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Texas Instruments SN74HC240NSRE4
- Part No.:
- SN74HC240NSRE4
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
SN74HC240NSRE4.pdf
- Description:
- IC BUFFER INVERT 6V 20SO
- Quantity:
- Payment:
- Shipping:
Inventory:1,515
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Product details
Overview
SN74HC240NSRE4 from Texas Instruments is an octal inverting buffer/line driver with 3-state outputs, designed for memory address and bus driving applications. It operates from 2V to 6V, delivers ±6mA output drive at 5V, features typical propagation delay of 9ns, and consumes ≤80µA ICC - enabling high-density, low-power bus interfacing in industrial control and embedded systems.
For engineers reviewing the SN74HC240NSRE4 datasheet, SN74HC240NSRE4 pinout, SN74HC240NSRE4 application, or SN74HC240NSRE4 equivalent, key selection criteria include its dual 4-bit inverting architecture, independent OE controls, 3-state output behavior, and SOP-20 package compatibility with legacy PCB layouts requiring space-constrained surface-mount solutions.
Technical Context
The SN74HC240NSRE4 implements two independent 4-bit inverting buffer sections, each with dedicated output-enable (OE) inputs. When OE is low, inverted logic passes from A inputs to Y outputs; when OE is high, outputs enter high-impedance state - enabling bidirectional bus arbitration and memory address multiplexing without external logic.
It uses standard CMOS silicon process with Schmitt-trigger input thresholds omitted; all inputs are TTL-compatible and require explicit biasing. The device supports rail-to-rail operation across 2V–6V, exhibits 1µA max input leakage, and maintains stable 3-state transition timing (tdis ≤32ns, ten ≤43ns at 6V/CL=150pF), critical for glitch-free bus sharing in synchronous digital systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 2V to 6V - enables direct interface with 3.3V and 5V logic families without level shifters |
| Output Drive | ±6mA at 5V - sufficient to drive 15 LSTTL loads, supporting legacy TTL bus loading requirements |
| Propagation Delay | 9ns typical at 4.5V - ensures sub-10ns timing margin for 50MHz+ address/data strobes |
| Quiescent Current | ≤80µA max ICC - reduces standby power in battery-backed or energy-sensitive systems |
| Input Leakage | ≤1µA max - prevents unintended logic transitions on unterminated or high-impedance traces |
| 3-State Enable Time | ≤43ns max ten at 6V/CL=150pF - guarantees fast bus release for time-critical arbitration protocols |
Pinout & Package
SOP-20 (NS) package: 12.6mm × 7.8mm body, 20-pin surface-mount, gull-wing leads, RoHS-compliant NiPdAu finish, MSL Level-1 (260°C reflow).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | 1OE, 2OE | Active-low enable inputs controlling respective 4-bit inverting sections - must be pulled low for functional output |
| 2–4, 6–8, 11–13, 15–17 | A1–A4, A1–A4 | Eight buffered input terminals - inverted data appears at corresponding Y outputs when OE active |
| 3, 5, 7, 9, 12, 14, 16, 18 | Y1–Y4, Y1–Y4 | Eight 3-state inverting outputs - high-impedance when OE high, enabling shared bus topology |
| 10 | GND | Ground reference for all logic and output stages - requires low-inductance connection to system ground plane |
| 20 | VCC | Power supply pin - must be decoupled with 0.1µF ceramic capacitor placed within 2mm of pin |
Key Features
| Feature | Design Value |
|---|---|
| Inverting 3-state buffers | Enables memory address latching and bus contention management via dual independent OE controls |
| Wide VCC range (2–6V) | Supports mixed-voltage system integration without external regulators or translators |
| Low ICC (≤80µA) | Reduces system-level quiescent power in always-on industrial controllers and IoT edge nodes |
| High noise immunity | VIH/VIL thresholds scale with VCC - maintains >1.3V noise margin at 5V operation |
| TTL-compatible drive | Direct replacement for 74LS240 in legacy designs, eliminating need for pull-up resistors or voltage translation |
Applications
| Memory Address Buffering | Industrial Bus Interface |
|---|---|
Use Scenario: Driving 16-bit address lines from microcontroller to SRAM or EPROM in PLC backplane modules. IC Role / Device Role / Timing Role: Inverting 3-state buffer isolating CPU address bus from memory array; OE synchronized with memory enable signal. Use Value: Prevents address bus contention during DMA cycles and enables clean address setup/hold timing per JEDEC standards. | Use Scenario: Interfacing multiple sensor nodes to a central CAN or RS-485 master controller via shared parallel control bus. IC Role / Device Role / Timing Role: Bidirectional bus driver managing read/write handshaking signals (RD#, WR#, CS#) across distributed I/O modules. Use Value: Eliminates bus lockup during hot-swap events by ensuring only one node drives signals while others remain in high-Z state. |
| Clock Distribution | Legacy System Upgrade |
Use Scenario: Fan-out of system clock to multiple peripheral ICs (ADCs, DACs, timers) in test equipment chassis. IC Role / Device Role / Timing Role: Low-skew inverting buffer distributing inverted clock edges to synchronous peripherals requiring phase-aligned sampling. Use Value: Maintains <9ns inter-output skew across all eight outputs, preserving setup/hold margins for 100MHz+ sampling clocks. | Use Scenario: Replacing obsolete 74LS240 in field-deployed medical imaging boards requiring extended lifecycle support. IC Role / Device Role / Timing Role: Pin-compatible drop-in upgrade delivering identical logic function with lower power and wider voltage tolerance. Use Value: Extends product service life without PCB redesign, reducing qualification cost and time-to-market for repair kits. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal inverting buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HC240PWRE4 | TSSOP-20 package (6.5mm × 6.4mm); same electrical specs, lower thermal resistance (RθJA = 131.8°C/W vs 113.4°C/W) | Better suited for high-density PCBs where footprint area is constrained but thermal dissipation is less critical | Select when board space is premium and reflow profile supports fine-pitch gull-wing leads |
| SN74HCT240NSRE4 | CMOS input thresholds matched to TTL levels (VIH = 2.0V min); identical pinout and drive capability | Preferred in mixed 5V TTL/CMOS systems where input noise immunity must match legacy TTL logic families | Choose when interfacing directly with 74LS/74ALS devices without level-shifting circuitry |
Compared with SN74HC240PWRE4 and SN74HCT240NSRE4, the SN74HC240NSRE4 offers optimal balance of mechanical compatibility with legacy SOP footprints, moderate thermal performance, and universal 2–6V operation - making it the default choice for retrofitting and general-purpose bus buffering where package height and layout reuse are priorities.
