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Texas Instruments SN74ACT240NSR
- Part No.:
- SN74ACT240NSR
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
SN74ACT240NSR.pdf
- Description:
- IC BUFF INVERT 5.5V 20SO
- Quantity:
- Payment:
- Shipping:
Inventory:6,119
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Product details
Overview
SN74ACT240NSR from Texas Instruments is an octal 3-state inverting buffer/driver IC designed for bus-oriented data transmission, clock distribution, and memory address driving in industrial and consumer systems. 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 features balanced CMOS push-pull outputs capable of ±24 mA drive per channel - enabling robust signal integrity in high-density PCB layouts.
For engineers reviewing the SN74ACT240NSR datasheet, SN74ACT240NSR pinout, SN74ACT240NSR application, or SN74ACT240NSR equivalent, this page provides verified functional specifications, SOP-20 package details, real-world use cases in network switches and wearables, and two validated alternative parts with documented technical and application differences.
Technical Context
The SN74ACT240NSR implements two independent 4-bit inverting buffer sections, each controlled by a dedicated output-enable (OE) input. Its logic function is strictly inverting: when OE is low, A→Y inversion occurs; when OE is high, all eight Y outputs enter high-impedance state. This dual-OE architecture enables bidirectional bus control without external logic.
It uses advanced ACT (Advanced CMOS TTL-compatible) process technology, delivering rail-to-rail output swing, fast edge rates, and immunity to input overvoltage beyond VCC. The device meets JEDEC JESD78 Class II latch-up immunity and supports operation from –40°C to +85°C - confirmed for the NS package variant per TI's official orderable data.
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 ripple without functional degradation. |
| Max Propagation Delay | 8.5 ns at 5 V - enables reliable timing in high-speed address/data buses up to ~100 MHz system clock domains. |
| Output Drive | ±24 mA per channel - sufficient to drive 50 Ω transmission lines or fan-out to ≥10 standard TTL loads. |
| Input Voltage Range | 0 V to VCC + 0.5 V - allows safe interfacing with 5 V-tolerant microcontrollers even during hot-swap or power sequencing events. |
| Logic Function | Inverting 3-state buffer (A→Y inversion, OE-controlled high-Z) - supports bidirectional bus arbitration and memory address isolation. |
| Operating Temperature | –40°C to +85°C - qualified for industrial-grade embedded applications including network infrastructure and wearable electronics. |
| Power Dissipation Cap. | 45 pF per buffer - defines dynamic power consumption under 1 MHz switching with 50 pF load; critical for thermal budgeting in dense layouts. |
Pinout & Package
SOP-20 (NS) package: 12.6 mm × 7.8 mm body size, 12.6 mm × 5.3 mm footprint excluding leads, 1.75 mm nominal height, gull-wing leads, RoHS-compliant NiPdAu lead finish, MSL Level-1 (260°C peak reflow).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1OE | Input | Active-low enable for first 4-bit buffer section (controls Y1–Y4); tie high via pullup for power-up high-Z safety. |
| 1A1–1A4 | Inputs | Inverting data inputs for first section; accept TTL/CMOS logic levels; internally terminated to avoid floating states. |
| 1Y1–1Y4 | Outputs | Inverted buffered outputs (1A→1Y); high-Z when 1OE = high; ±24 mA sink/source capability. |
| 2OE | Input | Active-low enable for second 4-bit buffer section (controls Y1–Y4 of second group); independent of 1OE. |
| 2A1–2A4 | Inputs | Inverting data inputs for second section; electrically identical to 1Ax; supports separate bus domain control. |
| 2Y1–2Y4 | Outputs | Inverted buffered outputs (2A→2Y); fully isolated from first section; same drive strength and timing as 1Yx. |
| VCC | Power | 5 V supply pin (Pin 20); requires local 0.1 µF ceramic decoupling adjacent to pin for noise suppression. |
| GND | Ground | Reference return (Pin 10); must be connected to low-impedance system ground plane to maintain signal integrity. |
Key Features
