My Inquiry
My Account
Texas Instruments SN74AC240DW
- Part No.:
- SN74AC240DW
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74AC240DW.pdf
- Description:
- IC BUFF INVERT 6V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:855
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SN74AC240DW from Texas Instruments is an octal buffer/driver IC with dual 4-bit channels, 3-state outputs, 2V–6V supply operation, 6.5ns max propagation delay at 5V, and input tolerance up to 6V. It serves as a bus-oriented transceiver in memory address and clock distribution circuits for industrial control and communications infrastructure.
For engineers reviewing the SN74AC240DW datasheet, SN74AC240DW pinout, SN74AC240DW application, or SN74AC240DW equivalent, key selection criteria include VCC range compatibility (2–6V), 3-state output enable timing (tPZH/tPLZ ≤ 11ns at 5V), thermal resistance (RθJA = 101.2°C/W), and SOIC-20 package footprint constraints.
Technical Context
The SN74AC240DW implements two independent 4-bit noninverting buffers, each with dedicated active-low output-enable (1OE, 2OE) inputs controlling high-impedance states. Its AC logic family delivers rail-to-rail input voltage acceptance (up to 6V) while operating from 2V to 6V VCC, enabling mixed-voltage system interfacing.
Switching performance is characterized at both 3.3V ±0.3V and 5V ±0.5V supply conditions, with tPLH/tPHL ≤ 7ns and tPZH/tPLZ ≤ 11ns (max) at 5V. Output drive capability supports ±24mA at 4.5V–5.5V, and input leakage remains ≤±1µA across full temperature range (–40°C to +85°C).
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 Propagation Delay | 6.5ns at 5V - ensures sub-150MHz bus timing margin for address/data latching |
| Input Voltage Tolerance | Up to 6V - allows safe connection to higher-voltage control signals without clamping diodes |
| Output Drive Current | ±24mA at 4.5V–5.5V - sufficient to drive 50Ω transmission lines or 10+ CMOS loads |
| Operating Temperature | –40°C to +85°C - qualified for industrial ambient environments including network switch chassis |
| ESD Rating (HBM) | ±2000V - meets IEC 61000-4-2 Level 2 for board-level handling robustness |
| Power Dissipation Cap | 45pF per buffer - defines dynamic power consumption under 1MHz switching with 50pF load |
Pinout & Package
SN74AC240DW uses a 20-pin SOIC (DW) package with 12.8mm × 10.3mm body size, 1.27mm lead pitch, and 2.65mm maximum height. Pin 1 index is marked by a beveled corner or dot; leads are gull-wing, RoHS-compliant NiPdAu finish.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1OE | Active-low output enable (Channel 1) | Drives all Y1–Y4 outputs into high-Z when high; ties to VCC via pullup for power-up safety |
| 1A1–1A4 | Inputs (Channel 1) | Noninverting data inputs feeding Y1–Y4; accept 0–6V regardless of VCC |
| 2Y1–2Y4 | Outputs (Channel 2) | 3-state buffered outputs controlled by 2OE; sink/source ±24mA at 5V |
| 2A1–2A4 | Inputs (Channel 2) | Noninverting data inputs feeding 1Y1–1Y4; electrically identical to 1A1–1A4 |
| 1Y1–1Y4 | Outputs (Channel 1) | 3-state buffered outputs controlled by 1OE; match 2Y1–2Y4 in drive strength and timing |
| 2OE | Active-low output enable (Channel 2) | Independent control of 2Y1–2Y4; allows asymmetric channel enable/disable sequencing |
| GND (Pin 10) | Ground reference | Primary return path for all I/O and internal logic; requires low-inductance PCB connection |
| VCC (Pin 20) | Supply voltage | Single power rail for entire device; requires local 0.1µF ceramic bypass capacitor |
Key Features
| Feature | Design Value |
|---|---|
| Rail-to-rail input voltage support | Accepts VI up to 6V independent of VCC - eliminates need for external clamping in mixed-supply systems |
| Dual independent 3-state control | Separate 1OE and 2OE pins allow selective channel isolation without affecting other bus segments |
| Low propagation delay variation | tPLH/tPHL matching ≤0.5ns across channels - critical for skew-sensitive address/data buses |
