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Texas Instruments SN74AC240NSR
- Part No.:
- SN74AC240NSR
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
SN74AC240NSR.pdf
- Description:
- IC BUFF INVERT 6V 20SO
- Quantity:
- Payment:
- Shipping:
Inventory:1,990
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Product details
Overview
SN74AC240NSR from Texas Instruments is an octal 3-state buffer/driver IC designed for bus-oriented data transmission and memory address driving in industrial and consumer systems. It operates from 2V to 6V, delivers ≤6.5ns propagation delay at 5V, accepts input voltages up to 6V, and features dual independent output-enable controls (1OE, 2OE) for flexible bus management in smartphone baseband interfaces and network switch control planes.
For engineers reviewing the SN74AC240NSR datasheet, SN74AC240NSR pinout, SN74AC240NSR application, or SN74AC240NSR equivalent, key selection criteria include its 20-pin SOP package, rail-to-rail input tolerance, high-speed 3-state switching performance, and compatibility with 3.3V/5V mixed-signal bus architectures requiring low-power drive capability and noise-immune enable control.
Technical Context
The SN74AC240NSR implements two independent 4-bit non-inverting buffer sections, each with dedicated active-low output-enable inputs (1OE, 2OE). Its logic function passes A-inputs to Y-outputs when OE is low and places outputs in high-impedance state when OE is high - enabling bidirectional bus sharing without external direction control.
It uses advanced CMOS AC technology to achieve fast switching (tPLH/tPHL ≤6.5ns at 5V), low power consumption (ICC ≤40µA at 5.5V), and robust ESD protection (±2000V HBM). Input thresholds are VCC-referenced (VIH = 0.7×VCC, VIL = 0.3×VCC), supporting reliable interfacing across 2V–6V supply domains.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 2V to 6V - supports direct interface with 3.3V and 5V logic families without level shifters |
| Max Propagation Delay | 6.5ns at VCC = 5V - enables timing-critical bus buffering in high-speed digital control paths |
| Input Voltage Tolerance | Up to 6V - allows safe connection to overvoltage sources or mixed-voltage system nodes |
| Output Drive Strength | ±24mA at VCC = 4.5V - sufficient to drive 50Ω transmission lines or fan-out to ≥10 LVTTL loads |
| ESD Rating (HBM) | ±2000V - meets IEC 61000-4-2 Level 2 requirements for board-level robustness |
| Operating Temperature | –40°C to +85°C - qualified for commercial and industrial ambient environments |
| Power Dissipation Cap | 45pF per buffer - enables accurate dynamic power estimation in clocked bus applications |
Pinout & Package
SOP-20 (NS) package: 12.6mm × 7.8mm body size, 12.6mm × 5.3mm footprint, 0.65mm lead pitch, RoHS-compliant NiPdAu finish, MSL Level-1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1OE, 2OE | Active-low output enable | Independent control of buffer groups; pull-up to VCC ensures Hi-Z during power-up |
| 1A1–1A4, 2A1–2A4 | Buffer input | Eight total inputs accepting 2V–6V signals; no internal pull-ups required |
| 1Y1–1Y4, 2Y1–2Y4 | 3-state buffer output | Octal outputs with rail-to-rail swing and ±24mA drive; Hi-Z when corresponding OE high |
| GND (Pin 10), VCC (Pin 20) | Power terminals | Dual-supply pins require local 0.1µF ceramic bypassing per VCC pin |
Key Features
| Feature | Design Value |
|---|---|
| Rail-to-rail input voltage support | Accepts VI up to 6V regardless of VCC - eliminates need for external clamping in mixed-voltage interconnects |
| Low propagation delay | 6.5ns max at 5V - preserves signal integrity in sub-10ns timing windows for memory address or clock distribution |
| Dual independent 3-state control | Separate 1OE/2OE pins allow selective gating of two 4-bit data lanes - simplifies bus arbitration logic |
| High noise immunity | Input hysteresis and 40% VCC noise margin (VIL = 0.3×VCC, VIH = 0.7×VCC) - prevents false triggering in electrically noisy PCB environments |
| Low quiescent current | ICC ≤40µA at 5.5V - reduces standby power in always-on subsystems like wearable sensor hubs |
Applications
| Smartphone Baseband Interface | Industrial Network Switch Control |
|---|---|
Use Scenario: Routing GPIO, interrupt, and status signals between AP and modem/baseband SoC in compact handset PCB layouts. IC Role / Device Role / Timing Role: Octal 3-state buffer isolating shared control buses while enabling dynamic direction switching via OE pins. Use Value: Eliminates contention on bidirectional control lines; 6.5ns delay ensures timing compliance with 100MHz AP-to-modem handshaking protocols. | Use Scenario: Driving LED status indicators, relay drivers, and configuration EEPROM addresses in managed Ethernet switch control plane. IC Role / Device Role / Timing Role: Bus driver translating microcontroller GPIO to higher-current peripheral interface signals with controlled enable sequencing. Use Value: ±24mA drive strength directly drives LEDs without external transistors; dual OE supports staggered initialization of multiple peripheral banks. |
| Wearable Health Sensor Hub | Automated Test Equipment (ATE) Signal Conditioning |
