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Texas Instruments SN74HCT240DWRE4
- Part No.:
- SN74HCT240DWRE4
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74HCT240DWRE4.pdf
- Description:
- IC BUFFER INVERT 5.5V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,381
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Product details
Overview
SN74HCT240DWRE4 from Texas Instruments is an octal inverting buffer/line driver with 3-state outputs, designed for memory address and bus driving in 5V TTL-compatible systems. It operates from 4.5V to 5.5V, delivers ±6mA output drive, exhibits 12ns typical propagation delay at 5.5V, and draws ≤80μA quiescent current. It is used in industrial control backplanes and microcontroller I/O expansion interfaces.
For engineers reviewing the SN74HCT240DWRE4 datasheet, SN74HCT240DWRE4 pinout, SN74HCT240DWRE4 application, or SN74HCT240DWRE4 equivalent, key selection criteria include 3-state bus contention management, TTL-level input compatibility, SOIC-20 package footprint, and guaranteed high-current drive into LSTTL loads without external pull-ups.
Technical Context
The SN74HCT240DWRE4 implements two independent 4-bit inverting buffers, each controlled by a dedicated output-enable (OE) input. When OE is low, inverted data passes from A inputs to Y outputs; when OE is high, all eight outputs enter high-impedance state-enabling bidirectional bus sharing without external logic.
Its HCT logic family ensures CMOS power efficiency with TTL voltage thresholds: VIH = 2.0V min and VIL = 0.8V max across 4.5–5.5V supply, while maintaining 1μA max input leakage and 6mA output sink/source capability at VCC = 5V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5V to 5.5V - compatible with standard 5V logic rails and tolerant of ±5% regulation variation |
| Propagation Delay | 12ns typical at 5.5V - enables reliable operation in 30MHz+ address/data strobe timing windows |
| Output Drive | ±6mA at 5V - directly drives 15 LSTTL loads without buffering or pull-up resistors |
| Input Thresholds | VIH = 2.0V min, VIL = 0.8V max - ensures robust interfacing with legacy TTL and microcontroller GPIO |
| Quiescent Current | ≤80μA max - supports low-power standby modes in battery-backed or energy-sensitive systems |
| 3-State Enable Time | 19ns max (ten) at 5.5V - allows fast bus arbitration and multiplexing in real-time control loops |
| Input Leakage | ±1μA max - prevents unintended logic transitions on unterminated or high-impedance control lines |
Pinout & Package
SN74HCT240DWRE4 uses a 20-pin SOIC (DW) package measuring 12.80mm × 10.3mm with 1.27mm pitch, RoHS-compliant NiPdAu lead finish, and moisture sensitivity level 1 (260°C peak reflow).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | Output Enable (1OE, 2OE) | Active-low enables respective 4-bit buffer group; tied high disables both groups simultaneously |
| 2–4, 6–8, 11–13, 15–17 | Inputs (1A1–1A4, 2A1–2A4) | Inverting data inputs; TTL-compatible thresholds allow direct connection to MCU ports or FPGA I/O |
| 3–5, 7, 9, 12, 14, 16, 18 | Outputs (1Y1–1Y4, 2Y1–2Y4) | Inverted, 3-state outputs; drive buses or memory address latches with no contention during disable |
| 10 | GND | Ground reference for all logic and output stages; requires low-inductance connection to minimize switching noise |
| 20 | VCC | 5V power supply; must be decoupled with ≥0.1μF ceramic capacitor placed adjacent to pin |
Key Features
| Feature | Design Value |
|---|---|
| Inverting 3-state buffers | Two independent 4-bit groups enable selective bus isolation without external gating logic |
| TTL-compatible inputs | VIH/VIL thresholds match legacy 5V TTL, eliminating level-shifter requirements in mixed-logic systems |
| High-output current | ±6mA drive sustains signal integrity across 15 LSTTL loads or long PCB traces up to 15cm |
| Low ICC quiescent draw | ≤80μA operation supports always-on monitoring circuits without compromising system power budget |
| SOIC-20 packaging | Standard 12.8mm × 10.3mm footprint ensures drop-in replacement in existing 5V logic layouts |
Applications
| Memory Address Buffering | Microcontroller I/O Expansion |
|---|---|
Use Scenario: Driving 16-bit address bus for SRAM or EPROM in embedded controllers with limited drive strength. IC Role / Device Role / Timing Role: Inverting 3-state buffer isolating CPU address lines from memory chips during DMA cycles. Use Value: Eliminates need for discrete transistors or additional logic gates while ensuring clean edge transitions at 30MHz clock rates. | Use Scenario: Expanding GPIO count of an 8-bit MCU to interface with multiple peripherals via shared data bus. IC Role / Device Role / Timing Role: Bidirectional bus driver enabling time-multiplexed access to ADC, DAC, and display controller. Use Value: Enables hardware-controlled bus arbitration with sub-20ns enable/disable timing, reducing firmware overhead. |
| Industrial Backplane Interface | Legacy System Bus Isolation |
Use Scenario: Interfacing PLC I/O modules to a central controller over a 20cm parallel backplane with noise margin constraints. IC Role / Device Role / Timing Role: Noise-immune address/data line driver with 6mA drive and 0.8V/2.0V input hysteresis. Use Value: Maintains signal integrity under EMI exposure while supporting hot-swap insertion via controlled 3-state activation. | Use Scenario: Isolating obsolete 8086-based subsystem from modern FPGA co-processor using shared data/address lines. IC Role / Device Role / Timing Role: Level-translating and contention-free bus buffer with TTL-compatible inputs and CMOS outputs. Use Value: Prevents bus lockup during reset sequencing by guaranteeing high-Z state on power-up before firmware initialization. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal inverting buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HCT240DWR | Identical electrical specs and SOIC-20 package; same pinout and marking (HCT240), differing only in tape-and-reel packaging (2000 vs 2000 units) and date code format | No functional difference; both rated for −40°C to +85°C operation and RoHS compliance | Select SN74HCT240DWR if requiring identical form-fit-function with alternate reel configuration or lot traceability preference |
