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Texas Instruments SN74AHCT240N
- Part No.:
- SN74AHCT240N
- Manufacturer:
- Texas Instruments
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
SN74AHCT240N.pdf
- Description:
- IC BUFFER INVERT 5.5V 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,208
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Product details
Overview
SN74AHCT240N from Texas Instruments is an octal inverting buffer/driver with tri-state outputs, designed for memory-address, clock, and bus-oriented 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 7.4 ns (CL = 15 pF) - enabling reliable level translation and bus isolation in industrial control systems.
For engineers reviewing the SN74AHCT240N datasheet, SN74AHCT240N pinout, SN74AHCT240N application, or SN74AHCT240N equivalent, this page delivers verified electrical specs, validated PDIP-20 package details, functional mode behavior, real-world use cases, and two confirmed alternative parts - all grounded in TI's SCLS252P production data sheet.
Technical Context
The SN74AHCT240N implements two independent 4-bit inverting buffer sections, each with dedicated output-enable (OE) control. Its CMOS design operates at 4.5–5.5 V, accepts 3.3-V TTL logic inputs, and provides high-impedance outputs when OE is high - supporting bidirectional bus management without contention.
Each output delivers ±8 mA sink/source capability under 5-V operation, with slow edge rates minimizing ringing on lightly loaded traces. Input clamping and latch-up immunity (>250 mA per JESD17) ensure robustness in noisy industrial environments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - compatible with standard 5-V logic rails and tolerant of typical power rail variation. |
| Input Voltage Compatibility | TTL-level: VIH = 2 V min, VIL = 0.8 V max - enables direct interfacing with legacy 3.3-V and 5-V TTL sources. |
| Output Drive Strength | ±8 mA at VCC = 4.5 V - sufficient for driving multiple CMOS loads or short PCB traces without external buffering. |
| Propagation Delay | 7.4 ns max (A-to-Y, CL = 15 pF) - supports >100 MHz bus toggle rates in point-to-point configurations. |
| Operating Temperature | –40°C to +125°C - qualified for extended industrial and automotive under-hood applications. |
| ESD Rating | ±2000 V HBM - meets JEDEC JS-001 for handling in standard assembly environments. |
| Quiescent Current | 40 µA max at VCC = 5.5 V - enables low-static-power system states during tri-state idle periods. |
Pinout & Package
SN74AHCT240N uses a 20-pin plastic dual in-line package (PDIP) with 25.40 mm × 6.35 mm body size and 24.33 mm × 9.4 mm overall footprint. Pin 10 is GND; Pin 20 is VCC; both OE inputs are active-low and independently control their respective 4-bit sections.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | 1OE, 2OE | Active-low output enable for Section 1 and Section 2 - drives outputs to high-Z when high; enables inverted A→Y transfer when low. |
| 2, 4, 6, 8, 11, 13, 15, 17 | 1A1–1A4, 2A1–2A4 | Buffer input pins - accept TTL-compatible signals; inversion occurs internally before output. |
| 3, 5, 7, 9, 12, 14, 16, 18 | 2Y4–2Y1, 1Y4–1Y1 | Inverted output pins - deliver complemented logic state of corresponding A inputs when OE is asserted. |
| 10 | GND | Ground reference - must be connected to system common; decoupling capacitor recommended adjacent to Pin 20. |
| 20 | VCC | Positive supply - requires local 0.1 µF ceramic bypass capacitor to suppress switching noise and maintain stable logic thresholds. |
Key Features
| Feature | Design Value |
|---|---|
| TTL-voltage compatible inputs | Accepts 0.8 V / 2 V thresholds - eliminates need for external level shifters when interfacing with legacy 3.3-V or 5-V TTL logic. |
| Tri-state output control | Dual independent OE pins allow selective isolation of either 4-bit section - essential for shared bus arbitration and hot-swap compatibility. |
| Slow edge rate design | Controlled slew minimizes overshoot/undershoot on unterminated lines - reduces EMI and signal integrity risk in compact layouts. |
| Latch-up immunity | Exceeds 250 mA per JESD17 - ensures survivability during transient overcurrent events in industrial power domains. |
| 5-V optimized CMOS process | Delivers rail-to-rail output swing (VOH ≥ 3.8 V, VOL ≤ 0.44 V at 8 mA) while maintaining low ICC quiescent current. |
Applications
| Industrial PLC Backplane Interface | Legacy Display Controller Bus Isolation |
|---|---|
Use Scenario: Isolating microcontroller address/data buses from relay driver banks in programmable logic controllers. IC Role / Device Role / Timing Role: Octal inverting buffer with tri-state control acts as directionally gated address latch and noise-suppressed bus driver. Use Value: Prevents bus contention during firmware updates; slow edges reduce conducted emissions on 24-VDC field wiring runs. |
Use Scenario: Interfacing modern ARM-based display controllers with legacy 5-V segment drivers in medical panel displays. IC Role / Device Role / Timing Role: Level-translating buffer converts 3.3-V GPIO outputs to 5-V TTL-compatible signals while providing output disable during boot sequence. Use Value: Eliminates need for discrete resistor networks; OE-controlled high-Z state avoids phantom activation of segments during initialization. |
| Automotive Body Control Module I/O Expansion | Test Equipment Signal Conditioning Stage |
Use Scenario: Expanding GPIO count for door lock actuator sequencing and sensor polling in vehicle body control units. IC Role / Device Role / Timing Role: Inverting buffer section drives optocoupler inputs; OE pins synchronized with CAN message frames to gate diagnostic signals. Use Value: –40°C to +125°C rating ensures operation across full automotive ambient range; latch-up immunity withstands load dump transients. |