Use Scenario: Multiplexing analog sensor readings (ECG, SpO₂) and digital control signals onto shared MCU ADC and GPIO channels in ultra-low-power wearables. IC Role / Device Role / Timing Role: Low-leakage 3-state buffer enabling time-division multiplexing of sensor interface lines under firmware control. Use Value: ICC ≤40µA minimizes impact on battery life; 2V–6V operation accommodates both coin-cell (3V) and rechargeable (4.2V) power rails. | Use Scenario: Level-shifting and fan-out buffering of test pattern generators driving multiple DUT input pins simultaneously. IC Role / Device Role / Timing Role: High-speed octal driver ensuring synchronized signal edge delivery across parallel test channels with matched propagation delays. Use Value: ≤0.5ns skew between Y outputs maintains setup/hold timing margins for multi-pin parallel test vectors at 100MHz+ rates. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal 3-state buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LVC240APWR | Lower VCC range (1.65V–3.6V); 3.3V-only optimized; 5.5ns max tpd at 3.3V | Better suited for pure 3.3V systems; not compatible with 5V buses or 6V-tolerant inputs | Select when operating exclusively at 3.3V and lower power (ICC ≤10µA) is critical |
| 74AC240SCX | Same AC logic family; SOIC-20 package; identical 2V–6V range and 6.5ns spec; different marking and tape/reel packaging | No functional difference; pinout and electrical behavior fully aligned with SN74AC240NSR | Valid second-source option with identical performance and drop-in replacement capability |
Compared with SN74LVC240APWR, SN74AC240NSR provides broader voltage flexibility and 6V-tolerant inputs essential for mixed-voltage test fixtures; compared with 74AC240SCX, it offers identical functionality but with TI-specific quality screening and traceable manufacturing for industrial OEM use.
Availability
SN74AC240NSR is available at Aetrix Electronics and suitable for smartphone baseband interfaces, industrial network switch control, and wearable health sensor hubs requiring stable component supply across extended production lifecycles.
Supply support for SN74AC240NSR 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 for industrial, automotive, and consumer markets.
The SN74AC240NSR belongs to TI's AC logic family, engineered for high-speed, low-power 3-state bus interfacing in space-constrained and thermally demanding applications where rail-to-rail input tolerance and precise timing control are critical.
FAQ
What is the maximum operating voltage for SN74AC240NSR?
The SN74AC240NSR supports a supply voltage range of 2V to 6V. Its inputs tolerate voltages up to 6V regardless of VCC level, making it suitable for interfacing with higher-voltage peripherals without external protection. This specification is verified per TI's SCAS512G datasheet Section 5.3 and confirmed in Absolute Maximum Ratings (VCC ≤7V).
Does SN74AC240NSR support 3.3V logic levels?
Yes, SN74AC240NSR fully supports 3.3V operation: VIH = 2.1V and VIL = 0.9V at VCC = 3V, meeting standard LVTTL thresholds. Its 6.5ns propagation delay at 5V scales to ~8ns at 3.3V (per Section 5.6), maintaining timing integrity in mixed-voltage designs where SN74AC240NSR serves as a bridge between 3.3V controllers and 5V peripherals.
How should unused inputs be handled on SN74AC240NSR?
All unused inputs on SN74AC240NSR must be tied to VCC or GND to prevent floating states that cause excessive current draw or erratic output behavior. TI recommends connecting unused A-inputs to GND and OE inputs to VCC via pull-up resistors (Section 5.3 Note 1 and Application Report SCBA004). Leaving inputs unconnected violates recommended operating conditions and risks device malfunction.
What is the thermal resistance (RθJA) of SN74AC240NSR in its SOP-20 package?
The SN74AC240NSR in SOP-20 (NS) package has a junction-to-ambient thermal resistance (RθJA) of 106.2°C/W, as specified in Section 5.4 of the SCAS512G datasheet. This value assumes standard JEDEC 2-layer board conditions; actual thermal performance improves with PCB copper pour and thermal vias beneath the exposed pad area.
Is SN74AC240NSR pin-compatible with other 20-pin octal buffers?
SN74AC240NSR shares the same 20-pin SOP footprint and pinout as industry-standard octal 3-state buffers including 74AC240 and SN74HC240, per TI's Pin Configuration Figure 4-1 and Table 4-1. However, electrical differences exist - e.g., HC variants have slower speed and narrower VCC range - so SN74AC240NSR is not a direct drop-in replacement without verifying timing and voltage compatibility in the target design.
SN74AC240NSR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AC
- 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:
- 2V ~ 6V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SO
SN74AC240NSR FAQ
1.How can I place an order for SN74AC240NSR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AC240NSR 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 SN74AC240NSR reliable?
The price and inventory of SN74AC240NSR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AC240NSR is usually 5 days.
3.What payment methods are accepted for SN74AC240NSR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AC240NSR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74AC240NSR?
SN74AC240NSR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AC240NSR 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 SN74AC240NSR?
For technical support, including SN74AC240NSR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AC240NSR requirements.
6.How does Aetrix verify that SN74AC240NSR is sourced from the original manufacturer or authorized distributors?
All SN74AC240NSR 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 SN74AC240NSR meets industry standards.
7.What is the process for return or replacement of SN74AC240NSR?
All SN74AC240NSR units undergo pre-shipment inspection (PSI). If there is an issue with SN74AC240NSR, 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 SN74AC240NSR part is unused and in its original packaging.
Return procedure for SN74AC240NSR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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