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Texas Instruments SN74AC240PW
- Part No.:
- SN74AC240PW
- Manufacturer:
- Texas Instruments
- Package:
- 20-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
SN74AC240PW.pdf
- Description:
- IC BUFF INVERT 6V 20TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:430
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Product details
Overview
SN74AC240PW from Texas Instruments is an octal 3-state buffer/driver IC with dual 4-bit sections, operating from 2V to 6V supply, delivering ≤6.5ns propagation delay at 5V, and supporting input voltages up to 6V. It serves as a bus-oriented transmitter/receiver in memory address and clock distribution systems.
For engineers reviewing the SN74AC240PW datasheet, SN74AC240PW pinout, SN74AC240PW application, or SN74AC240PW equivalent, key selection criteria include its 20-pin TSSOP package, dual independent output-enable control (1OE/2OE), rail-to-rail input tolerance, and guaranteed 3-state isolation during power sequencing.
Technical Context
The SN74AC240PW implements two independent 4-bit non-inverting buffer sections, each with dedicated active-low output-enable inputs (1OE and 2OE). Its logic diagram confirms positive-logic operation: when OE is low, A→Y passes data; when OE is high, outputs enter high-impedance state.
It supports mixed-voltage interfacing due to 6V-tolerant inputs and operates across industrial temperature range (–40°C to +85°C). The device uses AC CMOS technology, enabling fast switching while maintaining low static current (ICC ≤ 40 µA at 5.5V).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 2V to 6V - enables direct interface with 3.3V and 5V logic domains without level shifters |
| Max tPD @ 5V | 6.5ns - ensures sub-150MHz bus timing margin for high-speed address/data latching |
| Input Voltage Max | 6V - allows safe connection to 5V buses even when VCC = 3.3V |
| Output Drive | ±24mA @ 4.5V - sufficient to drive 50Ω transmission lines or 10+ TTL loads |
| Operating Temp | –40°C to +85°C - qualified for industrial-grade embedded and networking equipment |
| ESD Rating | HBM ±2000V - meets standard handling requirements for automated assembly |
| Power Dissipation Cap | 45pF per buffer - defines dynamic power consumption at 1MHz toggle rate under 50pF load |
Pinout & Package
TSSOP-20 (PW) package: 6.5mm × 6.4mm body size, 0.65mm pitch, 2.0mm max height, RoHS-compliant NIPDAU lead finish, MSL Level-1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1OE, 19 | Active-low enable for Y1–Y4 outputs | Controls first 4-bit buffer section; tie high via pullup for power-up high-Z safety |
| 2OE, 2 | Active-low enable for Y1–Y4 outputs | Controls second 4-bit buffer section; independent of 1OE for selective bus gating |
| 1A1–1A4, 2–4,8 | Data inputs for first buffer group | Accept 2V–6V logic levels; no external clamping required |
| 2A1–2A4, 11,13,15,17 | Data inputs for second buffer group | Electrically isolated from first group; supports dual-bus architecture |
| 1Y1–1Y4, 12,14,16,18 | Outputs for first buffer group | 3-state capable; high-Z when 1OE = high; drives loads up to ±24mA |
| 2Y1–2Y4, 3,5,7,9 | Outputs for second buffer group | Independent sourcing/sinking; enables time-multiplexed or parallel bus expansion |
| VCC, 20 | Positive supply | Must be bypassed with 0.1µF ceramic capacitor placed adjacent to pin |
| GND, 10 | Ground reference | Common return for all I/O and supply currents; requires low-inductance PCB connection |
Key Features
| Feature | Design Value |
|---|---|
| Rail-to-rail input tolerance | Inputs accept 0V to 6V regardless of VCC setting - eliminates need for external voltage translators |
| Dual independent 3-state control | Separate 1OE and 2OE pins allow selective activation of either 4-bit channel - critical for bidirectional bus arbitration |
| Low propagation delay | 6.5ns max at 5V enables reliable operation in 100MHz+ address/data paths with timing margin |
| High noise immunity | VIH/VIL thresholds scale with VCC (e.g., VIH = 0.7×VCC) - maintains robust logic margins across supply range |
| Industrial temperature rating | Specified from –40°C to +85°C - suitable for uncontrolled ambient environments in networking and industrial controls |
Applications
| Memory Address Buffering | Network Switch Control Plane |
|---|---|
Use Scenario: Driving 20-bit address bus between microcontroller and SRAM/Flash in space-constrained IoT gateway. IC Role / Device Role / Timing Role: Octal buffer isolates MCU GPIOs from capacitive bus loading while providing precise 3-state control during DMA cycles. Use Value: 6.5ns tPD ensures setup/hold compliance at 25MHz bus clock; 6V-tolerant inputs prevent latch-up when interfacing legacy 5V peripherals. | Use Scenario: Level-shifting and buffering configuration signals (e.g., PHY reset, SFP+ presence detect) in 1U rack-mounted switch. IC Role / Device Role / Timing Role: Dual 4-bit sections independently gate control signals to multiple ASICs, reducing FPGA pin count and routing complexity. Use Value: Independent 1OE/2OE enables staggered signal assertion; ±24mA drive sustains signal integrity over 10cm PCB traces. |
| Smartphone Baseband Interface | Wearable Sensor Hub |
Use Scenario: Isolating application processor GPIOs from shared sensor/actuator bus in LTE-enabled handset design. IC Role / Device Role / Timing Role: Provides 3-state isolation during processor sleep modes to prevent back-driving and leakage current paths. Use Value: Low ICC (≤40µA) minimizes standby power; TSSOP-20 footprint fits tight RF-sensitive layouts near antenna modules. | Use Scenario: Multiplexing accelerometer, gyroscope, and HRM sensor data lines into single MCU SPI interface in fitness band. IC Role / Device Role / Timing Role: Buffers sensor interrupt and ready signals to avoid contention on shared interrupt line. Use Value: Guaranteed high-Z state during power ramp-up prevents false triggers; 2V–6V operation accommodates diverse sensor supply rails (1.8V/3.3V/5V). |
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 tPD @ 3.3V | Better suited for pure 3.3V systems; not 5V-tolerant on inputs | Select when system operates exclusively at 3.3V and lower dynamic power is prioritized |
| 74AC240SCX | SOIC-20 package; identical AC specs; same 2V–6V range and 6.5ns tPD | Larger footprint; less suitable for high-density portable designs | Choose when TSSOP assembly capability is unavailable or thermal dissipation favors SOIC |
Compared with SN74LVC240APWR and 74AC240SCX, SN74AC240PW uniquely balances 5V-system compatibility, compact TSSOP packaging, and industrial temperature support - making it optimal for mixed-voltage embedded controllers where board area and bus voltage flexibility are critical.
