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Texas Instruments SN74F240N
- Part No.:
- SN74F240N
- Manufacturer:
- Texas Instruments
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
SN74F240N.pdf
- Description:
- IC BUFFER INVERT 5.5V 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:437
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Product details
Overview
SN74F240N from Texas Instruments is an octal noninverting buffer/driver with dual 4-bit sections and independent active-low 3-state output-enable (OE) inputs, operating at 4.5–5.5 V, delivering 64 mA low-level output current and supporting bus driving and memory address register buffering in TTL-compatible systems.
For engineers reviewing the SN74F240N datasheet, SN74F240N pinout, SN74F240N application, or SN74F240N equivalent, key selection criteria include its 20-pin PDIP package, 0°C to 70°C industrial temperature range, 3.1 ns typical tPHL propagation delay, high-impedance output state control, and compatibility with legacy F-series TTL logic families.
Technical Context
The SN74F240N implements two independent 4-bit noninverting buffer sections, each with dedicated active-low OE input controlling high-impedance output states. Its architecture supports bidirectional bus isolation and unidirectional address/data path buffering without signal inversion.
It uses standard bipolar F-series TTL process technology, ensuring compatibility with SN74F241 (inverting) and SN74F244 (noninverting, shared OE) for flexible memory and clock driver configurations. Input thresholds meet TTL VIH ≥ 2.0 V and VIL ≤ 0.8 V specifications under recommended operating conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - ensures stable operation across standard 5 V ±10% power rails |
| Output Drive (IOL) | 64 mA - sufficient to drive multiple TTL loads or terminate short PCB traces |
| Propagation Delay (tPHL) | 1.2–5.7 ns - enables high-speed address/data buffering in 20–30 MHz system buses |
| 3-State Leakage (IOZL) | –50 µA - guarantees minimal bus contention during output disable |
| Operating Temperature | 0°C to 70°C - qualified for commercial/industrial embedded control and instrumentation |
| Input Thresholds | VIH ≥ 2.0 V, VIL ≤ 0.8 V - maintains robust noise margin against TTL logic levels |
| Package Type | 20-pin PDIP (N) - through-hole mounting compatible with legacy prototyping and repair workflows |
Pinout & Package
SN74F240N is housed in a 20-pin plastic dual in-line package (PDIP), 0.300-inch wide body, with standard DIP pin spacing (0.100 inch). Pin 1 is located at the top-left corner when viewed from the top with notch or dot orientation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1OE | Section 1 Output Enable (active-low) | Controls Y1–Y4 outputs; low = enabled, high = high-Z |
| 1A1–1A4 | Section 1 Data Inputs | Noninverting inputs feeding outputs 1Y1–1Y4 |
| 1Y1–1Y4 | Section 1 Buffered Outputs | 3-state noninverting outputs, driven only when 1OE = L |
| GND | Ground Reference | Pin 10 - primary return path for all internal logic and output currents |
| VCC | Positive Supply | Pin 20 - powers internal circuitry and output drivers at 4.5–5.5 V |
| 2OE | Section 2 Output Enable (active-low) | Controls Y1–Y4 of second section; independent of 1OE |
| 2A1–2A4 | Section 2 Data Inputs | Noninverting inputs feeding outputs 2Y1–2Y4 |
| 2Y1–2Y4 | Section 2 Buffered Outputs | 3-state noninverting outputs, driven only when 2OE = L |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent 4-bit sections | Enables separate control of two address/data groups without interdependence |
| Active-low 3-state OE per section | Allows precise timing-controlled bus release without external gating logic |
| TTL-compatible input/output levels | Direct drop-in replacement for legacy 74LS/74S240 in existing designs |
| High sink current (64 mA) | Drives up to 10 standard TTL loads per output, reducing need for external buffers |
| Low propagation delay (≤5.7 ns) | Supports reliable operation in 20+ MHz address latching and bus arbitration cycles |
Applications
| Memory Address Buffering | System Bus Driver |
|---|---|
|
Use Scenario: Isolating microprocessor address lines from multiple memory chips on a shared bus. IC Role / Device Role / Timing Role: Noninverting buffer with per-section 3-state control, enabling dynamic address routing without contention. Use Value: Prevents bus conflicts during memory bank switching while maintaining TTL-level timing integrity. |
Use Scenario: Driving shared data/control lines between CPU, peripherals, and I/O expanders. IC Role / Device Role / Timing Role: Bidirectional bus driver with independent enable control for read/write direction management. Use Value: Eliminates need for discrete transceivers by providing controlled high-Z states synchronized to bus cycle timing. |
| Legacy System Upgrade | Industrial Control Backplane |
|
Use Scenario: Replacing obsolete 74LS240 in field-repairable industrial controllers. IC Role / Device Role / Timing Role: Pin-compatible TTL buffer with improved drive strength and speed over LS family. Use Value: Extends service life of aging hardware without PCB redesign or timing validation overhead. |
