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Texas Instruments SN74HC240DWG4
- Part No.:
- SN74HC240DWG4
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74HC240DWG4.pdf
- Description:
- IC BUFFER INVERT 6V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,156
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Product details
Overview
SN74HC240DWG4 from Texas Instruments is an octal inverting buffer/line driver with 3-state outputs, designed for memory address and bus driving applications. It operates across 2V–6V supply, delivers ±6mA output drive at 5V, exhibits typical propagation delay of 9ns, and consumes ≤80µA ICC - enabling high-density, low-power bus interfacing in industrial control and embedded systems.
For engineers reviewing the SN74HC240DWG4 datasheet, SN74HC240DWG4 pinout, SN74HC240DWG4 application, or SN74HC240DWG4 equivalent, key selection criteria include its dual 4-bit inverted 3-state architecture, SOIC-20 package compatibility, guaranteed 3-state enable timing (ten/tdis), and CMOS-level input thresholds aligned to LSTTL loads.
Technical Context
The SN74HC240DWG4 implements two independent 4-bit inverting buffers, each controlled by a dedicated output-enable (OE) input. When OE is low, data passes inverted from A inputs to Y outputs; when OE is high, all eight outputs enter high-impedance state - enabling bidirectional bus arbitration without external logic.
Its HC-family CMOS design ensures rail-to-rail output swing, low input current (≤1µA), and compatibility with both TTL and CMOS logic families. The device supports mixed-voltage system interfacing within its 2V–6V operating range and maintains stable switching performance up to 85°C ambient temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 2V to 6V - enables direct interface with 3.3V and 5V logic domains without level shifters |
| Output Drive | ±6mA at 5V - drives up to 15 LSTTL loads per output, supporting robust fanout in dense PCB layouts |
| Propagation Delay | 9ns typical at VCC = 4.5V, CL = 50pF - ensures sub-10ns timing margin for 50MHz bus clocking |
| ICC (Max) | 80µA at VCC = 6V - minimizes quiescent power in always-on control subsystems |
| Input Thresholds | VIH = 3.15V, VIL = 1.35V at VCC = 4.5V - provides 0.8V noise margin against LSTTL-compatible signals |
| 3-State Enable Time | ten = 25ns max at VCC = 4.5V - guarantees fast bus release for time-critical arbitration protocols |
Pinout & Package
SN74HC240DWG4 is housed in a 20-pin SOIC (DW) package measuring 12.80mm × 10.3mm (body: 12.80mm × 7.50mm), RoHS-compliant with NIPDAU lead finish and Level-1 MSL rating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | 1OE, 2OE | Active-low enable inputs controlling respective 4-bit buffer groups - asserted low to activate inverted output |
| 2–4, 6–8, 11–13, 15–17 | 1A1–1A4, 2A1–2A4 | Eight digital inputs accepting CMOS/TTL logic levels - each paired with corresponding inverted output |
| 3–5, 7, 9, 12, 14, 16, 18 | 1Y1–1Y4, 2Y1–2Y4 | Eight inverted 3-state outputs - high-impedance when OE is high, enabling shared bus topology |
| 10 | GND | Ground reference for all internal circuitry and output drivers - requires low-inductance connection to system ground plane |
| 20 | VCC | Primary power supply pin - must be decoupled with 0.1µF ceramic capacitor placed adjacent to pin |
Key Features
| Feature | Design Value |
|---|---|
| Inverting 3-State Output Architecture | Two independent 4-bit groups with separate OE pins allow selective bus isolation and polarity inversion without external inverters |
| Wide Supply Range | 2V–6V operation supports interoperability across legacy 5V and modern 3.3V/2.5V subsystems in mixed-voltage designs |
| Low-Power CMOS Design | 80µA max ICC enables use in battery-backed or energy-constrained control modules without thermal derating |
| High-Noise-Immunity Inputs | Guaranteed VIH/VIL margins exceed LSTTL requirements, reducing susceptibility to crosstalk in high-speed routing |
| Fast 3-State Switching | 25ns max enable/disable times ensure minimal bus contention during dynamic reconfiguration in real-time systems |
Applications
| Memory Address Buffering | Industrial Bus Transceiver |
|---|---|
Use Scenario: Driving 16-bit address lines from a microcontroller to multiple SRAM or EPROM devices on a shared memory bus. IC Role / Device Role / Timing Role: Inverting 3-state buffer isolating address latches and enabling multi-drop memory decoding. Use Value: Eliminates need for discrete inverters and pull-up resistors while maintaining <9ns propagation delay for synchronous access timing. | Use Scenario: Interfacing PLC I/O modules to a central controller via a daisy-chained RS-485 or CAN physical layer bus. IC Role / Device Role / Timing Role: Direction-controlled signal conditioning stage buffering control signals between isolated communication ICs and local logic. Use Value: Provides clean, high-drive buffered signals with precise 3-state timing to prevent bus collisions during half-duplex transitions. |
| Legacy System Logic Translation | Test Equipment Signal Routing |
Use Scenario: Adapting TTL-level control signals from aging instrumentation hardware to modern 3.3V FPGA-based test sequencers. IC Role / Device Role / Timing Role: Level-shifting and fanout buffer translating 5V logic to 3.3V-compatible inputs while preserving signal integrity. Use Value: Achieves voltage translation without external biasing networks, leveraging native 2V–6V supply tolerance and 1µA input leakage. | Use Scenario: Multiplexing stimulus signals from a pattern generator to multiple DUT channels in automated test equipment. IC Role / Device Role / Timing Role: 3-state-enabled signal distributor enabling dynamic channel selection without mechanical relays. Use Value: Reduces switching transients and layout complexity versus relay-based routing, with sub-30ns enable timing for synchronized test vector delivery. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal inverting buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HC240PWRG4 | TSSOP-20 package (6.50mm × 6.4mm); identical electrical specs and pinout | Better suited for space-constrained PCBs requiring higher component density | Select when board area is limited and reflow compatibility with fine-pitch TSSOP is confirmed |
| SN74HCT240N | TTL-compatible input thresholds (VIH = 2.0V min); same SOIC-20 footprint | Preferred in legacy 5V-only systems with marginal noise margins or slow-rising signals | Choose when interfacing with older TTL logic where HC input thresholds may cause metastability |
Compared with SN74HC240PWRG4, SN74HC240DWG4 offers larger SOIC pads for easier manual soldering and thermal relief; versus SN74HCT240N, it provides superior noise immunity in mixed-signal environments but requires stricter input rise/fall time compliance.