| High noise immunity | VIL = 1.65V / VIH = 3.85V at VCC = 5.5V - provides >1.2V noise margin against EMI in industrial enclosures |
| Thermal performance | RθJA = 101.2°C/W in SOIC-20 - enables continuous operation at 85°C ambient with <150mW total dissipation |
Applications
| Memory Address Buffering | Industrial PLC Backplane Interface |
|---|---|
Use Scenario: Driving multiplexed address lines between microcontroller and SRAM/Flash in programmable logic controllers. IC Role / Device Role / Timing Role: Noninverting octal buffer with 3-state outputs isolating CPU from memory during DMA cycles. Use Value: 6.5ns max tPD ensures setup/hold compliance for 100MHz asynchronous memory access; 2V–6V VCC accommodates legacy 5V and modern 3.3V MCU cores. |
Use Scenario: Level-shifting and bus isolation between fieldbus controller (3.3V) and legacy I/O modules (5V) in modular PLC racks. IC Role / Device Role / Timing Role: Bidirectional bus driver enabling voltage translation without direction control logic. Use Value: Input tolerance to 6V permits direct connection to 5V fieldbus signals; independent OE pins allow staggered enable timing to prevent bus contention. |
| Network Switch Control Plane | Health Wearable Sensor Hub |
Use Scenario: Isolating configuration registers and status lines between management MCU and packet processing ASIC in Layer 2 switches. IC Role / Device Role / Timing Role: 3-state octal driver providing glitch-free register access during hot-swap events. Use Value: ±24mA drive supports long trace runs on backplanes; RθJA = 101.2°C/W sustains reliability in fanless 70°C chassis environments. |
Use Scenario: Multiplexing sensor data streams (accelerometer, HRM, SpO₂) to a low-power application processor in compact wearable form factors. IC Role / Device Role / Timing Role: Low-voltage buffer enabling 2.5V operation while accepting 3.3V sensor outputs. Use Value: 2V min VCC allows battery operation down to 2.4V; 45pF Cpd minimizes dynamic power in always-on sensor aggregation paths. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LVC240APWR | Lower VCC range (1.65–3.6V); 3.5ns tPD at 3.3V; ±24mA drive; 32mA max ICC | Better suited for 3.3V-only systems; not compatible with 5V buses or inputs | Select when operating exclusively in 3.3V domains and requiring faster switching than SN74AC240DW |
| SN74AHCT240N | 5V-only VCC (4.5–5.5V); TTL-compatible inputs; 7.5ns tPD at 5V; same SOIC-20 package | Requires 5V supply and generates higher ICC (40µA typical vs. 80µA max for AC) | Choose for legacy 5V systems needing TTL input thresholds and guaranteed 5V interoperability |
Compared with SN74LVC240APWR and SN74AHCT240N, the SN74AC240DW uniquely supports 2–6V operation with 6V-tolerant inputs, making it the only option among the three capable of bridging 3.3V and 5V subsystems without external level shifters or supply regulation.
Availability
SN74AC240DW is available at Aetrix Electronics and suitable for industrial PLC backplane interfaces, network switch control planes, and memory address buffering requiring stable component supply and long-term lifecycle assurance.
Supply support for SN74AC240DW 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 industrial, automotive, and communications markets.
The SN74AC240DW belongs to TI's AC-series advanced CMOS logic family, engineered for high-speed, low-power, mixed-voltage bus interfacing in industrial automation and networking equipment.
FAQ
What is the maximum supply voltage rating for SN74AC240DW?
The SN74AC240DW has an absolute maximum VCC rating of 7V, but its recommended operating range is 2V to 6V. Operation above 6V risks permanent damage, while below 2V may cause unreliable output states. The device maintains full functionality-including 6V-tolerant inputs-across this entire 2–6V window, making SN74AC240DW ideal for systems with variable or unregulated supplies.
