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Texas Instruments SN74AHCT240DWR
- Part No.:
- SN74AHCT240DWR
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74AHCT240DWR.pdf
- Description:
- IC BUFFER INVERT 5.5V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,432
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Product details
Overview
SN74AHCT240DWR from Texas Instruments is an octal inverting buffer/driver with tri-state outputs, designed for bus-oriented memory address and clock driving applications. It features TTL-compatible inputs (VIH = 2 V, VIL = 0.8 V), 5-V supply operation, ±8 mA output drive, and propagation delays as low as 9.5 ns at 50 pF load. It operates across –40°C to +125°C and is packaged in a 20-pin SOIC (DW) body measuring 12.8 mm × 10.3 mm.
For engineers reviewing the SN74AHCT240DWR datasheet, SN74AHCT240DWR pinout, SN74AHCT240DWR application, or SN74AHCT240DWR equivalent, this page delivers verified electrical specs, functional mode behavior, thermal metrics, real-world interface use cases, and validated alternative options for industrial bus buffering and level translation.
Technical Context
The SN74AHCT240DWR implements two independent 4-bit inverting buffer sections, each with dedicated active-low output-enable (OE) control. Its CMOS design accepts 3.3-V logic inputs while driving 5-V buses, enabling up-translation without external level shifters. Input thresholds are optimized for TTL compatibility, and slow edge rates suppress output ringing on lightly loaded traces.
Each section operates in one of two functional states: when OE is low, inverted data passes from A-inputs to Y-outputs; when OE is high, all four outputs enter high-impedance. The device requires no external pull-ups for power-up safety if OE is externally tied to VCC - a design requirement confirmed in TI's functional description and application guidance.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Supply | 4.5 V to 5.5 V - ensures stable operation in standard 5-V logic systems with ±10% tolerance. |
| VOH / VOL | 3.8 V min / 0.44 V max at 8 mA - guarantees robust logic-high and logic-low margins under full load. |
| tPLH / tPHL | 9.5 ns max at CL = 50 pF - supports reliable timing in 100-MHz-class bus interfaces with margin. |
| IOL / IOH | ±8 mA - sufficient to drive multiple 74-series TTL loads or terminate short PCB traces. |
| Operating Temp | –40°C to +125°C - qualified for extended industrial and automotive under-hood environments. |
| Input Compatibility | TTL-level (VIH = 2 V, VIL = 0.8 V) - interoperates directly with legacy 5-V TTL and modern 3.3-V microcontrollers. |
| RθJA | 81.1°C/W (SOIC DW) - enables thermal management with standard PCB copper pour and no forced airflow. |
Pinout & Package
SN74AHCT240DWR is housed in a 20-pin SOIC (DW) package with 12.8 mm × 10.3 mm footprint and 12.8 mm × 7.5 mm body size. Pin pitch is 1.27 mm, and the package is RoHS-compliant with NiPdAu lead finish and MSL Level-1 rating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1OE, 19OE | Active-low output enable (per section) | Controls tri-state behavior of respective 4-bit group; must be pulled high for safe power-up. |
| 1A1–1A4, 2A1–2A4 | Inverting input pins (8 total) | Accept TTL/CMOS logic; invert and route to corresponding Y outputs when OE is asserted. |
| 1Y1–1Y4, 2Y1–2Y4 | Inverting buffered outputs (8 total) | Drive external bus lines with controlled slew rate; enter high-Z when OE is deasserted. |
| VCC (Pin 20) | Positive supply | Must be decoupled with 0.1 µF ceramic capacitor placed adjacent to pin. |
| GND (Pin 10) | Ground reference | Return path for all I/O and supply currents; connects to system ground plane. |
Key Features
| Feature | Design Value |
|---|---|
| TTL-voltage compatible inputs | VIH = 2 V, VIL = 0.8 V - eliminates need for external level-shifting circuitry when interfacing with legacy 5-V TTL sources. |
| Tri-state output control | Dual independent OE pins - allows selective isolation of two 4-bit data paths on shared buses without contention. |
| Slow edge-rate design | Controlled slew minimizes overshoot/undershoot - reduces EMI and signal integrity issues on unterminated traces. |
| Latch-up immunity | Exceeds 250 mA per JESD17 - ensures robustness against transient current faults in noisy industrial environments. |
| Wide temperature range | –40°C to +125°C operation - supports deployment in automotive engine control units and industrial PLC backplanes. |
Applications
| Memory Address Buffering | Industrial Bus Isolation |
|---|---|
Use Scenario: Driving address lines between a microcontroller and parallel SRAM or flash memory in an embedded controller. IC Role / Device Role / Timing Role: Inverting buffer with tri-state control synchronizes address latching and prevents bus contention during memory access cycles. Use Value: Enables clean 5-V address propagation with 9.5 ns delay margin and guaranteed VIH/VIL compatibility with 3.3-V MCU GPIOs. | Use Scenario: Isolating CAN or RS-485 transceiver control lines from a host MCU in factory automation equipment. IC Role / Device Role / Timing Role: Level-translating buffer isolates logic domains and provides noise-immune signal routing to transceiver enable pins. Use Value: TTL-compatible inputs accept direct connection to 3.3-V MCU outputs; 8-mA drive ensures fast transceiver activation without external drivers. |
| Legacy System Interface | Power Infrastructure Monitoring |
Use Scenario: Interfacing modern ARM-based controllers with legacy 5-V peripheral cards in telecom rack systems. IC Role / Device Role / Timing Role: Bidirectional bus driver translating 3.3-V logic levels to 5-V backplane signaling standards. Use Value: Eliminates discrete resistor networks or dedicated level shifters; maintains timing integrity with sub-10 ns propagation delay. | Use Scenario: Conditioning sensor signals and control lines in smart grid metering hardware operating in high-EMI substations. IC Role / Device Role / Timing Role: Robust inverting buffer buffers fault-detection flags and status bits before transmission to isolated communication modules. Use Value: 250 mA latch-up immunity and 125°C rating ensure reliability in thermally stressed enclosures near power converters. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal inverting buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74AHCT240PW | TSSOP-20 package (6.5 mm × 6.4 mm); RθJA = 116.8°C/W - higher thermal resistance than SOIC DW. | Better board space efficiency but reduced power dissipation capability; unsuitable for high-ambient or high-duty-cycle use. | Select when PCB area is constrained and thermal load is light; verify junction temperature rise under worst-case conditions. |
| SN74LVC240APWR | 3.3-V only supply (1.65–3.6 V); LVCMOS input thresholds; 24 mA drive - incompatible with 5-V buses. | Not usable for 5-V level translation; requires separate 3.3-V rail and cannot replace SN74AHCT240DWR in mixed-voltage designs. | Choose only for pure 3.3-V systems where higher drive strength and lower voltage operation are required. |
Compared with SN74AHCT240PW and SN74LVC240APWR, the SN74AHCT240DWR uniquely supports 5-V bus interfacing with TTL-compatible inputs and SOIC thermal performance - making it the only drop-in solution for legacy 5-V industrial control backplanes requiring proven reliability and wide temperature operation.