| 74HCT240N | Same logic function and DC specs, but in PDIP-20 package (24.33mm × 9.4mm); higher thermal resistance (RθJA = 84.6°C/W vs 109.1°C/W for DW) | Suitable for prototyping or through-hole assembly; not recommended for high-density or thermally constrained PCBs | Choose 74HCT240N only for hand-soldered evaluation or legacy through-hole production where SOIC rework is impractical |
Compared with SN74HCT240DWR and 74HCT240N, SN74HCT240DWRE4 offers identical core functionality in the same SOIC-20 package but with TI's E4 suffix denoting enhanced quality screening and extended traceability-making it preferred for industrial OEM volume production where supply chain consistency matters.
Availability
SN74HCT240DWRE4 is available at Aetrix Electronics and suitable for industrial control backplanes, microcontroller I/O expansion, legacy system bus isolation, and memory address buffering requiring stable component supply across multi-year production cycles.
Supply support for SN74HCT240DWRE4 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 logic solutions with over 50 years of industrial-grade reliability validation.
The SN74HCT240DWRE4 belongs to TI's 74HCT logic family, engineered for 5V systems requiring TTL-compatible inputs, low power consumption, and robust 3-state bus driving in harsh industrial environments.
FAQ
What is the operating temperature range for SN74HCT240DWRE4?
SN74HCT240DWRE4 is rated for operation from −40°C to +85°C ambient temperature. This industrial-grade range is validated per TI's manufacturing test flow and supports deployment in factory automation, motor control, and outdoor instrumentation where thermal cycling occurs. The SOIC-20 package's RθJA of 109.1°C/W ensures safe junction temperatures under typical 5V/10mA load conditions.
Does SN74HCT240DWRE4 require external pull-up resistors on its outputs?
No, SN74HCT240DWRE4 does not require external pull-up resistors on its outputs. Its ±6mA output drive capability at 5V allows direct interfacing with 15 LSTTL loads, and its 3-state outputs present high impedance (IOZ ≤ ±5μA) when disabled-eliminating contention and pull-up dependencies in shared-bus configurations.
How does the inverting function of SN74HCT240DWRE4 affect system timing?
The inverting function of SN74HCT240DWRE4 adds no additional timing penalty beyond its specified 12ns typical propagation delay (tpd). Since inversion is inherent to the gate structure-not a separate logic stage-it does not increase setup/hold margins or require compensation in synchronous designs. The device's tpd, ten, and tdis values are all characterized with inversion included.
Can SN74HCT240DWRE4 be used with 3.3V microcontrollers?
SN74HCT240DWRE4 is not recommended for direct connection to 3.3V microcontrollers because its inputs require VIH ≥ 2.0V (TTL-compatible), which may be marginal with 3.3V logic high levels, and its outputs swing rail-to-rail at 5V-risking overvoltage damage to 3.3V inputs. Use level-shifting buffers like TXB0108 if interfacing with 3.3V systems.
What is the meaning of the 'E4' suffix in SN74HCT240DWRE4?
The 'E4' suffix in SN74HCT240DWRE4 denotes Texas Instruments' enhanced quality screening level, including extended burn-in, tighter parametric testing, and full traceability to wafer lot and assembly batch. It indicates suitability for industrial and automotive applications where long-term reliability and supply chain transparency are critical-distinct from standard 'DWR' variants.
SN74HCT240DWRE4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HCT
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- 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:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
SN74HCT240DWRE4 FAQ
1.How can I place an order for SN74HCT240DWRE4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74HCT240DWRE4 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 SN74HCT240DWRE4 reliable?
The price and inventory of SN74HCT240DWRE4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74HCT240DWRE4 is usually 5 days.
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SN74HCT240DWRE4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74HCT240DWRE4 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 SN74HCT240DWRE4?
For technical support, including SN74HCT240DWRE4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74HCT240DWRE4 requirements.
6.How does Aetrix verify that SN74HCT240DWRE4 is sourced from the original manufacturer or authorized distributors?
All SN74HCT240DWRE4 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 SN74HCT240DWRE4 meets industry standards.
7.What is the process for return or replacement of SN74HCT240DWRE4?
All SN74HCT240DWRE4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74HCT240DWRE4, 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 SN74HCT240DWRE4 part is unused and in its original packaging.
Return procedure for SN74HCT240DWRE4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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