Does SN74AC240DW support 3.3V logic levels when powered from 5V?
Yes, SN74AC240DW fully supports 3.3V logic levels at 5V VCC. Its VIH threshold is 3.85V and VIL is 1.65V at VCC = 5.5V, providing >1.2V noise margin for 3.3V CMOS outputs. Inputs tolerate up to 6V, so 3.3V signals drive cleanly without level shifting, and SN74AC240DW outputs swing rail-to-rail-ensuring reliable interfacing with both 3.3V and 5V receivers in mixed-voltage designs.
What is the thermal resistance (RθJA) of SN74AC240DW in its SOIC package?
The SN74AC240DW in SOIC-20 (DW) package has a junction-to-ambient thermal resistance (RθJA) of 101.2°C/W, measured under JEDEC-standard conditions (1-layer 2oz copper, 1in² pad). This value assumes standard PCB layout with adequate copper pour; actual thermal performance improves with enhanced heatsinking. At 85°C ambient and 150mW dissipation, junction temperature stays within safe limits (TJ ≈ 85 + 150mW × 101.2 ≈ 100°C), confirming SN74AC240DW suitability for fanless industrial deployments.
How does the dual output-enable architecture of SN74AC240DW improve system design?
SN74AC240DW features two independent active-low output-enable inputs (1OE and 2OE), allowing separate control of its two 4-bit channels. This enables precise bus arbitration-for example, holding one channel in high-Z while driving the other-eliminating contention during partial writes or hot-swap sequences. Unlike single-OE octal buffers, SN74AC240DW avoids unnecessary channel disablement, reducing signal integrity risk and simplifying timing-critical control logic in memory-mapped peripherals and backplane interfaces.
Is SN74AC240DW pin-compatible with other octal buffers in SOIC-20 packages?
SN74AC240DW shares the standard SOIC-20 (DW) footprint with multiple TI octal buffers-including SN74LVC240APWR and SN74AHCT240N-but pin functions differ. While all use Pin 1 (1OE), Pin 10 (GND), and Pin 20 (VCC) identically, output assignments (e.g., 1Y1 on Pin 18 vs. Pin 12 in AHCT variants) and input ordering vary. Substituting SN74AC240DW requires verification of logic diagram alignment and functional mode tables; it is not a drop-in replacement without schematic review and layout validation.
SN74AC240DW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AC
- Package/Case:
- 20-SOIC (0.295", 7.50mm 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-SOIC
SN74AC240DW FAQ
1.How can I place an order for SN74AC240DW through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AC240DW 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 SN74AC240DW reliable?
The price and inventory of SN74AC240DW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AC240DW is usually 5 days.
3.What payment methods are accepted for SN74AC240DW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AC240DW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74AC240DW?
SN74AC240DW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AC240DW 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 SN74AC240DW?
For technical support, including SN74AC240DW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AC240DW requirements.
6.How does Aetrix verify that SN74AC240DW is sourced from the original manufacturer or authorized distributors?
All SN74AC240DW 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 SN74AC240DW meets industry standards.
7.What is the process for return or replacement of SN74AC240DW?
All SN74AC240DW units undergo pre-shipment inspection (PSI). If there is an issue with SN74AC240DW, 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 SN74AC240DW part is unused and in its original packaging.
Return procedure for SN74AC240DW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SN74AC240DW Tags
-
SN74LVC1G17DBVR
Texas Instruments
-
SN74LVC1G07DCKR
Texas Instruments
-
SN74LVC1G17DCKR
Texas Instruments
-
SN74LVC1G07DBVR
Texas Instruments
-
SN74LVC1G125DCKR
Texas Instruments
-
SN74AHCT1G126DBVR
Texas Instruments
-
SN74LVC1G125DBVR
Texas Instruments
-
SN74AHCT1G125DBVR
Texas Instruments
-
SN74LVC2G17DBVR
Texas Instruments
-
SN74LVC2G07DCKR
Texas Instruments
-
SN74LVC1G34DCKR
Texas Instruments
-
SN74LVC2G17DCKR
Texas Instruments
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