Availability
SN74HC240DWG4 is available at Aetrix Electronics and suitable for industrial automation, test equipment, and legacy system upgrades requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.
Supply support for SN74HC240DWG4 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 for industrial, automotive, and communications markets.
The SN74HC240DWG4 belongs to TI's 74HC logic family, engineered for high-speed, low-power 3-state bus interfacing in memory, clock, and control applications where density and reliability are critical.
FAQ
What is the function of the OE pins on SN74HC240DWG4?
The SN74HC240DWG4 features two active-low output-enable pins: 1OE (Pin 1) controls the first 4-bit inverting buffer group (1A1–1A4 → 1Y1–1Y4), and 2OE (Pin 19) controls the second group (2A1–2A4 → 2Y1–2Y4). When either OE is low, its associated outputs drive inverted input data; when high, those outputs enter high-impedance state. This allows independent bus segment control - essential for multiplexed memory or peripheral addressing. The SN74HC240DWG4 datasheet specifies ten = 25ns max enable time at 4.5V.
Does SN74HC240DWG4 support 3.3V operation?
Yes, SN74HC240DWG4 fully supports 3.3V operation within its specified 2V–6V supply range. At VCC = 3.3V, it delivers guaranteed VOH ≥ 3.15V and VOL ≤ 0.1V under 6mA load, meeting standard 3.3V CMOS logic thresholds. Input thresholds scale proportionally (VIH ≈ 2.31V, VIL ≈ 0.99V), providing >0.7V noise margin. The SN74HC240DWG4 is widely deployed in mixed-voltage systems interfacing 3.3V FPGAs with 5V peripherals.
What is the maximum capacitive load SN74HC240DWG4 can drive reliably?
SN74HC240DWG4 is characterized for CL = 50pF and 150pF loads in its switching specifications. At 4.5V supply, tpd increases from 25ns (50pF) to 38ns (150pF), remaining within functional timing budgets for most bus applications. While not explicitly rated beyond 150pF, empirical use shows stable operation up to ~200pF with minor delay degradation. For designs exceeding 150pF, verify setup/hold margins using the SN74HC240DWG4's published tt (output transition time) and tpd values in the actual system configuration.
How does SN74HC240DWG4 differ from SN74HC244?
SN74HC240DWG4 is an inverting octal buffer (A → Y inversion), whereas SN74HC244 is non-inverting. Both share identical 20-pin SOIC packaging, 3-state architecture, and electrical specs (drive strength, delay, supply range). The core functional difference lies in signal polarity: SN74HC240DWG4 flips logic states on pass-through, making it suitable for complemented address/data paths or active-low enable schemes; SN74HC244 preserves polarity. Pinouts differ - SN74HC240DWG4 uses dual OE inputs and interleaved I/O, while SN74HC244 has single OE and grouped I/O.
Is SN74HC240DWG4 pin-compatible with older 74LS240 devices?
No, SN74HC240DWG4 is not pin-compatible with 74LS240. Although both are octal inverting 3-state buffers in 20-pin packages, their pin assignments differ significantly: 74LS240 places GND at Pin 10 and VCC at Pin 20 (same), but assigns 1A1 to Pin 1 (not Pin 2) and 1Y1 to Pin 18 (not Pin 3). Attempting direct replacement would cause incorrect signal routing and potential bus contention. The SN74HC240DWG4 follows TI's standardized HC-series pinout defined in SCLS128H, not the legacy LS layout.
SN74HC240DWG4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HC
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Logic Type:
- Buffer, Inverting
- Number of Elements:
- 2
- Number of Bits per Element:
- 4
- Input Type:
- -
- Output Type:
- 3-State
- Current - Output High, Low:
- 7.8mA, 7.8mA
- Voltage - Supply:
- 2V ~ 6V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
SN74HC240DWG4 FAQ
1.How can I place an order for SN74HC240DWG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74HC240DWG4 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 SN74HC240DWG4 reliable?
The price and inventory of SN74HC240DWG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74HC240DWG4 is usually 5 days.
3.What payment methods are accepted for SN74HC240DWG4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74HC240DWG4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74HC240DWG4?
SN74HC240DWG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74HC240DWG4 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 SN74HC240DWG4?
For technical support, including SN74HC240DWG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74HC240DWG4 requirements.
6.How does Aetrix verify that SN74HC240DWG4 is sourced from the original manufacturer or authorized distributors?
All SN74HC240DWG4 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 SN74HC240DWG4 meets industry standards.
7.What is the process for return or replacement of SN74HC240DWG4?
All SN74HC240DWG4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74HC240DWG4, 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 SN74HC240DWG4 part is unused and in its original packaging.
Return procedure for SN74HC240DWG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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