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Texas Instruments SN74F240DWR
- Part No.:
- SN74F240DWR
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74F240DWR.pdf
- Description:
- IC BUFFER INVERT 5.5V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,645
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Product details
Overview
SN74F240DWR from Texas Instruments is an octal noninverting buffer/driver with 3-state outputs, designed for memory address driving and bus interfacing in TTL-compatible systems. It features two independent 4-bit sections, each with active-low output-enable (OE) control, 5 V supply operation, and SOIC-20 package. It supports high-speed data routing in industrial control backplanes and legacy computing address buses.
For engineers reviewing the SN74F240DWR datasheet, SN74F240DWR pinout, SN74F240DWR application, or SN74F240DWR equivalent, key selection criteria include 3-state bus drive capability, propagation delay under 8 ns, output current up to ±64 mA, and compatibility with standard 5 V TTL logic families and PCB layouts using SOIC-20 footprints.
Technical Context
The SN74F240DWR implements dual 4-bit noninverting buffers with symmetrical active-low OE inputs per section-1OE controls Y1–Y4, 2OE controls Y1'–Y4'. Each output transitions to high-impedance when its OE is high, enabling bidirectional bus sharing without external logic.
Its F-series TTL architecture delivers guaranteed switching performance at 5 V across 0°C to 70°C, with tPLH/tPHL ≤ 8 ns and tPZL/tPLZ ≤ 10 ns into 50 pF loads. Input thresholds (VIH = 2 V, VIL = 0.8 V) and output drive strength (IOL = 64 mA, IOH = –15 mA) are fully specified for interoperability with legacy 74F, 74LS, and 74AS logic.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - ensures stable operation across standard TTL power rail tolerances |
| Propagation Delay | tPLH/tPHL ≤ 8 ns @ 5 V, CL = 50 pF - enables reliable timing in 20–25 MHz address/data strobe paths |
| Output Drive | IOL = 64 mA, IOH = –15 mA - drives heavy capacitive loads (e.g., >10 TTL inputs or 100+ pF traces) |
| 3-State Leakage | IOZL/IOZH ≤ ±50 µA @ 5.5 V - minimizes bus contention current during high-Z state |
| Input Thresholds | VIH = 2.0 V, VIL = 0.8 V - guarantees noise margin ≥ 0.4 V in mixed-logic systems |
| Operating Temperature | 0°C to 70°C - qualified for commercial-grade embedded and industrial control environments |
Pinout & Package
SN74F240DWR uses a 20-pin SOIC (DW) package, 7.5 mm wide, 2.65 mm max height, with 1.27 mm pitch and RoHS-compliant NiPdAu lead finish. Pin 1 is located in Quadrant Q1 per tape-and-reel orientation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | 1OE, 2OE | Active-low output-enable inputs - independently disable Y1–Y4 and Y1'–Y4' groups |
| 2–5, 13–16 | 1A1–1A4, 2A1–2A4 | Data inputs - routed directly to corresponding outputs when OE is low |
| 6–9, 11–14 | 1Y1–1Y4, 2Y1–2Y4 | 3-state buffered outputs - high-impedance when OE is high; otherwise noninverting pass-through |
| 10 | GND | Ground reference - must be low-impedance connection to minimize switching noise |
| 20 | VCC | Positive supply - decoupling capacitor (0.1 µF) required adjacent to pin |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent 4-bit sections | Enables split-bus control - e.g., upper/lower byte addressing without inter-section timing skew |
| 3-State outputs with symmetrical OE | Eliminates need for external enable logic when sharing data/address buses among multiple drivers |
| High sink/source current (64 mA/–15 mA) | Drives long traces, multiple TTL loads, or termination resistors without external buffers |
| Guaranteed AC specs over full temp range | Ensures deterministic timing in temperature-varying industrial enclosures without derating |
| SOIC-20 RoHS-compliant packaging | Supports automated SMT assembly and reflow profiles (MSL Level-1, 260°C peak) |
Applications
| Memory Address Buffering | Legacy Bus Transceiver Interface |
|---|---|
Use Scenario: Driving 16-bit address lines from a microprocessor to multiple memory ICs on a shared bus. IC Role / Device Role / Timing Role: Noninverting 3-state buffer isolating CPU address outputs from memory decode logic and DRAM address pins. Use Value: Prevents bus contention during DMA cycles by disabling outputs via OE while preserving signal integrity at 20+ MHz edge rates. | Use Scenario: Interfacing between ISA-style peripheral cards and motherboard address/data buses. IC Role / Device Role / Timing Role: Bidirectional bus driver enabling peripheral-to-CPU address handshaking with controlled enable timing. Use Value: Matches TTL voltage thresholds and drive strength required by PC/AT-era bus specifications without level-shifting. |
| Industrial Backplane Signal Conditioning | EPROM Programming Adapter |
Use Scenario: Strengthening address signals distributed across a 100 mm backplane with >50 pF trace capacitance. IC Role / Device Role / Timing Role: Low-skew buffer compensating for trace loss and maintaining setup/hold margins for synchronous peripherals. Use Value: Delivers 64 mA sink current to overcome capacitive loading, ensuring clean edges at bus clock edges up to 25 MHz. | Use Scenario: Isolating programmer I/O from EPROM VPP and address pins during write/verify cycles. IC Role / Device Role / Timing Role: Controlled-enable buffer preventing accidental address changes during high-voltage programming pulses. Use Value: High-impedance state blocks leakage paths during VPP = 21 V, protecting programmer logic from latch-up or overstress. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal 3-state buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74F244DWR | Noninverting octal buffer with separate OE per 4-bit group - identical pinout and AC specs | No functional difference; SN74F244 is functionally identical to SN74F240 in noninverting configuration | Select SN74F244DWR if sourcing flexibility is prioritized - same footprint, identical timing, widely stocked |
| SN74ACT240DBR | CMOS version with 5 V tolerant inputs, lower ICC (20 µA), higher noise immunity (VIH = 3.5 V), but slower tPLH (9.5 ns) | Better for mixed-voltage systems requiring 3.3 V logic interfacing; unsuitable where strict F-series timing is mandated | Choose SN74ACT240DBR only when upgrading from TTL to ACT for power savings and noise margin - not a drop-in replacement due to timing and drive differences |
Compared with SN74F240DWR, SN74F244DWR offers identical functionality and pin compatibility for direct substitution, while SN74ACT240DBR trades raw speed for CMOS advantages - making it suitable only in redesigned systems where timing budgets allow 1.5 ns added delay and input threshold shifts are acceptable.
