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Texas Instruments SN74ACT240N
- Part No.:
- SN74ACT240N
- Manufacturer:
- Texas Instruments
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
SN74ACT240N.pdf
- Description:
- IC BUFF INVERT 5.5V 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:11,062
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Product details
Overview
SN74ACT240N from Texas Instruments is an octal 3-state inverting buffer/driver IC designed for bus-oriented data transmission, memory address driving, and clock distribution. It operates from 4.5 V to 5.5 V, supports TTL-compatible inputs up to 5.5 V, delivers ≤8.5 ns propagation delay at 5 V, and drives ±24 mA outputs - enabling robust signal integrity in high-density digital systems such as network switches and smartphone baseband subsystems.
For engineers reviewing the SN74ACT240N datasheet, SN74ACT240N pinout, SN74ACT240N application, or SN74ACT240N equivalent, key selection criteria include its dual 4-bit inverting architecture with independent output-enable controls, PDIP-20 package compatibility with through-hole prototyping and legacy industrial PCBs, and guaranteed operation across –40°C to +85°C ambient temperature range.
Technical Context
The SN74ACT240N implements two independent 4-bit inverting buffer sections (1A→1Y and 2A→2Y), each controlled by dedicated active-low output-enable inputs (1OE and 2OE). Its balanced CMOS push-pull outputs provide symmetrical sourcing and sinking capability (±24 mA), ensuring consistent rise/fall times and reduced signal distortion on shared buses.
Each section functions as a true inverter: when OE is low, Y = NOT(A); when OE is high, Y enters high-impedance state. Input voltage tolerance extends to 5.5 V regardless of VCC, supporting mixed-voltage interfacing without level shifters - critical for legacy 5 V logic integration with newer peripherals.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.5 V to 5.5 V - ensures stable operation across standard 5 V supply tolerances and brown-out conditions. |
| Max tPD | 8.5 ns at 5 V - enables reliable timing in high-speed address/data buses up to ~115 MHz toggle rate. |
| IOL / IOH | ±24 mA - sufficient to drive multiple TTL loads or terminate short stubs on parallel buses without external buffers. |
| Input Voltage Range | –0.5 V to VCC+0.5 V - allows safe interfacing with 5 V-tolerant I/O even during power sequencing mismatches. |
| Operating Temp | –40°C to +85°C - qualified for commercial and industrial environments including network infrastructure and handheld electronics. |
| Logic Function | Inverting 3-state buffer (dual 4-bit) - provides bidirectional bus control with isolated enable per group for flexible data routing. |
Pinout & Package
SN74ACT240N uses a 20-pin Plastic Dual In-line Package (PDIP-N), measuring 24.33 mm × 9.4 mm overall with a body size of 24.33 mm × 6.35 mm. The package features through-hole mounting, standard 0.1-inch pin pitch, and no thermal pad.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1OE, 19 | Active-low output enable (Group 1) | Controls Y1–Y4 outputs: low enables inversion (Y = NOT A), high places outputs in high-Z. |
| 2OE, 19 | Active-low output enable (Group 2) | Controls Y1–Y4 outputs: low enables inversion (Y = NOT A), high places outputs in high-Z. |
| 1A1–1A4, 2–4, 6, 8 | Group 1 input signals | Inverted and driven to corresponding Y1–Y4 outputs when 1OE is low. |
| 2A1–2A4, 11, 13, 15, 17 | Group 2 input signals | Inverted and driven to corresponding Y1–Y4 outputs when 2OE is low. |
| 1Y1–1Y4, 18, 16, 14, 12 | Group 1 inverted outputs | Driven low/high or placed in high-impedance based on 1A and 1OE states. |
| 2Y1–2Y4, 9, 5, 3, 7 | Group 2 inverted outputs | Driven low/high or placed in high-impedance based on 2A and 2OE states. |
| VCC, 20 | Positive supply | Must be decoupled locally; powers all internal logic and output drivers. |
| GND, 10 | Ground reference | Return path for all input/output currents; requires low-inductance connection to minimize noise. |
Key Features
| Feature | Design Value |
|---|---|
| TTL-compatible inputs | Accepts standard 0 V/5 V logic levels without external biasing - simplifies interface with legacy microcontrollers and FPGAs. |
| Independent 3-state control | Dual OE pins allow selective isolation of either 4-bit group, enabling time-multiplexed bus sharing without contention. |
| High drive strength | ±24 mA output current supports fan-out to ≥10 LS-TTL loads or direct termination of unterminated traces up to 10 cm. |
| Fast switching performance | 8.5 ns max tPD at 5 V ensures setup/hold margin preservation in 20–25 MHz synchronous bus designs. |
| Wide input voltage tolerance | Inputs withstand up to 5.5 V regardless of VCC - eliminates need for external clamping diodes in mixed-supply systems. |
Applications
| Memory Address Buffering | Industrial Bus Transceiver |
|---|---|
|
Use Scenario: Driving multiplexed address lines between microcontroller and SRAM/Flash in embedded controllers. IC Role / Device Role / Timing Role: Inverting 3-state buffer isolating CPU address bus from memory during read/write cycles. Use Value: Prevents bus contention during memory access arbitration while maintaining sub-10 ns timing margins for 20 MHz bus clocks. |
Use Scenario: Level-shifting and buffering between 5 V PLC I/O modules and fieldbus controller ASICs. IC Role / Device Role / Timing Role: Bidirectional data conditioning element on RS-485 or CAN physical layer interface boards. Use Value: Enables hot-swappable module detection via OE-controlled high-Z state, reducing system reset events during maintenance. |
| Smartphone Baseband Interface | Network Switch Control Plane |
|
