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Texas Instruments SN74ACT240NS
- Part No.:
- SN74ACT240NS
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
SN74ACT240NS.pdf
- Description:
- PROTOTYPE
- Quantity:
- Payment:
- Shipping:
Inventory:1,257
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Product details
Overview
SN74ACT240NS from Texas Instruments is an octal 3-state inverting buffer/driver IC designed for memory address, clock, and bus interface applications. It operates from 4.5 V to 5.5 V, features TTL-compatible inputs, delivers ≤8.5 ns propagation delay at 5 V, and supports ±24 mA output drive - enabling robust signal conditioning in high-density digital systems such as network switches and smartphone baseband subsystems.
For engineers reviewing the SN74ACT240NS datasheet, SN74ACT240NS pinout, SN74ACT240NS application, or SN74ACT240NS equivalent, this page provides verified functional identity, package-specific pin mapping (SOP-20), switching and DC electrical specifications, real-world use context, and validated alternative options for bus buffering and level translation tasks.
Technical Context
The SN74ACT240NS implements two independent 4-bit inverting buffer sections, each with dedicated 3-state output-enable (OE) control. Its balanced CMOS push-pull outputs provide symmetrical sourcing and sinking capability up to ±24 mA per channel under recommended operating conditions.
It functions as a dual quad-channel inverter with high-impedance (Z) output state controlled by active-low OE signals. Input voltage tolerance extends to 5.5 V regardless of VCC, supporting mixed-voltage interfacing, while its 20-pin SOP package enables compact placement on space-constrained PCBs used in wearables and embedded communications hardware.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.5 V to 5.5 V - ensures compatibility with standard 5 V logic rails and tolerates supply variation without functional degradation. |
| Max tpd | 8.5 ns at 5 V - enables reliable operation in high-speed address/data bus timing paths up to ~115 MHz. |
| IOH/IOL | ±24 mA - supports direct driving of multiple TTL loads or moderate-capacitance traces without external buffers. |
| Input Compatibility | TTL-compatible - accepts standard 0.8 V/2.0 V logic thresholds, simplifying integration with legacy 5 V microcontrollers and FPGAs. |
| Output State Control | Active-low 3-state OE per section - allows bidirectional bus sharing and prevents contention during system reset or power sequencing. |
| Operating Temperature | –40 °C to +85 °C - qualified for industrial and consumer-grade applications including network infrastructure and handheld devices. |
Pinout & Package
SOP-20 (Small Outline Package, 12.6 mm × 7.8 mm body size) with gull-wing leads and standard JEDEC pin 1 index marking.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1OE | Input | Active-low enable for first 4-bit inverting buffer section (controls Y1–Y4 outputs). |
| 1A1–1A4 | Inputs | Inverting data inputs for first section; low-to-high transition yields high-to-low output on corresponding Y pins. |
| 1Y1–1Y4 | Outputs | Inverted buffered outputs for first section; enter high-impedance state when 1OE = high. |
| 2OE | Input | Active-low enable for second 4-bit inverting buffer section (controls Y1–Y4 of second group). |
| 2A1–2A4 | Inputs | Inverting data inputs for second section; functionally identical to 1A1–1A4 but electrically isolated. |
| 2Y1–2Y4 | Outputs | Inverted buffered outputs for second section; independently controllable via 2OE. |
| VCC (Pin 20) | Power | Positive supply rail; must be decoupled locally with 0.1 µF ceramic capacitor near pin. |
| GND (Pin 10) | Ground | Reference return path; connects to system ground plane to minimize noise coupling into sensitive logic paths. |
Key Features
| Feature | Design Value |
|---|---|
| Inverting 3-state buffer architecture | Dual independent 4-bit sections allow selective bus isolation and direction control without external logic. |
| High-speed CMOS process | 8.5 ns max propagation delay enables use in 5 V systems requiring sub-10 ns timing margins. |
| 5.5 V-tolerant inputs | Permits safe interfacing with higher-voltage peripherals or open-drain pull-ups without level-shifting circuitry. |
| Balanced output drive | ±24 mA sourcing/sinking symmetry reduces ground bounce and improves signal integrity on shared buses. |
| Industrial temperature range | –40 °C to +85 °C operation supports deployment in uncontrolled environments like telecom edge nodes and portable electronics. |
Applications
| Smartphone Baseband Interface | Network Switch Address Bus |
|---|---|
|
Use Scenario: Isolating and buffering memory-mapped peripheral addresses between AP and modem SoC in dual-processor handset architectures. IC Role / Device Role / Timing Role: Inverting 3-state buffer providing direction-controlled address latching and contention-free bus arbitration. Use Value: Enables clean separation of AP/modem address domains while maintaining <8.5 ns timing compliance for DDR2/SDRAM access cycles. |
Use Scenario: Driving parallel address lines from switch fabric controller to multiple PHY register banks in Layer 2/L3 Ethernet switches. IC Role / Device Role / Timing Role: Octal inverting driver delivering synchronized, slew-controlled address transitions across 20+ cm trace lengths. Use Value: Eliminates need for discrete gate arrays; ±24 mA drive sustains signal integrity over FR-4 backplanes with ≤15 pF load per line. |
| Wearable Sensor Hub Interface | Industrial PLC I/O Expansion Module |
|
