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Texas Instruments SN74AHCT240PW
- Part No.:
- SN74AHCT240PW
- Manufacturer:
- Texas Instruments
- Package:
- 20-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
SN74AHCT240PW.pdf
- Description:
- IC BUFFER INVERT 5.5V 20TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,238
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Product details
Overview
SN74AHCT240PW 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 (4.5–5.5 V), ±8 mA output drive, 9.5 ns max propagation delay (CL = 50 pF), and operates across –40°C to +125°C. Used in network switches and TV backplanes for level translation and bus isolation.
For engineers reviewing the SN74AHCT240PW datasheet, SN74AHCT240PW pinout, SN74AHCT240PW application, or SN74AHCT240PW equivalent, key selection criteria include tri-state enable timing (tPZH/tPLZ ≤ 14 ns), input voltage compatibility with 3.3-V logic, thermal resistance (RθJA = 116.8°C/W), and TSSOP-20 package footprint constraints.
Technical Context
The SN74AHCT240PW implements two independent 4-bit inverting buffer sections, each with dedicated output-enable (OE) control. Its CMOS design with TTL-input thresholds enables reliable 3.3-V-to-5-V up-translation while maintaining slow edge rates to suppress output ringing on lightly loaded buses.
Functional mode is strictly controlled by OE: low enables inverted A→Y transfer; high forces all eight Y outputs into high-impedance state. Input clamp current exceeds ±20 mA, and latch-up performance meets JESD17 (>250 mA), supporting robust operation in noisy industrial environments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - ensures compatibility with standard 5-V logic rails and tolerance against supply droop. |
| Input Thresholds | VIH = 2.0 V, VIL = 0.8 V - guarantees interoperability with legacy TTL and 3.3-V CMOS outputs without level shifters. |
| Output Drive | ±8 mA - sufficient for driving multiple CMOS loads or short PCB traces, but requires external termination for long lines. |
| Propagation Delay | ≤9.5 ns (CL = 50 pF) - supports bus speeds up to ~50 MHz in point-to-point configurations. |
| Operating Temperature | –40°C to +125°C - qualified for automotive under-hood and industrial control applications. |
| Thermal Resistance | RθJA = 116.8°C/W - mandates careful PCB copper pour and thermal vias for sustained 75 mA total output current. |
| ESD Rating | HBM ±2000 V - meets IEC 61000-4-2 Level 2 for handling in non-ESD-protected assembly areas. |
Pinout & Package
TSSOP-20 (PW) package: 6.50 mm × 6.40 mm body size, 0.65 mm lead pitch, thin profile suitable for space-constrained PCB layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | OE (1 & 2) | Active-low enable controls inversion and tri-state behavior per 4-bit section - tie high via pull-up during power sequencing to prevent bus contention. |
| 2, 4, 6, 8, 11, 13, 15, 17 | A1–A4, 2A1–2A4 | Eight buffered data inputs - TTL-compatible; accept 0–5.5 V regardless of VCC, enabling mixed-voltage system interfacing. |
| 3, 5, 7, 9, 12, 14, 16, 18 | Y1–Y4, 2Y1–2Y4 | Inverted, tri-state outputs - high-impedance when respective OE is high; sink/source up to ±8 mA per pin. |
| 10 | GND | Ground reference - must be low-inductance connection; separate analog/digital ground planes require single-point tie near device. |
| 20 | VCC | 5-V power supply - requires local 0.1 µF ceramic bypass capacitor placed within 3 mm of pin to suppress switching noise. |
Key Features
| Feature | Design Value |
|---|---|
| TTL-input compatibility | Accepts 0.8 V/2.0 V thresholds - eliminates need for external level translators when interfacing with legacy microcontrollers or FPGAs. |
| Controlled edge rate | Slower rise/fall times reduce EMI and overshoot on unterminated transmission lines - critical for clean signal integrity in dense routing. |
| High-impedance isolation | Dual OE pins allow independent gating of two 4-bit channels - enables dynamic bus arbitration without external logic. |
| Latch-up immunity | Exceeds 250 mA per JESD17 - withstands transient overcurrent events common in hot-plug or fault-recovery scenarios. |
| Overvoltage-tolerant inputs | Withstand VI up to 5.5 V even at VCC = 0 V - supports safe power sequencing where inputs may be driven before VCC ramps. |
Applications
| Network Switch Backplane Interface | Industrial PLC I/O Expansion |
|---|---|
Use Scenario: Isolating CPU address/data buses from modular I/O cards in 1U rack-mounted Ethernet switches. IC Role / Device Role / Timing Role: Tri-state buffer providing direction-controlled, inverted address latching between ASIC and peripheral modules. Use Value: Prevents bus contention during card hot-swap; 9.5 ns delay ensures setup/hold timing margins for 25-MHz synchronous transfers. | Use Scenario: Driving isolated digital output banks in programmable logic controllers with mixed 3.3-V FPGA and 5-V relay driver stages. IC Role / Device Role / Timing Role: Level-translating buffer converting FPGA GPIO signals to 5-V compatible levels while enabling/disabling groups via OE. Use Value: Eliminates discrete level-shifter components; ±8 mA drive directly interfaces with optocoupler inputs without external transistors. |
| Smart TV Mainboard Memory Buffer | Automotive Infotainment Display Interface |