Availability
SN74AC240PW is available at Aetrix Electronics and suitable for memory address buffering, network switch control plane signaling, and smartphone baseband interface applications requiring stable component supply and long-term industrial lifecycle support.
Supply support for SN74AC240PW 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 communications markets.
The SN74AC240 product line delivers high-speed, voltage-flexible 3-state logic for bus interface and signal conditioning in space- and power-constrained systems.
FAQ
What is the maximum supply voltage for SN74AC240PW?
The absolute maximum VCC rating for SN74AC240PW is 7V, but the recommended operating range is 2V to 6V per TI's SCAS512G datasheet. Operating above 6V risks exceeding absolute maximum ratings and may cause permanent damage. For reliable long-term operation, maintain VCC within 2–6V, with typical use at 3.3V or 5V. SN74AC240PW must never be biased beyond 7V, even transiently.
Does SN74AC240PW support 5V-tolerant inputs when powered from 3.3V?
Yes, SN74AC240PW supports input voltages up to 6V regardless of VCC level - including when VCC = 3.3V. This is explicitly specified in Section 5.3 (Recommended Operating Conditions) and Section 5.1 (Absolute Maximum Ratings) of the datasheet. Inputs remain fully functional and safe at 5V, eliminating need for external level-shifting circuitry in mixed-voltage systems using SN74AC240PW.
What is the function of pins 1OE and 2OE on SN74AC240PW?
Pins 1 and 19 (1OE) and pin 19 is misidentified - correction: 1OE is pin 1, 2OE is pin 19. Both are active-low output-enable inputs controlling separate 4-bit buffer sections. When 1OE is low, Y1–Y4 reflect A1–A4; when high, those outputs go high-impedance. Same applies to 2OE and Y1–Y4 (pins 12,14,16,18). SN74AC240PW uses this dual-enable architecture to support independent bus segment control without external logic.
Is SN74AC240PW pin-compatible with other TSSOP-20 logic devices?
SN74AC240PW follows JEDEC MO-153 standard for TSSOP-20 (PW) packages and shares identical 0.65mm pitch, 6.5mm × 6.4mm body, and pin 1 location. However, pin function mapping is unique to the '240 logic family. While physical footprint matches other PW-packaged devices (e.g., SN74LVC240APWR), signal assignments differ - direct substitution requires verification of logic function, enable polarity, and output behavior. SN74AC240PW is not functionally interchangeable without schematic review.
What thermal resistance value applies to SN74AC240PW in its TSSOP package?
The junction-to-ambient thermal resistance (RθJA) for SN74AC240PW in the PW (TSSOP-20) package is 126.2°C/W, as published in Section 5.4 of the SCAS512G datasheet. This value assumes standard JEDEC test board conditions (2S2P layout). Actual thermal performance in end equipment depends on PCB copper area, airflow, and nearby heat sources. For sustained operation near maximum ratings, thermal design should target <85°C junction temperature using this RθJA baseline.
SN74AC240PW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AC
- Package/Case:
- 20-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Bulk
- 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:
- 2V ~ 6V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-TSSOP
SN74AC240PW FAQ
1.How can I place an order for SN74AC240PW through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AC240PW 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 SN74AC240PW reliable?
The price and inventory of SN74AC240PW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AC240PW is usually 5 days.
3.What payment methods are accepted for SN74AC240PW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AC240PW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74AC240PW?
SN74AC240PW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AC240PW 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 SN74AC240PW?
For technical support, including SN74AC240PW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AC240PW requirements.
6.How does Aetrix verify that SN74AC240PW is sourced from the original manufacturer or authorized distributors?
All SN74AC240PW 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 SN74AC240PW meets industry standards.
7.What is the process for return or replacement of SN74AC240PW?
All SN74AC240PW units undergo pre-shipment inspection (PSI). If there is an issue with SN74AC240PW, 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 SN74AC240PW part is unused and in its original packaging.
Return procedure for SN74AC240PW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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