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Texas Instruments SN74HC240DW
- Part No.:
- SN74HC240DW
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74HC240DW.pdf
- Description:
- IC BUFFER INVERT 6V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,252
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Product details
Overview
SN74HC240DW 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, exhibits 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 SN74HC240DW datasheet, SN74HC240DW pinout, SN74HC240DW application, or SN74HC240DW equivalent, key selection criteria include its dual 4-bit inverting architecture, independent OE controls per group, SOIC-20 package compatibility, and verified 3-state bus-driving capability under 5V TTL-load conditions.
Technical Context
The SN74HC240DW 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, all eight outputs enter high-impedance state - enabling bidirectional bus control without external logic.
It uses silicon-gate CMOS technology for rail-to-rail input compatibility, low static current (≤1µA), and noise immunity across its full 2V–6V supply range. Its switching characteristics are specified at CL = 50 pF and TA = 25°C, with tpd = 9ns (typ) at VCC = 4.5V, supporting reliable timing in synchronous memory and clock distribution circuits.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 2V to 6V - supports direct interface with 3.3V and 5V logic families without level shifters. |
| Output Drive Capability | ±6mA at 5V - drives up to 15 LSTTL loads, sufficient for legacy bus termination and address buffering. |
| Propagation Delay (tpd) | 9ns typical at VCC = 4.5V, CL = 50 pF - enables operation in sub-100MHz address/data paths. |
| Quiescent Current (ICC) | 80µA max - ensures minimal power impact in always-on system management functions. |
| Input Leakage Current | 1µA max - prevents unintended logic transitions when inputs are tied to VCC/GND for unused pins. |
| 3-State Enable/Disable Time | ten = 25ns, tdis = 32ns (max at VCC = 6V) - guarantees clean bus release and acquisition during multiplexed access. |
Pinout & Package
SN74HC240DW is housed in a 20-pin SOIC (DW) package measuring 12.80mm × 10.3mm (body: 12.80mm × 7.50mm), RoHS-compliant with NIPDAU lead finish and MSL Level-1 rating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | 1OE, 2OE | Active-low enable inputs controlling Group 1 (pins 2–9) and Group 2 (pins 11–18) independently. |
| 2, 4, 6, 8, 11, 13, 15, 17 | 1A1–1A4, 2A1–2A4 | Inverting input terminals - logic inversion occurs before 3-state output stage. |
| 3, 5, 7, 9, 12, 14, 16, 18 | 1Y1–1Y4, 2Y1–2Y4 | Inverting 3-state outputs - high-impedance when corresponding OE is high. |
| 10 | GND | Ground reference for all internal circuitry and output drivers. |
| 20 | VCC | Positive supply rail - must be bypassed with 0.1µF ceramic capacitor near pin for stable switching. |
Key Features
| Feature | Design Value |
|---|---|
| Inverting 3-state buffers | Two independent 4-bit groups allow selective bus isolation while maintaining signal polarity inversion for timing alignment. |
| Wide supply voltage range | 2V–6V operation enables interoperability across mixed-voltage systems including 3.3V microcontrollers and 5V peripherals. |
| Low power consumption | 80µA max ICC eliminates thermal concerns in high-channel-count PCB layouts and battery-backed subsystems. |
| High noise immunity | VIH/VIL thresholds scale with VCC (e.g., VIH = 3.15V at 4.5V), ensuring robust operation in electrically noisy industrial environments. |
| Bus-compatible output structure | Outputs meet LSTTL drive specs and tolerate floating-bus conditions - critical for hot-swap-capable backplane interfaces. |
Applications
| Memory Address Buffering | Industrial Bus Transceiver |
|---|---|
|
Use Scenario: Driving 20-bit address lines from a microcontroller to multiple SRAM chips on a shared bus. IC Role / Device Role / Timing Role: Inverting 3-state buffer isolating CPU address outputs during DMA cycles and enabling peripheral address decoding. Use Value: Prevents bus contention during memory arbitration while maintaining deterministic 9ns propagation delay for cycle timing compliance. |
Use Scenario: Interfacing a PLC's CPU module with field I/O expansion racks over a parallel control bus. IC Role / Device Role / Timing Role: Bidirectional bus driver managing direction control via OE signals synchronized to master clock edges. Use Value: Enables deterministic turnaround time (tdis/ten ≤32ns) for half-duplex command-response protocols in real-time automation. |
| Legacy System Logic Translation | Test Equipment Signal Conditioning |
|
Use Scenario: Converting 3.3V FPGA address outputs to drive 5V EPROMs in retro-computing hardware restoration. IC Role / Device Role / Timing Role: Level-shifting inverter buffer providing voltage translation and fanout amplification without external resistors. Use Value: Eliminates need for discrete level-shifters while preserving setup/hold timing margins due to matched tpd across VCC range. |