Availability
SN74F240DWR is available at Aetrix Electronics and suitable for industrial backplane buffering, legacy computer system repair, and EPROM programming adapter designs requiring stable component supply and long-term obsolescence management.
Supply support for SN74F240DWR 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 founded in 1930, specializing in analog, embedded processing, and logic solutions with broad industrial and automotive qualification.
The SN74F240DWR belongs to TI's 74F family of fast TTL logic devices, engineered for high-speed memory and bus interface applications in commercial-temperature embedded systems.
FAQ
What is the maximum output current rating for SN74F240DWR at VCC = 5 V?
The SN74F240DWR supports a low-level output current (IOL) of 64 mA and a high-level output current (IOH) of –15 mA at VCC = 5 V, as specified in the recommended operating conditions table. These values ensure robust drive capability into heavily loaded TTL buses or long PCB traces without signal degradation. The SN74F240DWR maintains these ratings across its full 0°C to 70°C operating range.
Does SN74F240DWR support hot-swap or live-insertion on a powered bus?
No, SN74F240DWR is not rated for hot-swap operation. Its absolute maximum ratings specify that output voltages must remain within –0.5 V to 5.5 V when disabled, and applying voltage to outputs before VCC is stabilized risks latch-up or damage. For live-insertion, external protection circuitry or dedicated hot-swap buffers are required. The SN74F240DWR design assumes power sequencing compliance per standard TTL practices.
Can SN74F240DWR be used with 3.3 V logic inputs?
SN74F240DWR inputs are TTL-compatible with VIH = 2.0 V minimum, so 3.3 V logic outputs meet the high-level threshold and will register correctly. However, its VCC must remain at 5 V to guarantee output swing and drive strength. Do not operate SN74F240DWR with VCC = 3.3 V - it is not characterized for sub-4.5 V supply and may fail to meet timing or drive specs.
What is the pin 1 marking and orientation for SN74F240DWR in tape-and-reel packaging?
SN74F240DWR uses SOIC-20 (DW) packaging with pin 1 located in Quadrant Q1 per TI's tape-and-reel specification. The device marking "F240" appears on the top surface near pin 1, and the carrier tape is oriented so that sprocket holes align with Q1–Q2. This matches JEDEC MS-013 and ensures correct automated placement during SMT assembly.
How does the 3-state enable behavior work on SN74F240DWR?
SN74F240DWR has two active-low output-enable inputs: 1OE (pin 1) controls Y1–Y4, and 2OE (pin 19) controls Y1'–Y4'. When either OE is low, its associated four outputs pass A-inputs to Y-outputs noninvertingly. When OE is high, those outputs enter high-impedance state - electrically disconnected from the bus. This allows independent control of two 4-bit segments, critical for byte-wide bus arbitration.
SN74F240DWR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74F
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- 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:
- 15mA, 64mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
SN74F240DWR FAQ
1.How can I place an order for SN74F240DWR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74F240DWR 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 SN74F240DWR reliable?
The price and inventory of SN74F240DWR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74F240DWR is usually 5 days.
3.What payment methods are accepted for SN74F240DWR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74F240DWR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74F240DWR?
SN74F240DWR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74F240DWR 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 SN74F240DWR?
For technical support, including SN74F240DWR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74F240DWR requirements.
6.How does Aetrix verify that SN74F240DWR is sourced from the original manufacturer or authorized distributors?
All SN74F240DWR 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 SN74F240DWR meets industry standards.
7.What is the process for return or replacement of SN74F240DWR?
All SN74F240DWR units undergo pre-shipment inspection (PSI). If there is an issue with SN74F240DWR, 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 SN74F240DWR part is unused and in its original packaging.
Return procedure for SN74F240DWR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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