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Texas Instruments SN74HCT240PW
- Part No.:
- SN74HCT240PW
- Manufacturer:
- Texas Instruments
- Package:
- 20-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
SN74HCT240PW.pdf
- Description:
- IC BUFFER INVERT 5.5V 20TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:754
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Product details
Overview
SN74HCT240PW from Texas Instruments is an octal inverting buffer/line driver with 3-state outputs, designed for memory address and bus driving in 5V TTL-compatible systems. It operates from 4.5V to 5.5V, delivers ±6mA output drive, exhibits 12ns typical propagation delay at 5.5V, and draws ≤80μA quiescent current - enabling high-density bus interfacing in industrial control backplanes.
For engineers reviewing the SN74HCT240PW datasheet, SN74HCT240PW pinout, SN74HCT240PW application, or SN74HCT240PW equivalent, key selection criteria include its dual 4-bit inverting architecture with independent OE controls, TSSOP-20 package footprint, 3-state output compatibility with LSTTL loads, and guaranteed operation across −40°C to +85°C.
Technical Context
The SN74HCT240PW implements two independent 4-bit inverting buffer sections, each with dedicated output-enable (OE) inputs (Pin 1 and Pin 19). When OE is low, inverted data passes from A-inputs (Pins 2,4,6,8 and 11,13,15,17) to Y-outputs (Pins 3,5,7,9 and 12,14,16,18); when OE is high, all eight outputs enter high-impedance state. This enables bidirectional bus control without external logic.
Its HCT logic family ensures TTL-voltage-level compatibility (VIH = 2V min, VIL = 0.8V max at VCC = 4.5–5.5V), while CMOS input structure limits II ≤ 1μA. The device drives up to 15 LSTTL loads and maintains stable switching performance under CL = 50 pF and CL = 150 pF load conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5V to 5.5V - compatible with standard 5V logic rails and tolerant of supply ripple |
| Propagation Delay | 12ns typical at 5.5V, CL = 50 pF - supports >30 MHz bus clocking in address/data paths |
| Output Drive | ±6mA at 5V - sufficient to directly drive 15 LSTTL inputs without buffering |
| Quiescent Current | ≤80μA max - enables low-power standby in battery-backed or energy-sensitive systems |
| Input Compatibility | TTL-voltage levels (VIH ≥ 2V, VIL ≤ 0.8V) - interoperable with legacy 74LS and microcontroller GPIO |
| Operating Temperature | −40°C to +85°C - qualified for industrial-grade embedded applications |
| 3-State Enable Time | 19ns typical (ten) at 5.5V - ensures fast bus release for time-critical arbitration |
Pinout & Package
TSSOP-20 (PW) package: 6.50mm × 6.4mm body size, 1.2mm max height, 0.65mm lead pitch, exposed thermal pad optional per TI SLMA002/SLMA004 guidelines.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | 1OE, 2OE | Active-low enable inputs - independently control inversion and 3-state behavior of each 4-bit section |
| 2,4,6,8,11,13,15,17 | 1A1–1A4, 2A1–2A4 | Inverting data inputs - accept TTL-level signals; drive corresponding Y outputs when OE active |
| 3,5,7,9,12,14,16,18 | 1Y1–1Y4, 2Y1–2Y4 | Inverting 3-state outputs - pass inverted A-inputs when OE low; high-Z when OE high |
| 10 | GND | Ground reference - must be low-impedance connection to minimize noise coupling |
| 20 | VCC | Power supply - requires local 0.1μF ceramic bypass capacitor per TI recommendations |
Key Features
| Feature | Design Value |
|---|---|
| Inverting 3-state buffers | Dual 4-bit sections enable compact address/data bus isolation with polarity control |
| TTL-compatible inputs | Accepts standard 74LS logic thresholds without level-shifting circuitry |
| High-output current | ±6mA drive capability eliminates need for external bus transceivers in moderate-load designs |
| Low ICC | ≤80μA max quiescent current reduces system power budget impact during idle states |
| Fast enable/disable | 19ns typical output-enable time supports rapid bus turnaround in multiplexed architectures |
Applications
| Memory Address Buffering | Industrial Bus Transceiver |
|---|---|
Use Scenario: Driving 20-bit address lines from a microcontroller to multiple SRAM or EPROM devices on a shared bus. IC Role / Device Role / Timing Role: Inverting 3-state buffer isolating CPU address outputs from memory chip inputs; enables multi-drop addressing with OE-controlled contention avoidance. Use Value: Eliminates need for discrete inverters and tristate logic gates, reducing BOM count and PCB area by consolidating eight channels in one TSSOP-20 package. | Use Scenario: Interfacing PLC I/O modules to a central controller via a parallel status/data bus. IC Role / Device Role / Timing Role: Bidirectional bus driver providing controlled signal directionality and voltage translation between 5V logic domains. Use Value: Supports hot-swap-safe bus arbitration via independent OE pins, preventing bus contention during module insertion/removal. |
| Legacy System Interface | Test Equipment Signal Conditioning |