| Feature | Design Value |
|---|---|
| Inverting 3-state logic | Enables bidirectional bus sharing and prevents contention in multi-master systems without external direction control logic. |
| TTL-compatible inputs | Accepts standard 0.8 V / 2.0 V logic thresholds - eliminates level-shifting when interfacing with legacy 5 V microcontrollers or FPGAs. |
| Balanced CMOS outputs | Sinks and sources equal current (±24 mA), ensuring symmetrical rise/fall times and minimizing ground bounce in shared return paths. |
| Overvoltage-tolerant inputs | Withstands up to VCC + 0.5 V - protects against I/O glitches during hot-plug or mixed-voltage board bring-up. |
| Low propagation delay | 8.5 ns max at 5 V - supports timing-critical applications such as memory address latching and synchronous clock fanout. |
Applications
| Network Switch Data Path | Smartphone Baseband Interface |
|---|---|
Use Scenario: Isolating and buffering address/data lines between ASIC and external SRAM or flash in Layer 2/Layer 3 switch control plane. IC Role / Device Role / Timing Role: Octal inverting buffer providing level-shifted, slew-controlled signals with independent OE control per 4-bit segment. Use Value: Prevents bus contention during firmware updates and enables clean power-down sequencing without latch-up risk. |
Use Scenario: Interfacing application processor GPIOs to sensor hub or PMIC registers in compact smartphone mainboard layout. IC Role / Device Role / Timing Role: Signal conditioner and bus isolator for low-latency sensor data acquisition and configuration writes. Use Value: Delivers <8.5 ns delay and ±24 mA drive within tight 12.6 mm × 7.8 mm SOP footprint - conserving board area in space-constrained designs. |
| Wearable Health Monitor Bus | Industrial PLC I/O Module |
Use Scenario: Driving multiple analog front-end (AFE) configuration lines and status indicators in wrist-worn ECG/PPG modules. IC Role / Device Role / Timing Role: Low-power 3-state buffer enabling dynamic reconfiguration of sensor channels while maintaining signal fidelity. Use Value: Operates reliably across –40°C to +85°C ambient and consumes only 40 µA typical ICC - extending battery life. |
Use Scenario: Buffering digital I/O expansion signals between main controller and isolated field-side peripherals in DIN-rail mounted PLCs. IC Role / Device Role / Timing Role: Robust interface IC with overvoltage-tolerant inputs protecting against induced transients on long cable runs. Use Value: Withstands 5.5 V input surges and maintains 3-state isolation during brownout conditions - improving system fault resilience. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal 3-state inverting buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ACT240DWR | SOIC-20 package (12.8 mm × 10.3 mm), higher RθJA (101.2°C/W), same electrical specs and pinout. | Preferred for through-hole prototyping or legacy board reuse where larger footprint is acceptable. | Select DWR if board layout accommodates SOIC dimensions and thermal margin exceeds 101.2°C/W requirement. |
| SN74ACT240DGSR | VSSOP-20 package (5.1 mm × 4.9 mm), lower thermal resistance (123.5°C/W), identical logic and timing behavior. | Optimized for ultra-compact portable electronics requiring minimal PCB area and fine-pitch assembly. | Choose DGSR when space constraints demand sub-6 mm × 5 mm footprint and reflow profile supports MSL-1 handling. |
Compared with SN74ACT240NSR, the DWR offers greater thermal mass but occupies 3× more board area, while DGSR reduces footprint by 68% yet requires tighter thermal design due to higher junction-to-ambient resistance - making NS the balanced choice for cost-sensitive industrial designs needing SOP compatibility and moderate density.
Availability
SN74ACT240NSR is available at Aetrix Electronics and suitable for industrial PLC I/O modules, network switch control planes, and wearable health monitor buses requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for SN74ACT240NSR 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 connectivity technologies, with over 90 years of innovation in high-reliability electronic components.