Use Scenario: Interfacing application processor GPIOs to PMIC and sensor hub in compact handset designs. IC Role / Device Role / Timing Role: Signal translator and load driver for power rail enable/control signals with strict voltage tolerance. Use Value: 5.5 V input tolerance accommodates transient overshoot on shared power rails, avoiding latch-up during battery insertion. |
Use Scenario: Managing configuration registers and status reporting across multi-chip switch fabric in enterprise Ethernet switches. IC Role / Device Role / Timing Role: Parallel bus repeater between management MCU and PHY register banks. Use Value: Dual-group OE control allows staggered register access, preventing simultaneous write collisions on shared control bus. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal inverting buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ACT240DW | SOIC-20 package; 12.8 mm × 10.3 mm footprint; surface-mount only; identical electrical specs. | Requires reflow assembly; better thermal performance (RθJA = 101.2°C/W vs. 69°C/W for N package). | Select for space-constrained PCBs where automated SMT is available and thermal headroom is limited. |
| SN74LS240N | Lower drive (±15 mA); slower (tPD ≈ 15 ns); TTL-input threshold; higher ICC (40 mA typical vs. 40 µA for ACT). | Suitable for legacy 5 V systems with marginal timing budgets and no 5.5 V input tolerance requirement. | Choose only when backward compatibility with LS-family logic is mandatory and speed/power trade-offs are acceptable. |
Compared with SN74ACT240DW and SN74LS240N, the SN74ACT240N offers through-hole manufacturability with superior speed and input voltage margin, making it optimal for prototyping, repair, and industrial control boards where mechanical robustness and mixed-voltage resilience are prioritized over board area.
Availability
SN74ACT240N is available at Aetrix Electronics and suitable for industrial control panels, telecom infrastructure spares, and medical device service kits requiring stable component supply across extended product lifecycles.
Supply support for SN74ACT240N 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 innovation in high-reliability digital interfaces.
The SNx4ACT240 family was engineered to replace older TTL buffers in high-speed, low-power 5 V systems - delivering ACT-series performance with enhanced noise immunity and bus-driving capability for memory, clock, and control-plane applications.
FAQ
What is the function of the SN74ACT240N?
The SN74ACT240N is an octal inverting 3-state buffer with two independent 4-bit sections, each controlled by its own active-low output-enable input. When enabled, it inverts input signals (A → NOT Y); when disabled, outputs enter high-impedance state. This architecture supports bidirectional bus management and memory address driving in 5 V digital systems.
Does the SN74ACT240N support 5 V tolerant inputs?
Yes, the SN74ACT240N accepts input voltages up to 5.5 V regardless of VCC level - a key feature that enables safe interfacing with 5 V logic in mixed-supply environments and eliminates need for external clamping diodes during power-up sequencing or signal overshoot events.
What is the maximum propagation delay for SN74ACT240N at 5 V?
The maximum propagation delay (tPD) for SN74ACT240N is 8.5 ns at VCC = 5 V and TA = 25°C. This value applies to both rising and falling edges under standard test conditions (CL = 50 pF), supporting reliable operation in synchronous bus designs up to approximately 20 MHz.
Can SN74ACT240N drive multiple TTL loads directly?
Yes, the SN74ACT240N can drive up to 10 LS-TTL loads per output due to its ±24 mA drive strength. Each output maintains valid logic levels across this fan-out while staying within absolute maximum ratings, eliminating need for additional buffer stages in most 5 V bus applications.
Is SN74ACT240N compatible with through-hole PCB assembly?
Yes, the SN74ACT240N uses a 20-pin PDIP (N) package with 0.1-inch pin spacing and standard through-hole footprint. It supports wave soldering, hand soldering, and socket-based prototyping - making it ideal for legacy industrial designs, lab validation, and field-service replacement scenarios.
SN74ACT240N Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ACT
- Package/Case:
- 20-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- 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:
- 24mA, 24mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 20-PDIP
SN74ACT240N FAQ
1.How can I place an order for SN74ACT240N through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ACT240N 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 SN74ACT240N reliable?
The price and inventory of SN74ACT240N are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ACT240N is usually 5 days.
3.What payment methods are accepted for SN74ACT240N?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74ACT240N transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74ACT240N?
SN74ACT240N orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ACT240N 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 SN74ACT240N?
For technical support, including SN74ACT240N datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ACT240N requirements.
6.How does Aetrix verify that SN74ACT240N is sourced from the original manufacturer or authorized distributors?
All SN74ACT240N 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 SN74ACT240N meets industry standards.
7.What is the process for return or replacement of SN74ACT240N?
All SN74ACT240N units undergo pre-shipment inspection (PSI). If there is an issue with SN74ACT240N, 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 SN74ACT240N part is unused and in its original packaging.
Return procedure for SN74ACT240N:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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