and inventory of SN54HCT240J are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN54HCT240J is usually 5 days.

3.What payment methods are accepted for SN54HCT240J?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN54HCT240J transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SN54HCT240J?

SN54HCT240J orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SN54HCT240J 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 SN54HCT240J?

For technical support, including SN54HCT240J datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN54HCT240J requirements.

6.How does Aetrix verify that SN54HCT240J is sourced from the original manufacturer or authorized distributors?

All SN54HCT240J 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 SN54HCT240J meets industry standards.

7.What is the process for return or replacement of SN54HCT240J?

All SN54HCT240J units undergo pre-shipment inspection (PSI). If there is an issue with SN54HCT240J, 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 SN54HCT240J part is unused and in its original packaging.

Return procedure for SN54HCT240J:

1.Submit a request within 90 days.

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

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