The SN74ACT240NSR belongs to TI's legacy 74ACT logic family, engineered for high-speed, low-noise 5 V digital interfacing in industrial, communications, and consumer equipment - emphasizing robustness, timing precision, and wide operating margins.
FAQ
What is the maximum output current rating for SN74ACT240NSR?
The SN74ACT240NSR is rated for ±24 mA per output channel under recommended operating conditions (VCC = 4.5 V to 5.5 V, TA = –40°C to +85°C). This value is specified in the Electrical Characteristics table for both IOH and IOL, and represents the guaranteed sink/source capability before voltage compliance degrades beyond VOH ≥ 3.7 V or VOL ≤ 0.5 V. Exceeding this current risks thermal overstress or parametric shift.
Does SN74ACT240NSR support non-inverting operation?
No, the SN74ACT240NSR implements fixed inverting logic only: each A input drives its corresponding Y output with inversion (A→Y = NOT A). There is no internal configuration or external pin to disable inversion. For non-inverting 3-state buffers, TI recommends the SN74ACT244NSR - a functionally complementary part in the same SOP-20 package with identical timing and drive specs.
What is the recommended decoupling for SN74ACT240NSR?
TI specifies a minimum 0.1 µF ceramic capacitor placed as close as possible to the VCC (Pin 20) and GND (Pin 10) pins of the SN74ACT240NSR. This capacitor must have low ESL/ESR and be mounted directly on the top layer with short, wide traces to the pads. For boards with multiple SN74ACT240NSR devices, one 0.1 µF cap per device is required; bulk capacitance (e.g., 4.7 µF tantalum) should be added at the board-level power entry point.
Is SN74ACT240NSR pin-compatible with other 74ACT240 variants?
Yes, the SN74ACT240NSR shares identical pinout and logic functionality with all industry-standard 74ACT240 variants in 20-pin packages (including SOIC, SSOP, TSSOP, PDIP, and VQFN). Pin numbering, signal names (1OE, 1A1–1A4, 1Y1–1Y4, 2OE, 2A1–2A4, 2Y1–2Y4, VCC, GND), and electrical behavior are fully consistent across TI's 74ACT240 family - enabling direct substitution where package mounting permits.
What does the 'NS' in SN74ACT240NSR signify?
The 'NS' in SN74ACT240NSR denotes the SOP (Small Outline Package) variant with 20 pins, per TI's standardized package coding. It is distinct from 'DWR' (SOIC), 'DGSR' (VSSOP), 'DBR' (SSOP), and 'RKSR' (VQFN). The 'R' suffix indicates tape-and-reel packaging (2000 units per reel), and the absence of '-Q1' confirms it is the commercial-grade catalog version - not automotive-qualified.
SN74ACT240NSR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ACT
- Package/Case:
- 20-SOIC (0.209", 5.30mm Width)
- Packaging:
- Tape & Reel (TR)
- 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:
- Surface Mount
- Supplier Device Package:
- 20-SO
SN74ACT240NSR FAQ
1.How can I place an order for SN74ACT240NSR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ACT240NSR 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 SN74ACT240NSR reliable?
The price and inventory of SN74ACT240NSR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ACT240NSR is usually 5 days.
3.What payment methods are accepted for SN74ACT240NSR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74ACT240NSR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74ACT240NSR?
SN74ACT240NSR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ACT240NSR 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 SN74ACT240NSR?
For technical support, including SN74ACT240NSR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ACT240NSR requirements.
6.How does Aetrix verify that SN74ACT240NSR is sourced from the original manufacturer or authorized distributors?
All SN74ACT240NSR 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 SN74ACT240NSR meets industry standards.
7.What is the process for return or replacement of SN74ACT240NSR?
All SN74ACT240NSR units undergo pre-shipment inspection (PSI). If there is an issue with SN74ACT240NSR, 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 SN74ACT240NSR part is unused and in its original packaging.
Return procedure for SN74ACT240NSR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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