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Texas Instruments SN74BCT2240DW
- Part No.:
- SN74BCT2240DW
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74BCT2240DW.pdf
- Description:
- IC BUFFER INVERT 5.5V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,975
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Product details
Overview
SN74BCT2240DW from Texas Instruments is an octal noninverting buffer/line 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, features integrated 33-Ω series output resistors, supports ±12 mA output drive, and delivers propagation delays as low as 0.5 ns (tPLH/tPHL) at 5 V.
For engineers reviewing the SN74BCT2240DW datasheet, SN74BCT2240DW pinout, SN74BCT2240DW application, or SN74BCT2240DW equivalent, key selection criteria include 3-state bus interface capability, BiCMOS low ICCZ quiescent current (6–8 mA), symmetrical active-low OE control per 4-bit section, and SOIC-20 package thermal performance (θJA = 58°C/W).
Technical Context
This device implements two independent 4-bit noninverting buffer sections, each with dedicated active-low output-enable (OE) inputs. Each output is internally series-terminated with a 33-Ω resistor to suppress transmission-line overshoot/undershoot without external components.
It uses BiCMOS technology to combine bipolar input stages for high speed and CMOS output stages for low power, achieving fan-out >30 into TTL loads while maintaining compatibility with standard 5-V TTL logic thresholds (VIH = 2 V, VIL = 0.8 V).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - Ensures robust operation across industrial 5-V rail tolerances. |
| Output Drive | ±12 mA - Sufficient to directly drive 50-pF bus loads with fast edge rates. |
| Propagation Delay | 0.5–6.3 ns (tPLH/tPHL) - Enables reliable timing in high-speed address/data paths up to ~150 MHz. |
| ICCZ Quiescent Current | 6–8 mA - Significantly lower than legacy TTL equivalents, reducing system standby power. |
| Output Series Resistance | 33 Ω - Integrated termination eliminates need for external resistors on PCB traces. |
| Input Thresholds | VIH = 2 V, VIL = 0.8 V - Fully compatible with standard TTL logic families without level shifting. |
| Thermal Resistance | θJA = 58°C/W (SOIC-DW) - Supports continuous operation at ambient up to 70°C with minimal heatsinking. |
Pinout & Package
SN74BCT2240DW is housed in a 20-pin SOIC (DW) package with 0.300-inch body width and standard JEDEC MO-150 footprint. Pin spacing is 0.050 inch (1.27 mm), and total package dimensions are 12.80 mm × 7.50 mm × 2.35 mm (L × W × H).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1OE, 2OE | Active-low output-enable control | Independent enables for each 4-bit section; must be pulled high via resistor during power-up/down to ensure Hi-Z state. |
| 1A1–1A4, 2A1–2A4 | Noninverting data inputs | Eight TTL-compatible inputs grouped into two 4-bit banks; unused inputs must be tied to VCC or GND. |
| 1Y1–1Y4, 2Y1–2Y4 | 3-state buffered outputs | Octal outputs with built-in 33-Ω series resistance; capable of sourcing/sinking ±12 mA in active state. |
| VCC (Pin 20) | Positive supply | 4.5–5.5 V nominal; decoupling capacitor required near pin for noise suppression. |
| GND (Pin 10) | Ground reference | Common return path for all I/O and supply currents; low-inductance connection critical for signal integrity. |
Key Features
| Feature | Design Value |
|---|---|
| BiCMOS architecture | Combines bipolar speed and CMOS efficiency to achieve sub-7 ns propagation delay with <8 mA ICCZ. |
| Integrated 33-Ω output series resistors | Eliminates need for external termination resistors on PCB, simplifying layout and reducing BOM count. |
| Dual independent 4-bit sections | Enables flexible partitioning of address/data buses-e.g., low/high nibble control or separate peripheral enable domains. |
| TTL-compatible input thresholds | Accepts standard 5-V TTL logic levels (VIH ≥ 2 V, VIL ≤ 0.8 V), enabling direct interfacing with legacy controllers. |
| 3-state bus-driving capability | Supports multi-drop bus architectures by allowing outputs to enter high-impedance state when disabled via OE. |
Applications
| Memory Address Buffering | System Bus Interface |
|---|---|
|
Use Scenario: Driving 16-bit address lines from a microcontroller to multiple SRAM or ROM chips on a shared bus. IC Role / Device Role / Timing Role: Noninverting octal buffer providing isolation, fan-out expansion, and controlled 3-state release timing. Use Value: Prevents address contention during bus arbitration using independent OE controls; 33-Ω outputs reduce ringing on long traces. |
Use Scenario: Interfacing a CPU's data bus to peripheral devices with staggered enable timing requirements. IC Role / Device Role / Timing Role: Bidirectional-capable 3-state line driver managing data flow direction and timing alignment. Use Value: Enables clean bus sharing without external transceivers; low ICCZ minimizes power draw during idle cycles. |
| Legacy TTL System Upgrade | Industrial Control Backplane |
|
Use Scenario: Replacing obsolete 74LS240 buffers in aging industrial controllers requiring higher speed and lower power. IC Role / Device Role / Timing Role: Pin-compatible functional upgrade delivering faster tPLH/tPHL and reduced heat generation. Use Value: Maintains existing PCB layout while improving timing margin and thermal performance in enclosed enclosures. |
