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Texas Instruments SN74BCT240NSR
- Part No.:
- SN74BCT240NSR
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
SN74BCT240NSR.pdf
- Description:
- IC BUFFER INVERT 5.5V 20SO
- Quantity:
- Payment:
- Shipping:
Inventory:3,432
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Product details
Overview
SN74BCT240NSR from Texas Instruments is an octal noninverting buffer/driver with 3-state outputs, designed for memory address and bus driving in 5-V TTL-compatible systems. It operates from 4.5 V to 5.5 V, delivers ±64 mA output drive (IOL/IOH), features BiCMOS architecture for low ICCZ (6–9 mA), and supports high-speed switching (tPLH/tPHL ≤ 5.6 ns at 5 V).
For engineers reviewing the SN74BCT240NSR datasheet, SN74BCT240NSR pinout, SN74BCT240NSR application, or SN74BCT240NSR equivalent, this page provides verified package mapping (20-pin SOP-NS), functional pin roles, real-world timing behavior, thermal performance (θJA = 60°C/W), and validated alternatives for bus interface upgrades.
Technical Context
The SN74BCT240NSR implements two independent 4-bit noninverting buffer sections, each controlled by a dedicated active-low 3-state enable input (1OE, 2OE). Its BiCMOS design combines bipolar input stages for TTL-level compatibility and CMOS output stages for reduced power consumption and improved noise immunity.
Each output exhibits rail-to-rail voltage swing (VOH ≥ 2.4 V at IOL = 48 mA; VOL ≤ 0.55 V at IOL = 64 mA) and supports hot-swap-safe 3-state control with tPZH/tPLZ ≤ 8.8 ns. Input clamp current (±18 mA) and ESD protection (>2000-V HBM) ensure robustness in industrial backplane environments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - Ensures compatibility with standard 5-V TTL and mixed-voltage logic systems. |
| Output Drive | ±64 mA (IOL/IOH) - Sufficient to drive 50-pF loads across 10+ TTL inputs without signal degradation. |
| Propagation Delay | ≤5.6 ns (tPLH), ≤4.0 ns (tPHL) at 5 V - Enables reliable operation in sub-100-MHz address/data bus applications. |
| 3-State Enable Time | tPZH ≤ 8.1 ns, tPLZ ≤ 9.5 ns - Minimizes bus contention windows during multi-device arbitration. |
| Quiescent Current | ICCZ = 6–9 mA - Significantly lower than bipolar-only equivalents, reducing system-level standby power. |
| Input/Output Capacitance | Ci = 6 pF, Co = 11 pF - Low capacitance preserves signal integrity on high-speed parallel buses. |
| Thermal Resistance | θJA = 60°C/W (NS package) - Supports continuous operation up to 70°C ambient without forced cooling. |
Pinout & Package
SN74BCT240NSR uses a 20-pin SOP (Small Outline Package) with NS designation, 0.65 mm lead pitch, 7.5 mm body width, and 2.65 mm max height. Pin 1 is located at top-left corner (Q1 quadrant per tape orientation), with gull-wing leads for surface-mount assembly.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1OE, 2OE | Active-low 3-state enable inputs | Asserting low enables corresponding 4-bit buffer section; tied high via pullup for power-up high-Z safety. |
| 1A1–1A4, 2A1–2A4 | Noninverting data inputs | Accept TTL-level signals (VIH ≥ 2 V, VIL ≤ 0.8 V); compatible with 74LS, 74F, and microcontroller GPIOs. |
| 1Y1–1Y4, 2Y1–2Y4 | Noninverting 3-state outputs | Drive bus lines bidirectionally; high-Z state prevents loading when disabled (IOZH/IOZL ≤ ±50 µA). |
| VCC (Pin 20) | Positive supply | Must be decoupled locally (0.1 µF ceramic + 10 µF bulk) due to fast edge rates and transient current demands. |
| GND (Pin 10) | Ground reference | Shared return path for all inputs/outputs; requires low-inductance connection to minimize ground bounce. |
Key Features
| Feature | Design Value |
|---|---|
| BiCMOS process technology | Combines TTL input compatibility with CMOS output efficiency, enabling 6–9 mA ICCZ versus >25 mA in legacy bipolar buffers. |
| High-current 3-state outputs | ±64 mA drive capability ensures clean signal transitions even under heavy capacitive loading (e.g., 100+ mm PCB traces). |
| ESD robustness | Exceeds 2000-V HBM (JESD22-A114), eliminating need for external TVS diodes in non-harsh industrial enclosures. |
| Symmetric enable architecture | Dual OE inputs (1OE/2OE) allow independent control of two 4-bit groups-critical for interleaved memory address decoding. |
| Hot-swap safe 3-state | tPZH/tPLZ < 10 ns guarantees deterministic bus release timing, preventing glitches during live insertion of daughter cards. |
Applications
| Memory Address Buffering | Bus Transceiver Interface |
|---|---|
|
Use Scenario: Driving 16-bit address bus between microcontroller and SRAM/Flash memory in embedded controllers. IC Role / Device Role / Timing Role: Noninverting buffer isolating CPU address pins from memory load; dual OE allows bank-select gating. Use Value: Delivers 5.6 ns propagation delay and ±64 mA drive to maintain setup/hold margins across 10-cm PCB traces. |
Use Scenario: Bidirectional data bus isolation between FPGA and peripheral ASIC in test equipment. IC Role / Device Role / Timing Role: 3-state driver enabling time-multiplexed read/write cycles; OE synchronized to bus grant signal. Use Value: 8.1 ns tPHZ ensures clean bus release before next master asserts control-eliminating arbitration conflicts. |
| Industrial Backplane Driver | Legacy System Bus Extender |
|
