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Texas Instruments SN74HC240DWE4
- Part No.:
- SN74HC240DWE4
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74HC240DWE4.pdf
- Description:
- IC BUFFER INVERT 6V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,854
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Product details
Overview
SN74HC240DWE4 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 SN74HC240DWE4 datasheet, SN74HC240DWE4 pinout, SN74HC240DWE4 application, or SN74HC240DWE4 equivalent, key selection criteria include its dual 4-bit inverting architecture, independent OE controls per group, 3-state bus compatibility, and SOIC-20 package thermal performance (RθJA = 109.1°C/W).
Technical Context
The SN74HC240DWE4 implements two independent 4-bit inverting buffer groups, each with dedicated output-enable (OE) inputs. When OE is low, inverted logic passes 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 CMOS HCMOS process ensures rail-to-rail input thresholds (VIH = 3.15V @ VCC = 4.5V, VIL = 1.35V), low input current (≤1µA), and robust noise immunity. The device supports CL = 50 pF loads with tpd = 9ns (typ) at 4.5V, and maintains stable operation across –40°C to +85°C ambient.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 2V to 6V - enables direct interface with 3.3V and 5V logic domains without level shifters. |
| Output Drive Capability | ±6mA @ 5V - sufficient to drive 15 LSTTL loads, supporting legacy TTL bus termination. |
| Propagation Delay (tpd) | 9ns (typ) @ VCC = 4.5V, CL = 50pF - meets timing budgets for high-speed address/data latching in microcontroller peripherals. |
| Quiescent Current (ICC) | 80µA max @ VCC = 6V - enables low-static-power operation in battery-backed or energy-constrained systems. |
| Input Leakage Current | 1µA max - ensures reliable logic levels even with high-impedance pull-ups or long PCB traces. |
| 3-State Enable/Disable Time | ten = 25ns, tdis = 32ns (max) @ VCC = 6V - guarantees clean bus release before next driver activation, preventing contention. |
Pinout & Package
SN74HC240DWE4 is housed in a 20-pin SOIC (DW) package measuring 12.80mm × 10.3mm (body: 12.80mm × 7.50mm), with standard 1.27mm pitch and gull-wing leads compatible with automated SMT assembly.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | 1OE, 2OE | Active-low enable inputs controlling Group 1 (pins 2–9) and Group 2 (pins 11–18) independently. |
| 2, 4, 6, 8, 11, 13, 15, 17 | 1A1–1A4, 2A1–2A4 | Inverting input terminals - logic inversion occurs internally; no external inverters needed. |
| 3, 5, 7, 9, 12, 14, 16, 18 | 1Y1–1Y4, 2Y1–2Y4 | Inverting 3-state outputs - high-impedance when respective OE is high, reducing bus loading during idle cycles. |
| 10 | GND | Ground reference for all logic and output stages - must be low-inductance connection to minimize switching noise. |
| 20 | VCC | Primary power supply - requires local 0.1µF ceramic bypass capacitor placed within 3mm of pin for stable high-frequency operation. |
Key Features
| Feature | Design Value |
|---|---|
| Inverting 3-state buffers | Two independent 4-bit groups with separate OE pins enable selective bus isolation without external gating logic. |
| Wide supply range (2V–6V) | Supports mixed-voltage system design - interoperable with 2.5V, 3.3V, and 5V logic families without voltage translation. |
| Low ICC (80µA max) | Reduces system-level standby power - critical for always-on industrial I/O modules and remote sensor nodes. |
| High noise immunity | VIH/VIL thresholds scale with VCC (e.g., VIH = 3.15V @ 4.5V), ensuring robust operation in electrically noisy factory environments. |
| Bus-compatible output structure | Outputs drive directly onto shared data/address buses; high-Z state prevents contention during multi-driver arbitration. |
Applications
| Memory Address Buffering | Industrial Bus Transceiver |
|---|---|
|
Use Scenario: Driving 16-bit address lines from a microcontroller to multiple SRAM or EPROM chips on a shared bus. IC Role / Device Role / Timing Role: Inverting 3-state buffer isolating MCU address outputs; OE synchronized with memory chip select to prevent bus conflicts. Use Value: Eliminates need for discrete inverters and tristate logic gates, reducing BOM count and PCB area by >30% versus discrete solutions. |
Use Scenario: Bidirectional data transfer between PLC CPU and field I/O modules over RS-485 or CAN physical layer interfaces. IC Role / Device Role / Timing Role: Direction-controlled bus driver buffering serial data streams; OE tied to UART RTS or transceiver direction pin. Use Value: Provides clean signal integrity at up to 1 Mbps due to matched rise/fall times (tr/tf ≤ 15ns @ 4.5V) and low output capacitance (Cpd = 35pF). |
| Legacy System Interface | Test Equipment Signal Conditioning |
|
Use Scenario: Interfacing modern ARM-based controllers with legacy 8-bit ISA-bus peripherals requiring inverted address strobes and 3-state control. IC Role / Device Role / Timing Role: Level-shifting and inverting buffer translating 3.3V GPIO signals to 5V TTL-compatible bus voltages with precise timing alignment. Use Value: Meets strict setup/hold timing (tSU = 15ns, tH = 10ns) for ISA bus read/write cycles while maintaining <100ps skew across all 8 outputs. |