Use Scenario: Isolating DUT address/data lines from automated test equipment during functional pattern generation. IC Role / Device Role / Timing Role: 3-state gate controlling signal flow between tester channel and device-under-test during vector loading. Use Value: Guarantees <1µA leakage in high-Z state, preventing false triggering or loading of sensitive analog measurement nodes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal inverting buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HC240DWR | Same SOIC-20 footprint and electrical specs; active production status vs. SN74HC240DW's obsolete status. | Identical functional behavior and pinout; suitable for new designs requiring long-term supply continuity. | Select SN74HC240DWR for volume production where TI's current-revision SOIC packaging and full lifecycle support are required. |
| SN74HCT240N | TTL-compatible input thresholds (VIH = 2V min), higher ICC (≤400µA), same 3-state architecture and pinout. | Better suited for mixed 5V TTL/CMOS systems where input noise margin must match legacy TTL logic families. | Choose SN74HCT240N when interfacing with older 5V TTL devices where HC-series input thresholds may cause marginal recognition. |
Compared with SN74HC240DW, SN74HC240DWR offers identical performance with guaranteed long-term availability, while SN74HCT240N trades lower power for enhanced TTL input compatibility - making the former ideal for new designs and the latter for legacy system integration.
Availability
SN74HC240DW is available at Aetrix Electronics and suitable for industrial control, test equipment, and legacy system repair requiring stable component supply despite its obsolete status - with traceable stock and documented revision history.
Supply support for SN74HC240DW 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 50 years of innovation in high-reliability logic ICs.
The SN74HC240DW belongs to TI's 74HC logic family, engineered for high-speed, low-power 3-state bus interfacing in memory, clock, and control applications across industrial and computing platforms.
FAQ
What is the operating temperature range for SN74HC240DW?
The SN74HC240DW is rated for operation from –40°C to +85°C ambient temperature. This industrial-grade range supports deployment in programmable logic controllers, motor drives, and factory automation equipment where extended thermal stability is required. The SOIC package's thermal resistance (RθJA = 109.1°C/W) ensures safe junction temperatures under typical load conditions within this envelope.
Does SN74HC240DW support non-inverting operation?
No, SN74HC240DW provides only inverting logic function: when OE is low, Y outputs are the logical complement of A inputs. It does not include non-inverting paths or configuration options. For non-inverting 3-state buffering, designers must select alternatives such as SN74HC244DW or implement external inversion using discrete gates.
Can SN74HC240DW drive standard 50Ω transmission lines?
SN74HC240DW is not designed for 50Ω line driving. Its ±6mA output drive at 5V corresponds to ~830Ω effective impedance under loaded conditions - optimized for LSTTL fanout and short PCB traces, not RF or high-speed serial links. For 50Ω termination, use purpose-built line drivers like SN65LVDS1 or DS90LV047A.
What is the maximum capacitive load SN74HC240DW can drive reliably?
SN74HC240DW switching characteristics are characterized at CL = 50 pF and CL = 150 pF. At 150 pF and VCC = 6V, tpd increases to 38ns (max) and tt to 45ns (max). Driving >150 pF risks timing violations and increased dynamic power; for heavier loads, add series termination or buffer stages.
Is SN74HC240DW pin-compatible with SN74LS240?
Yes, SN74HC240DW shares identical pinout and function mapping with SN74LS240, including dual 4-bit inverting 3-state architecture and OE placement. However, voltage thresholds, drive strength, and timing differ significantly - direct substitution requires verification of input compatibility, timing margins, and power delivery in the target system.
SN74HC240DW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HC
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Bulk
- 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:
- 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-SOIC
SN74HC240DW FAQ
1.How can I place an order for SN74HC240DW through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74HC240DW 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 SN74HC240DW reliable?
The price and inventory of SN74HC240DW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74HC240DW is usually 5 days.
3.What payment methods are accepted for SN74HC240DW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74HC240DW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74HC240DW?
SN74HC240DW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74HC240DW 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 SN74HC240DW?
For technical support, including SN74HC240DW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74HC240DW requirements.
6.How does Aetrix verify that SN74HC240DW is sourced from the original manufacturer or authorized distributors?
All SN74HC240DW 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 SN74HC240DW meets industry standards.
7.What is the process for return or replacement of SN74HC240DW?
All SN74HC240DW units undergo pre-shipment inspection (PSI). If there is an issue with SN74HC240DW, 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 SN74HC240DW part is unused and in its original packaging.
Return procedure for SN74HC240DW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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