Use Scenario: Buffering sensor interface signals across long backplane traces in PLC racks. IC Role / Device Role / Timing Role: Signal conditioner that restores edge integrity and drives capacitive loads up to 50 pF. Use Value: Maintains setup/hold margins despite trace-induced skew and noise in noisy factory environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal noninverting buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LS240N | Slower (tPHL ≤ 15 ns), lower drive (IOL = 24 mA), higher ICC (19 mA active) | Compatible in static logic but marginal for >10 MHz bus operation | Choose for cost-sensitive legacy replacements where speed is not critical |
| SN74F244N | Shared OE inputs (not independent per section); otherwise identical electrical specs | Requires consolidated enable control; unsuitable for split-bus architectures | Choose when both sections must be enabled/disabled simultaneously to simplify glue logic |
Compared with SN74LS240N and SN74F244N, the SN74F240N uniquely balances speed, drive strength, and per-section 3-state control-making it optimal for dynamic bus partitioning in memory-mapped systems where timing and isolation are co-constrained.
Availability
SN74F240N is available at Aetrix Electronics and suitable for industrial control panels, legacy test equipment upgrades, and military-grade system sustainment requiring stable component supply and long-term obsolescence mitigation.
Supply support for SN74F240N 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 founded in 1930, specializing in analog, embedded processing, and logic solutions with broad industrial, automotive, and aerospace qualification.
The SN74F240N belongs to TI's 74F TTL logic family, designed specifically for high-speed, high-drive memory addressing and bus interfacing in systems where LS-family timing margins were insufficient.
FAQ
What is the maximum operating temperature range for the SN74F240N?
The SN74F240N is characterized for operation from 0°C to 70°C, meeting commercial and industrial ambient requirements. It is not rated for extended temperature ranges like the military-grade SN54F240 (–55°C to 125°C), and operation outside 0–70°C may result in undefined timing or output behavior.
Does the SN74F240N support mixed-voltage interfacing, such as 3.3 V inputs?
No-the SN74F240N is a standard 5 V TTL device with VIH minimum of 2.0 V and VIL maximum of 0.8 V. While 3.3 V logic outputs may exceed VIH, they lack guaranteed noise margin and risk marginal operation; level-shifting or 5 V-compatible drivers are required for reliable interfacing.
Can the SN74F240N replace the SN74LS240N in an existing design without modifications?
Yes-SN74F240N is pin-compatible and functionally identical to SN74LS240N, with faster propagation delays (≤5.7 ns vs. ≤15 ns) and higher output drive (64 mA vs. 24 mA). No PCB changes are needed, though timing analysis should confirm setup/hold margins benefit from the improved speed.
What is the purpose of the two separate OE inputs (1OE and 2OE) on the SN74F240N?
The dual OE inputs allow independent control of the two 4-bit buffer sections. This enables selective activation-for example, driving upper/lower memory banks separately or isolating data paths during DMA transfers-without requiring additional logic gates or multiplexers in the enable path.
Is the SN74F240N RoHS compliant?
Yes-the SN74F240N is RoHS compliant with lead-free NiPdAu (NIPDAU) terminal finish, as confirmed in TI's official packaging addendum. It meets EU Directive 2011/65/EU and is suitable for environmentally regulated production environments.
SN74F240N Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74F
- Package/Case:
- 20-DIP (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:
- 15mA, 64mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 20-PDIP
SN74F240N FAQ
1.How can I place an order for SN74F240N through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74F240N 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 SN74F240N reliable?
The price and inventory of SN74F240N are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74F240N is usually 5 days.
3.What payment methods are accepted for SN74F240N?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74F240N transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74F240N?
SN74F240N orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74F240N 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 SN74F240N?
For technical support, including SN74F240N datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74F240N requirements.
6.How does Aetrix verify that SN74F240N is sourced from the original manufacturer or authorized distributors?
All SN74F240N 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 SN74F240N meets industry standards.
7.What is the process for return or replacement of SN74F240N?
All SN74F240N units undergo pre-shipment inspection (PSI). If there is an issue with SN74F240N, 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 SN74F240N part is unused and in its original packaging.
Return procedure for SN74F240N:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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