Use Scenario: Conditioning digital stimulus signals before injection into DUTs during automated functional test of mixed-signal boards. IC Role / Device Role / Timing Role: Output-enable controlled inversion stage buffers pattern generator outputs while suppressing reflections on 50-Ω coaxial paths. Use Value: 7.4 ns propagation delay enables precise timing alignment; low Cpd (10 pF) minimizes capacitive loading on high-speed test vectors. |
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 (6.50 mm × 6.40 mm); 116.8°C/W RθJA; RoHS-compliant NIPDAU finish. | Higher board density; unsuitable for through-hole prototyping or wave soldering. | Select for space-constrained PCBs requiring surface-mount assembly and thermal performance within 125°C ambient. |
| SN74AHCT240DWR | SOIC-20 package (12.80 mm × 10.30 mm); 81.1°C/W RθJA; same pinout and electrical specs as SN74AHCT240N. | Compatible with reflow and wave soldering; better thermal dissipation than PDIP but larger footprint. | Choose when upgrading from PDIP to surface-mount without redesigning layout - identical function and timing. |
Compared with SN74AHCT240N, SN74AHCT240PW offers superior packaging density but reduced thermal margin, while SN74AHCT240DWR provides identical functionality in a surface-mount SOIC variant with improved heat transfer - making it ideal for drop-in replacement in upgraded manufacturing flows.
Availability
SN74AHCT240N is available at Aetrix Electronics and suitable for industrial PLC backplanes, automotive body control modules, legacy display interfaces, and automated test equipment requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for SN74AHCT240N 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 decades of experience in industrial-grade interface ICs.
The SN74AHCT240N belongs to TI's AHCT logic family - engineered for 5-V systems requiring TTL compatibility, low power, and robust noise immunity in harsh electromagnetic environments.
FAQ
What is the maximum output current per pin for SN74AHCT240N?
The SN74AHCT240N supports ±8 mA per output pin at VCC = 4.5 V, as specified in its electrical characteristics table. This allows driving multiple CMOS inputs or short PCB traces. Total device output current must not exceed ±75 mA, and continuous current through VCC or GND is limited to ±75 mA - ensuring safe operation under sustained load conditions without thermal derating.
Does SN74AHCT240N support 3.3-V input logic levels?
Yes, SN74AHCT240N accepts 3.3-V TTL-compatible inputs: VIH is guaranteed ≥2 V and VIL ≤0.8 V across the full operating temperature range. This allows direct connection to 3.3-V microcontrollers and FPGAs without level-shifting circuitry - a key feature enabling voltage translation from 3.3 V to 5 V in mixed-supply systems.
How does the tri-state functionality work on SN74AHCT240N?
SN74AHCT240N has two independent active-low output-enable inputs (1OE and 2OE). When an OE pin is low, its corresponding 4-bit section passes inverted data from A inputs to Y outputs. When OE is high, all eight outputs enter high-impedance state - electrically disconnecting them from the bus. This enables time-multiplexed sharing of data/address lines among multiple devices.
What is the recommended bypass capacitor for SN74AHCT240N?
A 0.1 µF ceramic capacitor is recommended between VCC (Pin 20) and GND (Pin 10) for SN74AHCT240N, placed as close as possible to the pins. This minimizes high-frequency supply noise and stabilizes internal logic thresholds during output transitions. For systems with multiple logic ICs, parallel 0.1 µF and 1.0 µF capacitors further improve broadband noise suppression.
Is SN74AHCT240N suitable for automotive applications?
Yes, SN74AHCT240N is rated for –40°C to +125°C operation and meets JESD17 latch-up immunity (>250 mA), making it suitable for non-safety-critical automotive applications such as body control modules and infotainment subsystems. It is not AEC-Q200 qualified, so functional safety-critical systems require additional validation per ISO 26262 requirements.
SN74AHCT240N Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AHCT
- Package/Case:
- 20-DIP (0.300", 7.62mm)
- Packaging:
- Bulk
- 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:
- Through Hole
- Supplier Device Package:
- 20-PDIP
SN74AHCT240N FAQ
1.How can I place an order for SN74AHCT240N through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AHCT240N 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 SN74AHCT240N reliable?
The price and inventory of SN74AHCT240N are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AHCT240N is usually 5 days.
3.What payment methods are accepted for SN74AHCT240N?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AHCT240N transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74AHCT240N?
SN74AHCT240N orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AHCT240N 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 SN74AHCT240N?
For technical support, including SN74AHCT240N datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AHCT240N requirements.
6.How does Aetrix verify that SN74AHCT240N is sourced from the original manufacturer or authorized distributors?
All SN74AHCT240N 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 SN74AHCT240N meets industry standards.
7.What is the process for return or replacement of SN74AHCT240N?
All SN74AHCT240N units undergo pre-shipment inspection (PSI). If there is an issue with SN74AHCT240N, 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 SN74AHCT240N part is unused and in its original packaging.
Return procedure for SN74AHCT240N:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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