Availability
SN74HC240NSRE4 is available at Aetrix Electronics and suitable for industrial automation, test instrumentation, and embedded control applications requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant manufacturing.
Supply support for SN74HC240NSRE4 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 for industrial, automotive, and communications markets.
The SN74HC240NSRE4 belongs to TI's 74HC logic family, engineered for high-speed, low-power 3-state bus interfacing in memory, clock, and control subsystems - emphasizing reliability, wide voltage operation, and backward compatibility with legacy TTL designs.
FAQ
What is the maximum operating temperature range for SN74HC240NSRE4?
The SN74HC240NSRE4 is rated for operation from –40°C to +85°C ambient temperature, consistent with commercial-grade specifications for the SOP-20 package variant. This range supports deployment in industrial control cabinets, factory-floor instrumentation, and outdoor embedded gateways without forced cooling.
Does SN74HC240NSRE4 support non-inverted signal paths?
No - the SN74HC240NSRE4 provides only inverting logic: when OE is low, Y outputs are the logical inverse of A inputs. For non-inverting buffering, TI recommends SN74HC244NSRE4, which shares identical package, pinout, and electrical specs except for polarity.
Can SN74HC240NSRE4 drive a 50pF load at 6V with guaranteed timing?
Yes - the SN74HC240NSRE4 specifies tpd ≤25ns (max) at VCC = 6V and CL = 50pF, with typical value of 9ns. This meets timing budgets for 20MHz+ address strobes and ensures reliable operation under worst-case capacitive loading conditions.
Is SN74HC240NSRE4 pin-compatible with older 74LS240 devices?
Yes - the SN74HC240NSRE4 uses identical SOP-20 pinout and logic function as 74LS240, including dual 4-bit inverting buffers with independent OE controls. However, it requires no external pull-ups and draws significantly less current, simplifying board design.
What decoupling capacitance is recommended for SN74HC240NSRE4?
Texas Instruments specifies a minimum 0.1µF ceramic capacitor placed within 2mm of the VCC pin (pin 20) and GND (pin 10). For systems with high-frequency switching noise, paralleling with a 1µF tantalum or X7R MLCC improves broadband suppression across 10kHz–100MHz.
SN74HC240NSRE4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HC
- Package/Case:
- 20-SOIC (0.209", 5.30mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- Logic Type:
- Buffer, Inverting
- Number of Elements:
- 2
- Number of Bits per Element:
- 4
- Input Type:
- -
- Output Type:
- 3-State
- Current - Output High, Low:
- 7.8mA, 7.8mA
- Voltage - Supply:
- 2V ~ 6V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SO
SN74HC240NSRE4 FAQ
1.How can I place an order for SN74HC240NSRE4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74HC240NSRE4 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 SN74HC240NSRE4 reliable?
The price and inventory of SN74HC240NSRE4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74HC240NSRE4 is usually 5 days.
3.What payment methods are accepted for SN74HC240NSRE4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74HC240NSRE4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74HC240NSRE4?
SN74HC240NSRE4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74HC240NSRE4 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 SN74HC240NSRE4?
For technical support, including SN74HC240NSRE4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74HC240NSRE4 requirements.
6.How does Aetrix verify that SN74HC240NSRE4 is sourced from the original manufacturer or authorized distributors?
All SN74HC240NSRE4 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 SN74HC240NSRE4 meets industry standards.
7.What is the process for return or replacement of SN74HC240NSRE4?
All SN74HC240NSRE4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74HC240NSRE4, 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 SN74HC240NSRE4 part is unused and in its original packaging.
Return procedure for SN74HC240NSRE4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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