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Texas Instruments SN74BCT540ADW
- Part No.:
- SN74BCT540ADW
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74BCT540ADW.pdf
- Description:
- IC BUFFER INVERT 5.5V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,779
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Product details
Overview
SN74BCT540ADW from Texas Instruments is an octal buffer/driver with 3-state outputs, designed for bus line driving and memory address register buffering in 5-V TTL-compatible systems. It operates from 4.5 V to 5.5 V, features biCMOS technology for low ICCZ (3–6 mA), supports 128 mA sink per output, and uses a dual active-low 3-state enable (OE1/OE2) with data flow-through pinout.
For engineers reviewing the SN74BCT540ADW datasheet, SN74BCT540ADW pinout, SN74BCT540ADW application, or SN74BCT540ADW equivalent, this device is selected for high-drive, low-quiescent-current bus interfacing where input/output separation simplifies PCB layout and ESD robustness (2000-V HBM) meets industrial reliability requirements.
Technical Context
This device implements eight independent non-inverting buffers, each with P-N-P input structure to reduce DC loading on upstream logic. Its 3-state control uses a dual-input AND gate with active-low enables - either OE1 or OE2 high forces all eight Y outputs into high-impedance state.
BiCMOS design enables TTL-level input compatibility while delivering CMOS-like output drive strength and reduced power consumption during output disable (ICCZ ≤ 6 mA). The data flow-through pinout places all eight A inputs on one side and all eight Y outputs on the opposite side of the 20-pin SOIC (DW) package.
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 bus systems. |
| Output Sink Current | 128 mA per Y output - drives heavy capacitive loads or multiple TTL inputs without external buffering. |
| Propagation Delay | tPLH/tPHL = 2.0–6.9 ns at 5 V/50 pF - supports high-speed address/data bus timing in microprocessor systems. |
| 3-State Enable Time | tPZH/tPZL = 3.3–11.3 ns - enables fast bus arbitration and dynamic bus sharing in multiprocessor designs. |
| Input Clamp Current | –18 mA - protects against negative transients and allows safe handling of undershoot below GND. |
| ESD Rating | 2000-V HBM - exceeds JEDEC JESD22-A114A, supporting robust handling in manufacturing and field environments. |
| Package Thermal Impedance | θJA = 58°C/W (DW) - enables stable operation up to 70°C ambient without forced airflow in dense layouts. |
Pinout & Package
SN74BCT540ADW is housed in a 20-pin SOIC (DW) package, 7.5 mm wide, 12.83 mm long, with 1.27 mm pitch and maximum height of 2.65 mm. Pin 1 identifier located at top-left corner with beveled edge marking.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4, 5, 6, 7, 8 | A1–A8 Inputs | Non-inverting data inputs; P-N-P structure reduces DC loading on preceding logic stages. |
| 9 | GND | Ground reference for all internal circuitry and output stage return path. |
| 10 | VCC | Positive supply (4.5–5.5 V); powers both input and output stages. |
| 11, 12 | OE1, OE2 | Active-low 3-state enables; either high disables all Y outputs (high-Z). |
| 13–20 | Y1–Y8 Outputs | Buffered, non-inverting, totem-pole outputs capable of 128 mA sink current. |
Key Features
| Feature | Design Value |
|---|---|
| BiCMOS Process Technology | Reduces ICCZ to ≤6 mA in 3-state mode - cuts standby power by >50% vs. legacy bipolar BCT devices. |
| Data Flow-Through Pinout | Inputs (pins 1–8) and outputs (pins 13–20) on opposite sides - eliminates layer crossovers and eases routing on 2-layer PCBs. |
| Dual Active-Low 3-State Control | Independent OE1/OE2 pins allow partitioned bus control - e.g., split memory map addressing across two enable domains. |
| P-N-P Input Structure | Limits input current to ≤0.6 mA (IIL) - prevents excessive loading on CMOS or TTL drivers driving multiple SN74BCT540ADW inputs. |
| High ESD Robustness | 2000-V HBM rating - eliminates need for external transient protection in most industrial board-level applications. |
Applications
| Memory Address Buffering | System Bus Driver |
|---|---|
Use Scenario: Buffering 8-bit address lines between microcontroller and SRAM or EPROM in embedded control systems. IC Role / Device Role / Timing Role: Non-inverting level-shifting buffer with 3-state control enabling shared address bus access among multiple masters. Use Value: 128 mA sink capability drives 10+ TTL loads per line; 2–7 ns propagation delay preserves setup/hold timing margins at 10 MHz bus rates. |
Use Scenario: Driving a 5-V parallel data bus shared between CPU, DMA controller, and peripheral interface ICs. IC Role / Device Role / Timing Role: Bidirectional bus driver with fast 3-state enable/disable (≤11.3 ns) for glitch-free bus arbitration. Use Value: Dual OE inputs allow independent control of upper/lower byte segments; low ICCZ minimizes power during bus idle periods. |
| Industrial I/O Expansion | Legacy System Interface Adapter |
Use Scenario: Interfacing modern microcontrollers to legacy 5-V TTL peripherals (e.g., printers, sensors, displays) via parallel port expansion. IC Role / Device Role / Timing Role: Level-compatible buffer isolating MCU GPIOs from high-current peripheral loads. Use Value: P-N-P inputs tolerate slow-rising signals; 2000-V HBM withstands factory handling and field ESD events. |
Use Scenario: Replacing obsolete 74LS540 or 74ALS540 in repair or life-extension programs for aging test equipment and PLC modules. IC Role / Device Role / Timing Role: Pin-compatible drop-in upgrade offering higher drive, lower power, and improved ESD immunity. Use Value: Identical 20-pin SOIC-DW footprint and logic function; no PCB redesign required for direct replacement. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal buffer/driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LS540N | Lower drive (24 mA sink), higher ICCZ (30 mA), slower tPLH (15 ns), no HBM ESD rating. | Suitable only for low-speed, low-load legacy systems; not recommended for new designs or noisy industrial environments. | Choose SN74BCT540ADW when upgrading LS-based systems requiring higher speed, drive, or ESD resilience. |
| SN74ACT540PW | CMOS input (VIH = 2 V), 24 mA sink, 3-state but no dual OE; identical 20-pin TSSOP package. | Better for 3.3-V–5-V mixed-signal interfaces; lacks dual-enable flexibility and high-current drive needed for bus termination. | Select SN74BCT540ADW over SN74ACT540PW when driving heavy TTL loads or requiring independent OE partitioning. |
Compared with SN74LS540N and SN74ACT540PW, SN74BCT540ADW uniquely combines 128 mA sink strength, dual active-low 3-state control, and 2000-V HBM protection - making it the preferred choice for robust, high-drive 5-V bus interfacing where reliability and timing margin are critical.