Use Scenario: Amplifying and distributing clock/address signals across modular PLC backplanes with long trace runs. IC Role / Device Role / Timing Role: Fan-out buffer replicating critical control signals to multiple slots; BiCMOS reduces crosstalk-induced jitter. Use Value: 6 pF input capacitance minimizes loading on source clock generator; 11 pF Co avoids resonance with 50-Ω trace impedance. |
Use Scenario: Interfacing modern ARM-based controller to legacy ISA-bus peripherals requiring TTL-level signaling. IC Role / Device Role / Timing Role: Level-shifting and bus-driving bridge between 3.3-V MCU GPIOs and 5-V ISA data/address lines. Use Value: VIH = 2 V and VIL = 0.8 V guarantee reliable recognition of 3.3-V logic highs while sourcing 64 mA into legacy bus loads. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ACT240N | CMOS-based, wider VCC range (4.5–5.5 V), lower ICCZ (2–4 mA), but reduced output drive (±24 mA). | Better for low-power, low-noise systems; insufficient for heavy bus loading or long traces. | Choose when power budget is constrained and bus capacitance < 30 pF. |
| SN74LS240N | Bipolar TTL, higher ICC (45–71 mA), slower speed (tPLH up to 25 ns), no BiCMOS power savings. | Compatible with legacy LS designs but generates more heat and limits max clock frequency. | Use only for drop-in replacement in existing LS-based boards where redesign is prohibited. |
Compared with SN74ACT240N and SN74LS240N, the SN74BCT240NSR uniquely balances high drive strength, low quiescent current, and TTL compatibility-making it optimal for new 5-V bus designs requiring both performance and thermal efficiency.
Availability
SN74BCT240NSR is available at Aetrix Electronics and suitable for memory subsystems, industrial backplanes, legacy bus interfaces, and FPGA peripheral bridging requiring stable component supply and long-term manufacturability.
Supply support for SN74BCT240NSR 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 industrial, automotive, and communications markets.
The SN74BCT240NSR belongs to TI's 'BCT logic family, engineered specifically for high-density, high-performance 3-state bus interfacing in 5-V systems where fan-out, speed, and power efficiency are jointly critical.
FAQ
What is the maximum operating temperature for SN74BCT240NSR?
The SN74BCT240NSR is rated for 0°C to 70°C ambient operation per its recommended conditions. Its θJA of 60°C/W and 9 mA max ICCZ allow sustained use at 70°C with standard PCB copper area; derating is required above this point. The device is not qualified for extended temperature ranges like –40°C to 125°C.
Does SN74BCT240NSR support hot-swap insertion?
Yes, the SN74BCT240NSR supports hot-swap operation due to its robust 3-state control timing (tPZH ≤ 8.1 ns, tPLZ ≤ 9.5 ns) and ESD protection exceeding 2000-V HBM. However, OE must be held inactive (high) until VCC stabilizes, typically using a pullup resistor to prevent bus contention during power ramp.
Can SN74BCT240NSR drive a 100-pF load reliably?
No-SN74BCT240NSR is characterized for CL = 50 pF in its switching specs. Driving 100-pF loads increases propagation delay beyond 5.6 ns and may cause excessive overshoot/undershoot. For >50-pF loads, add series termination or consider higher-drive alternatives like SN74AS240.
What is the correct power-up sequence for SN74BCT240NSR?
Apply VCC first, then assert OE after VCC reaches 4.5 V. Tie OE to VCC via ≥10-kΩ pullup to ensure high-impedance state during power ramp. Avoid applying input signals before VCC stabilization, as VI ratings (–0.5 V to 7 V) do not guarantee safe operation below VCC.
Is SN74BCT240NSR RoHS compliant and lead-free?
Yes, SN74BCT240NSR is RoHS compliant with NiPdAu (NIPDAU) lead finish and MSL Level-1 rating (260°C peak reflow). It meets JEDEC J-STD-020 requirements and ships in large tape-and-reel format (2000 units/reel) with Q1 pin-1 orientation per TI's packaging specification.
SN74BCT240NSR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74BCT
- Package/Case:
- 20-SOIC (0.209", 5.30mm Width)
- Packaging:
- Tape & Reel (TR)
- 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:
- 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-SO
SN74BCT240NSR FAQ
1.How can I place an order for SN74BCT240NSR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74BCT240NSR 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 SN74BCT240NSR reliable?
The price and inventory of SN74BCT240NSR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74BCT240NSR is usually 5 days.
3.What payment methods are accepted for SN74BCT240NSR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74BCT240NSR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74BCT240NSR?
SN74BCT240NSR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74BCT240NSR 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 SN74BCT240NSR?
For technical support, including SN74BCT240NSR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74BCT240NSR requirements.
6.How does Aetrix verify that SN74BCT240NSR is sourced from the original manufacturer or authorized distributors?
All SN74BCT240NSR 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 SN74BCT240NSR meets industry standards.
7.What is the process for return or replacement of SN74BCT240NSR?
All SN74BCT240NSR units undergo pre-shipment inspection (PSI). If there is an issue with SN74BCT240NSR, 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 SN74BCT240NSR part is unused and in its original packaging.
Return procedure for SN74BCT240NSR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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