Use Scenario: Distributing clock or strobe signals across a DIN-rail mounted PLC backplane with multiple I/O modules. IC Role / Device Role / Timing Role: Low-skew buffer ensuring synchronized enable timing across distributed nodes. Use Value: Built-in 33-Ω resistors suppress reflections on 10+ cm backplane traces, preserving signal integrity at 20+ MHz. |
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 |
|---|---|---|---|
| SN74BCT2241DW | Inverting outputs instead of noninverting; identical pinout, voltage range, and drive strength. | Required where logic inversion is needed in the signal path (e.g., active-high to active-low conversion). | Select SN74BCT2241DW only if inversion is functionally necessary; otherwise SN74BCT2240DW preserves signal polarity. |
| SN74ACT240N | Advanced CMOS (ACT) process; lower ICCZ (~2 mA), but no integrated 33-Ω resistors and stricter VIH/VIL (2 V/0.8 V same, but less noise margin). | Suitable for new designs prioritizing ultra-low static power, but requires external termination and careful noise management. | Choose SN74ACT240N for lowest power in noise-controlled environments; SN74BCT2240DW preferred for robustness on noisy or long-trace buses. |
Compared with SN74BCT2240DW, SN74BCT2241DW provides identical timing and drive but inverted logic, while SN74ACT240N trades integrated termination and BiCMOS noise immunity for lower quiescent current-making SN74BCT2240DW optimal for legacy bus upgrades and electrically demanding industrial layouts.
Availability
SN74BCT2240DW is available at Aetrix Electronics and suitable for memory address buffering, system bus interfacing, legacy TTL upgrades, and industrial backplane signal distribution requiring stable component supply and long-term industrial lifecycle support.
Supply support for SN74BCT2240DW 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 experience in industrial-grade logic families.
The SN74BCT2240DW belongs to TI's BCT (Bipolar-CMOS Transistor) logic family, engineered specifically for high-speed, low-power 3-state bus interface applications in memory and computing subsystems.
FAQ
What is the recommended power-up sequence for SN74BCT2240DW?
During power-up, tie both 1OE and 2OE pins to VCC through a pullup resistor (minimum value determined by driver sink capability) to force outputs into high-impedance state before valid inputs are applied. This prevents bus contention. The SN74BCT2240DW datasheet specifies that OE should not float, and the resistor ensures deterministic behavior before system initialization completes.
Does SN74BCT2240DW require external series resistors on its outputs?
No. The SN74BCT2240DW integrates 33-Ω series resistors on all eight outputs, explicitly designed to dampen overshoot and undershoot on transmission lines. This eliminates the need for discrete 33-Ω resistors in most PCB layouts, reducing component count and layout complexity while maintaining signal integrity on typical 50-pF bus loads.
Can SN74BCT2240DW drive standard TTL loads directly?
Yes. The SN74BCT2240DW is fully TTL-compatible: it accepts standard TTL input thresholds (VIH ≥ 2 V, VIL ≤ 0.8 V) and delivers ±12 mA output drive-exceeding the −0.4 mA/1.6 mA requirements of standard TTL. Its BiCMOS design ensures fan-out >30 into TTL loads without external buffering.
What is the maximum operating temperature for SN74BCT2240DW?
The SN74BCT2240DW is rated for operation from 0°C to +70°C ambient temperature. Its SOIC-DW package has a junction-to-ambient thermal resistance (θJA) of 58°C/W, meaning it can sustain continuous operation at 70°C ambient with appropriate board copper area and airflow, assuming typical power dissipation of ~300 mW under full load.
How does SN74BCT2240DW differ from SN74LS240 in practical use?
The SN74BCT2240DW replaces SN74LS240 with significantly faster propagation delays (0.5–6.3 ns vs. 15–25 ns), lower ICCZ (6–8 mA vs. ~25 mA), integrated 33-Ω termination, and improved noise immunity due to BiCMOS input structure. Unlike the LS version, SN74BCT2240DW maintains full pin compatibility while enabling higher clock rates and lower system power in legacy upgrades.
SN74BCT2240DW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74BCT
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tube
- 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:
- 12mA, 12mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
SN74BCT2240DW FAQ
1.How can I place an order for SN74BCT2240DW through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74BCT2240DW 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 SN74BCT2240DW reliable?
The price and inventory of SN74BCT2240DW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74BCT2240DW is usually 5 days.
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SN74BCT2240DW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74BCT2240DW 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 SN74BCT2240DW?
For technical support, including SN74BCT2240DW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74BCT2240DW requirements.
6.How does Aetrix verify that SN74BCT2240DW is sourced from the original manufacturer or authorized distributors?
All SN74BCT2240DW 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 SN74BCT2240DW meets industry standards.
7.What is the process for return or replacement of SN74BCT2240DW?
All SN74BCT2240DW units undergo pre-shipment inspection (PSI). If there is an issue with SN74BCT2240DW, 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 SN74BCT2240DW part is unused and in its original packaging.
Return procedure for SN74BCT2240DW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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