Use Scenario: Adapting modern FPGA GPIO to legacy 74LS-based peripheral cards requiring inverted address strobes. IC Role / Device Role / Timing Role: Level- and polarity-translating interface element matching TTL input thresholds and inverting timing signals like ALE or MREQ. Use Value: Enables drop-in replacement of obsolete 74LS240 without redesigning timing margins or adding external pull-ups. | Use Scenario: Conditioning digital stimulus/response signals in automated test equipment where precise edge timing and load driving are critical. IC Role / Device Role / Timing Role: Low-jitter, high-drive buffer ensuring clean signal integrity across long PCB traces or cables to DUT interfaces. Use Value: Delivers 12ns typical tpd and ±6mA drive to maintain signal fidelity at 30+ MHz, reducing measurement uncertainty in high-speed functional tests. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal inverting buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HCT240PWR | Same silicon, TSSOP-20 tape-and-reel packaging (2000 pcs/reel); active production status vs. SN74HCT240PW's obsolete status | Identical electrical and timing behavior; suitable for new designs requiring volume procurement | Select SN74HCT240PWR for new designs - identical functionality with guaranteed supply continuity and RoHS compliance. |
| SN74ACT240PW | ACT family: 4.5–5.5V supply, but higher speed (8ns tpd), higher drive (±24mA), and CMOS input thresholds (VIH = 3.5V min) | Not TTL-compatible; requires 3.5V+ logic-high inputs - unsuitable for direct 74LS interface without level shifting | Choose SN74ACT240PW only when higher speed and drive are needed and system logic thresholds support ACT-level inputs. |
Compared with SN74HCT240PW, SN74HCT240PWR offers identical performance with assured availability, while SN74ACT240PW trades TTL compatibility for speed and drive strength - making the former the preferred drop-in alternative and the latter a functional upgrade requiring input threshold validation.
Availability
SN74HCT240PW is available at Aetrix Electronics and suitable for industrial control backplanes, legacy system upgrades, and test equipment signal conditioning requiring stable component supply and verified 5V bus-driving capability.
Supply support for SN74HCT240PW 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, embedded processing, and logic solutions for industrial, automotive, and communications markets.
The SN74HCT240PW belongs to TI's 74HCT logic family, engineered for TTL-compatible operation in 5V systems where low power, predictable timing, and robust bus-driving capability are essential.
FAQ
What is the function of the SN74HCT240PW?
The SN74HCT240PW is an octal inverting buffer/line driver with 3-state outputs. It contains two independent 4-bit sections, each with dedicated output-enable inputs. When enabled, it inverts and drives data from A inputs to Y outputs; when disabled, outputs enter high-impedance state - ideal for bus isolation and memory address driving.
Does the SN74HCT240PW support TTL-level inputs?
Yes, the SN74HCT240PW features TTL-voltage-compatible inputs: VIH ≥ 2.0V and VIL ≤ 0.8V over the full 4.5V–5.5V supply range. This allows direct interfacing with legacy 74LS devices and microcontrollers without level-shifting circuitry.
What is the maximum output current rating for the SN74HCT240PW?
The SN74HCT240PW provides ±6mA output drive per pin at VCC = 5V, as specified in its Electrical Characteristics table. This enables direct driving of up to 15 LSTTL loads per output, supporting robust bus termination and fanout requirements.
Is the SN74HCT240PW still in active production?
No - the SN74HCT240PW (tube-packaged variant) is marked obsolete in TI's packaging addendum. However, the functionally identical SN74HCT240PWR (tape-and-reel) remains active and fully recommended for new designs requiring the same specifications and TSSOP-20 footprint.
What thermal considerations apply to the SN74HCT240PW in TSSOP-20 package?
The SN74HCT240PW in PW package has a junction-to-ambient thermal resistance (RθJA) of 131.8°C/W. For reliable operation at full drive, ensure adequate PCB copper area and consider thermal vias beneath the exposed pad per TI SLMA002 guidelines - especially in ambient temperatures approaching +85°C.
SN74HCT240PW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HCT
- Package/Case:
- 20-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tube
- 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:
- 6mA, 6mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-TSSOP
SN74HCT240PW FAQ
1.How can I place an order for SN74HCT240PW through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74HCT240PW 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 SN74HCT240PW reliable?
The price and inventory of SN74HCT240PW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74HCT240PW is usually 5 days.
3.What payment methods are accepted for SN74HCT240PW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74HCT240PW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74HCT240PW?
SN74HCT240PW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74HCT240PW 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 SN74HCT240PW?
For technical support, including SN74HCT240PW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74HCT240PW requirements.
6.How does Aetrix verify that SN74HCT240PW is sourced from the original manufacturer or authorized distributors?
All SN74HCT240PW 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 SN74HCT240PW meets industry standards.
7.What is the process for return or replacement of SN74HCT240PW?
All SN74HCT240PW units undergo pre-shipment inspection (PSI). If there is an issue with SN74HCT240PW, 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 SN74HCT240PW part is unused and in its original packaging.
Return procedure for SN74HCT240PW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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