Use Scenario: Buffering DDR address/control lines between SoC and LPDDR3 memory subsystem in ultra-thin television mainboards. IC Role / Device Role / Timing Role: Inverting driver isolating memory controller outputs during refresh cycles using OE-controlled tri-state. Use Value: Reduces capacitive loading on SoC pins; slow edges minimize crosstalk on adjacent high-speed video traces. | Use Scenario: Interfacing infotainment head-unit MCU with 5-V display timing controller in vehicles operating across –40°C to +105°C ambient. IC Role / Device Role / Timing Role: Temperature-hardened bus driver translating MCU GPIO to display interface signals with fail-safe OE control. Use Value: Guaranteed operation at 125°C junction temperature supports placement near heat-generating power stages; HBM ±2000 V protects against dashboard ESD events. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal inverting buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74AHCT240PWR | Same silicon, identical electrical specs, TSSOP-20 package, active production status vs. SN74AHCT240PW's obsolete status. | Direct replacement with guaranteed long-term availability and full TI support lifecycle. | Select SN74AHCT240PWR for new designs requiring assured supply continuity and full documentation access. |
| 74LVC240APW | 3.3-V only supply (1.65–3.6 V), lower drive (±24 mA), faster propagation (≤5.5 ns), different input thresholds (VIH = 2.0 V min at VCC = 3.3 V). | Not suitable for 5-V systems; requires redesign of supply and level-shifting if migrating from SN74AHCT240PW. | Consider only for 3.3-V-native designs needing higher speed and lower power; not a drop-in substitute. |
Compared with SN74AHCT240PW, SN74AHCT240PWR offers identical functionality with assured supply chain continuity, while 74LVC240APW trades 5-V compatibility for higher speed and lower voltage operation - necessitating full system-level validation.
Availability
SN74AHCT240PW is available at Aetrix Electronics and suitable for network switch backplanes, industrial PLC I/O expansion, and smart TV memory buffering requiring stable component supply across extended temperature ranges and long product lifecycles.
Supply support for SN74AHCT240PW 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 SNx4AHCT240 product line delivers TTL-compatible, 5-V CMOS buffers optimized for bus isolation, level translation, and memory interface applications in harsh-environment systems.
FAQ
What is the maximum operating temperature for SN74AHCT240PW?
The SN74AHCT240PW is rated for operation from –40°C to +125°C ambient temperature. This specification is validated per TI's characterization and production testing protocols for the TSSOP-20 package variant, ensuring reliability in automotive under-hood and industrial control environments where thermal management is constrained.
Does SN74AHCT240PW support 3.3-V input logic levels?
Yes, SN74AHCT240PW accepts 3.3-V logic inputs reliably: its VIH threshold is 2.0 V minimum and VIL is 0.8 V maximum, allowing direct connection to 3.3-V CMOS or LVTTL outputs without external level shifting - a core design feature enabling 3.3-V-to-5-V up-translation.
What is the recommended bypass capacitor for SN74AHCT240PW?
A 0.1 µF ceramic capacitor is recommended for SN74AHCT240PW, placed as close as possible (≤3 mm) to the VCC pin (pin 20) and GND (pin 10). This minimizes high-frequency supply noise and stabilizes internal rail voltage during output switching transitions, especially critical given the device's 75 mA total supply current capability.
Can SN74AHCT240PW outputs drive LEDs directly?
No, SN74AHCT240PW outputs are not intended for direct LED driving. Its ±8 mA per-output rating is insufficient for typical indicator LEDs (requiring 10–20 mA), and the device lacks current-limiting or thermal protection. Use external series resistors and verify voltage drop; for robust LED control, pair SN74AHCT240PW with dedicated LED drivers or discrete transistors.
Is SN74AHCT240PW pin-compatible with other AHCT240 variants?
Yes, SN74AHCT240PW shares identical pinout and function with all SN74AHCT240 variants in 20-pin packages (e.g., DW, DB, NS, N), including matching OE, A, Y, VCC, and GND positions. However, mechanical dimensions and thermal characteristics differ - TSSOP-20 (PW) has smaller body size and higher RθJA than SOIC-20 (DW), affecting layout and thermal design.
SN74AHCT240PW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AHCT
- 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:
- 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-TSSOP
SN74AHCT240PW FAQ
1.How can I place an order for SN74AHCT240PW through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AHCT240PW 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 SN74AHCT240PW reliable?
The price and inventory of SN74AHCT240PW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AHCT240PW is usually 5 days.
3.What payment methods are accepted for SN74AHCT240PW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AHCT240PW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74AHCT240PW?
SN74AHCT240PW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AHCT240PW 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 SN74AHCT240PW?
For technical support, including SN74AHCT240PW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AHCT240PW requirements.
6.How does Aetrix verify that SN74AHCT240PW is sourced from the original manufacturer or authorized distributors?
All SN74AHCT240PW 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 SN74AHCT240PW meets industry standards.
7.What is the process for return or replacement of SN74AHCT240PW?
All SN74AHCT240PW units undergo pre-shipment inspection (PSI). If there is an issue with SN74AHCT240PW, 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 SN74AHCT240PW part is unused and in its original packaging.
Return procedure for SN74AHCT240PW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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