Availability
SN74AHCT240DWR is available at Aetrix Electronics and suitable for industrial bus isolation, memory address buffering, and power infrastructure monitoring requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for SN74AHCT240DWR 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 delivering analog and embedded processing solutions, with over 90 years of innovation in logic, power, and signal chain technologies.
The SN74AHCT240 series belongs to TI's advanced high-speed CMOS logic family, engineered specifically for robust 5-V bus interfacing, level translation, and tri-state memory/address driving in industrial, automotive, and communications systems.
FAQ
What is the maximum output current per pin for SN74AHCT240DWR?
The SN74AHCT240DWR supports ±8 mA DC output current per Y-output pin under recommended operating conditions (VCC = 4.5 V to 5.5 V). Absolute maximum continuous output current is ±25 mA per pin, but sustained operation above ±8 mA may exceed thermal limits or degrade timing margins. The total device supply current must remain within ±75 mA to avoid exceeding absolute maximum ratings.
Does SN74AHCT240DWR support 3.3-V input logic levels?
Yes, SN74AHCT240DWR accepts 3.3-V logic inputs reliably: its VIH threshold is specified at 2.0 V minimum and VIL at 0.8 V maximum, allowing direct connection to 3.3-V CMOS or LVTTL outputs. This makes SN74AHCT240DWR ideal for up-translation to 5-V buses without external level shifters - a key feature confirmed in TI's functional description and application diagrams.
What is the recommended power supply decoupling for SN74AHCT240DWR?
TI recommends placing a 0.1 µF ceramic capacitor between VCC (Pin 20) and GND (Pin 10) as close as possible to the SN74AHCT240DWR package. This minimizes high-frequency supply noise and stabilizes switching transients. For systems with multiple logic devices sharing the same rail, additional bulk capacitance (e.g., 1.0 µF) may be added nearby, but the 0.1 µF local cap is mandatory per device per TI's layout guidance.
How does the tri-state functionality work on SN74AHCT240DWR?
SN74AHCT240DWR has two independent active-low output-enable inputs: 1OE (Pin 1) controls Y1–Y4, and 2OE (Pin 19) controls Y5–Y8. When an OE pin is low, its associated four outputs invert and drive their A-inputs; when high, those outputs enter high-impedance. Both OE pins must be actively driven or pulled high (e.g., via 10-kΩ resistor to VCC) to prevent floating states during power-up, as specified in TI's functional modes section.
Is SN74AHCT240DWR suitable for automotive under-hood applications?
Yes, SN74AHCT240DWR is rated for operation from –40°C to +125°C and meets JESD17 latch-up immunity (>250 mA), making it suitable for non-safety-critical automotive under-hood applications such as body control modules and powertrain sensor interfaces. It is not AEC-Q100 qualified, so for ASIL-B/C systems, additional validation per ISO 26262 is required - but its temperature and robustness specs align with common under-hood environmental demands.
SN74AHCT240DWR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AHCT
- Package/Case:
- 20-SOIC (0.295", 7.50mm 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:
- 8mA, 8mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
SN74AHCT240DWR FAQ
1.How can I place an order for SN74AHCT240DWR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AHCT240DWR 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 SN74AHCT240DWR reliable?
The price and inventory of SN74AHCT240DWR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AHCT240DWR is usually 5 days.
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SN74AHCT240DWR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AHCT240DWR 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 SN74AHCT240DWR?
For technical support, including SN74AHCT240DWR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AHCT240DWR requirements.
6.How does Aetrix verify that SN74AHCT240DWR is sourced from the original manufacturer or authorized distributors?
All SN74AHCT240DWR 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 SN74AHCT240DWR meets industry standards.
7.What is the process for return or replacement of SN74AHCT240DWR?
All SN74AHCT240DWR units undergo pre-shipment inspection (PSI). If there is an issue with SN74AHCT240DWR, 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 SN74AHCT240DWR part is unused and in its original packaging.
Return procedure for SN74AHCT240DWR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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