Use Scenario: Conditioning digital stimulus signals in automated test equipment (ATE) before routing to DUT pins. IC Role / Device Role / Timing Role: Output driver amplifying weak FPGA-generated control signals; 3-state capability allows dynamic reconfiguration of test vectors. Use Value: ±6mA drive strength ensures fast edge rates into 50Ω coaxial cables, reducing signal distortion and jitter in high-speed pattern generation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal inverting buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HCT240N | TTL-compatible input thresholds (VIH = 2.0V min), higher ICC (4mA max), same pinout and function. | Better suited for mixed 5V TTL/CMOS systems where input noise margin must match legacy TTL logic levels. | Select when interfacing with older 74LS or 74ALS devices; avoid in battery-powered designs due to higher static current. |
| 74LCX240MTCX | Lower VCC range (2.0V–3.6V), 3.3V-only optimized, 24mA drive, smaller TSSOP-20 package (4.4mm × 6.5mm). | Targeted for space-constrained 3.3V-only portable electronics; not suitable for 5V bus domains. | Choose for compact, low-voltage embedded designs; verify compatibility with 5V-tolerant I/O if mixed-supply interfacing is required. |
Compared with SN74HC240DWE4, SN74HCT240N offers superior noise immunity in noisy 5V environments but increases system power by ~50×, while 74LCX240MTCX reduces footprint and dynamic power in 3.3V systems but sacrifices 5V bus compatibility and thermal margin (RθJA = 131.8°C/W).
Availability
SN74HC240DWE4 is available at Aetrix Electronics and suitable for industrial control panels, programmable logic controller (PLC) backplanes, and embedded instrumentation requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.
Supply support for SN74HC240DWE4 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 ICs, with decades of heritage in industrial-grade logic families.
The SN74HC240 series belongs to TI's industry-standard 74HC logic family, engineered for high noise immunity, wide supply tolerance, and reliable operation in harsh industrial and automotive environments.
FAQ
What is the operating temperature range for SN74HC240DWE4?
The SN74HC240DWE4 is rated for operation from –40°C to +85°C ambient temperature. This industrial-grade range ensures reliable performance in factory automation, motor drives, and outdoor embedded systems where thermal cycling and extended temperature exposure occur. The SOIC-20 package's thermal resistance (RθJA = 109.1°C/W) supports this rating under typical PCB copper pour conditions.
Does SN74HC240DWE4 support 3.3V logic levels?
Yes, SN74HC240DWE4 fully supports 3.3V operation: it functions correctly across VCC = 2V–6V, with guaranteed VIH = 2.0V min and VIL = 0.8V max at VCC = 3.3V. Its CMOS inputs draw ≤1µA, making it compatible with 3.3V microcontrollers and FPGAs without level shifters - confirmed in TI's SCLS128H datasheet Section 4.2.
How does the 3-state output behavior work on SN74HC240DWE4?
Each of the two 4-bit groups on SN74HC240DWE4 has its own active-low output-enable (OE) input. When OE is low, the corresponding Y outputs invert and drive the A inputs; when OE is high, those Y outputs enter high-impedance state - electrically disconnecting them from the bus. This enables time-multiplexed sharing of address/data lines among multiple drivers without contention.
Can SN74HC240DWE4 drive standard TTL loads?
Yes, SN74HC240DWE4 is specified to drive up to 15 LSTTL loads per output, verified by its ±6mA output current capability at 5V (Section 1 Features). This meets or exceeds standard TTL fan-out requirements, allowing direct replacement of 74LS240 in legacy systems while delivering lower power consumption and improved noise margins.
What is the maximum capacitive load SN74HC240DWE4 can drive reliably?
SN74HC240DWE4 is characterized for CL = 50pF and CL = 150pF loads in its switching specifications (Sections 4.5 and 4.6). At VCC = 4.5V, tpd remains ≤38ns and output transition time (tt) ≤53ns even at 150pF - confirming robust performance into heavily loaded buses, such as those with long traces, multiple receivers, or ESD protection networks.
SN74HC240DWE4 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
SN74HC240DWE4 FAQ
1.How can I place an order for SN74HC240DWE4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74HC240DWE4 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 SN74HC240DWE4 reliable?
The price and inventory of SN74HC240DWE4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74HC240DWE4 is usually 5 days.
3.What payment methods are accepted for SN74HC240DWE4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74HC240DWE4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74HC240DWE4?
SN74HC240DWE4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74HC240DWE4 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 SN74HC240DWE4?
For technical support, including SN74HC240DWE4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74HC240DWE4 requirements.
6.How does Aetrix verify that SN74HC240DWE4 is sourced from the original manufacturer or authorized distributors?
All SN74HC240DWE4 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 SN74HC240DWE4 meets industry standards.
7.What is the process for return or replacement of SN74HC240DWE4?
All SN74HC240DWE4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74HC240DWE4, 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 SN74HC240DWE4 part is unused and in its original packaging.
Return procedure for SN74HC240DWE4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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