Use Scenario: Level-translating and buffering I²C/SPI address bits between ultra-low-power MCU and multi-sensor array in fitness tracker. IC Role / Device Role / Timing Role: Voltage-tolerant buffer allowing 5 V sensor addressing from 3.3 V host while preserving timing margins. Use Value: Reduces BOM count by replacing discrete level shifters; 5.5 V input tolerance avoids additional protection diodes. |
Use Scenario: Multiplexing digital I/O configuration registers between main CPU and modular expansion slots in programmable logic controllers. IC Role / Device Role / Timing Role: Dual-section 3-state buffer enabling hot-swappable module detection and dynamic address assignment. Use Value: Independent OE control permits runtime reconfiguration without bus lockup; industrial temp rating ensures reliability in cabinet-mounted designs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal inverting buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ACT244NS | Non-inverting output logic (A→Y); otherwise identical VCC, speed, drive, and package. | Used where signal polarity preservation is required (e.g., data bus drivers), not address inversion. | Select SN74ACT244NS when system logic requires true (non-inverted) buffering rather than complemented outputs. |
| SN74LS240N | Lower drive (±15 mA), slower (tpd ≤ 25 ns), TTL-input only, 7 V max VCC; PDIP-20 only. | Legacy 5 V systems with relaxed timing budgets and no 5.5 V tolerance requirement. | Choose SN74LS240N only for backward compatibility in existing LS-based designs where speed and voltage margin are secondary. |
Compared with SN74ACT240NS, SN74ACT244NS offers identical performance with non-inverting logic for data-path applications, while SN74LS240N trades speed and voltage flexibility for legacy TTL interoperability - making SN74ACT240NS optimal for new 5 V designs needing fast, robust, polarity-aware bus control.
Availability
SN74ACT240NS is available at Aetrix Electronics and suitable for network switch address buffering, smartphone baseband interface, and industrial PLC I/O expansion requiring stable component supply and long-term production continuity.
Supply support for SN74ACT240NS 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 90 years of innovation in high-reliability electronic components.
The SNx4ACT240 family was engineered for high-speed, low-noise bus interfacing in memory, clock, and peripheral subsystems - targeting density-optimized 5 V digital systems where precise timing, drive strength, and 3-state control are critical.
FAQ
What is the logic function of SN74ACT240NS?
The SN74ACT240NS implements two independent 4-bit inverting 3-state buffers. Each section inverts input signals (A→Y) when its respective output-enable (OE) pin is low; outputs go high-impedance when OE is high. This behavior is confirmed in the device functional mode table and logic diagram of the official TI datasheet SCAS515G.
Does SN74ACT240NS support 5 V tolerant inputs?
Yes, SN74ACT240NS accepts input voltages up to 5.5 V regardless of VCC level, as specified in Section 5.1 (Absolute Maximum Ratings) and Section 5.2 (Recommended Operating Conditions) of the TI datasheet. This allows safe interfacing with 5 V peripherals even when powered from lower VCC rails.
What is the maximum propagation delay for SN74ACT240NS at 5 V?
The maximum propagation delay (tpd) for SN74ACT240NS is 8.5 ns at VCC = 5 V and TA = 25 °C, per Section 5.5 (Switching Characteristics) of the TI datasheet SCAS515G. This value applies to both tPLH and tPHL under standard load conditions.
Can SN74ACT240NS drive multiple TTL loads directly?
Yes, SN74ACT240NS can drive up to 10 standard TTL loads per output due to its ±24 mA output current capability (IOH/IOL), as specified in Section 5.2. This eliminates the need for additional fanout buffers in typical 5 V bus applications.
Is SN74ACT240NS pin-compatible with other packages in the SN74ACT240 family?
No - SN74ACT240NS uses the SOP-20 (NS) package with 12.6 mm × 7.8 mm body size and specific lead pitch/geometry. While functional and electrical specs are consistent across packages, mechanical dimensions, thermal characteristics, and PCB land patterns differ; migration requires layout revision. Pin numbering matches JEDEC MS-012 for SOP-20.
SN74ACT240NS Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ACT
- Package/Case:
- 20-SOIC (0.209", 5.30mm 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:
- 24mA, 24mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SO
SN74ACT240NS FAQ
1.How can I place an order for SN74ACT240NS through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ACT240NS 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 SN74ACT240NS reliable?
The price and inventory of SN74ACT240NS are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ACT240NS is usually 5 days.
3.What payment methods are accepted for SN74ACT240NS?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74ACT240NS transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74ACT240NS?
SN74ACT240NS orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ACT240NS 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 SN74ACT240NS?
For technical support, including SN74ACT240NS datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ACT240NS requirements.
6.How does Aetrix verify that SN74ACT240NS is sourced from the original manufacturer or authorized distributors?
All SN74ACT240NS 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 SN74ACT240NS meets industry standards.
7.What is the process for return or replacement of SN74ACT240NS?
All SN74ACT240NS units undergo pre-shipment inspection (PSI). If there is an issue with SN74ACT240NS, 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 SN74ACT240NS part is unused and in its original packaging.
Return procedure for SN74ACT240NS:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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