Availability
SN74BCT540ADW is available at Aetrix Electronics and suitable for memory subsystems, industrial I/O expansion, legacy system upgrades, and embedded bus interface applications requiring stable component supply and long-term lifecycle support.
Supply support for SN74BCT540ADW 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 decades of heritage in industrial-grade logic families.
SN74BCT540ADW belongs to TI's BCT (Bipolar-CMOS Transistor) logic family, engineered for high-speed, high-drive 5-V bus interfacing in industrial, computing, and communications infrastructure.
FAQ
What is the operating voltage range for SN74BCT540ADW?
The SN74BCT540ADW operates from 4.5 V to 5.5 V. This range ensures full compatibility with standard 5-V TTL logic families and accommodates typical power supply tolerances in industrial and computing applications. Operation outside this range may cause functional failure or damage, as absolute maximum ratings specify –0.5 V to 7 V for VCC but functional behavior is guaranteed only within the recommended 4.5–5.5 V window.
How does the dual 3-state enable (OE1/OE2) work on SN74BCT540ADW?
The SN74BCT540ADW uses a 2-input AND gate with active-low logic for its 3-state control: if either OE1 or OE2 is high, all eight Y outputs enter high-impedance state. Both OE inputs must be low for outputs to actively drive. This architecture allows flexible bus segmentation - for example, OE1 can control Y1–Y4 while OE2 controls Y5–Y8 - without requiring external logic.
Is SN74BCT540ADW pin-compatible with older 74LS540 devices?
Yes, SN74BCT540ADW shares identical pinout and logic function with 74LS540 in the 20-pin SOIC (DW) package, enabling direct replacement in existing designs. However, SN74BCT540ADW delivers significantly higher output drive (128 mA vs. 24 mA), faster propagation (≤6.9 ns vs. ~15 ns), and lower ICCZ - providing performance and reliability upgrades without layout changes.
What is the maximum output sink current per channel for SN74BCT540ADW?
Each Y output of the SN74BCT540ADW supports up to 128 mA sink current under recommended operating conditions (VCC = 4.5 V, TA = 0–70°C). This rating is specified in the electrical characteristics table and enables direct driving of multiple TTL inputs, LED arrays, or bus termination networks without external amplification.
Does SN74BCT540ADW require external pull-up resistors on OE pins?
Yes - to ensure outputs remain in high-impedance state during power-up or power-down, OE1 and OE2 should each be tied to VCC through a pull-up resistor. TI recommends minimum resistance based on the driver's current-sinking capability; for reliable operation, 10 kΩ is commonly used and verified in application notes such as SCBA004 for slow/floating input implications.
SN74BCT540ADW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74BCT
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Bulk
- Product Status:
- Active
- Logic Type:
- Buffer, Inverting
- Number of Elements:
- 1
- Number of Bits per Element:
- 8
- 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
SN74BCT540ADW FAQ
1.How can I place an order for SN74BCT540ADW through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74BCT540ADW 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 SN74BCT540ADW reliable?
The price and inventory of SN74BCT540ADW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74BCT540ADW is usually 5 days.
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SN74BCT540ADW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74BCT540ADW 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 SN74BCT540ADW?
For technical support, including SN74BCT540ADW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74BCT540ADW requirements.
6.How does Aetrix verify that SN74BCT540ADW is sourced from the original manufacturer or authorized distributors?
All SN74BCT540ADW 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 SN74BCT540ADW meets industry standards.
7.What is the process for return or replacement of SN74BCT540ADW?
All SN74BCT540ADW units undergo pre-shipment inspection (PSI). If there is an issue with SN74BCT540ADW, 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 SN74BCT540ADW part is unused and in its original packaging.
Return procedure for SN74BCT540ADW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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