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Texas Instruments SN74BCT2245DW
- Part No.:
- SN74BCT2245DW
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74BCT2245DW.pdf
- Description:
- IC TXRX NON-INVERT 5.5V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,090
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Product details
Overview
SN74BCT2245DW from Texas Instruments is an octal transceiver and line/MOS driver with 3-state outputs, designed for bidirectional asynchronous data bus communication between A and B buses. It operates at 4.5 V to 5.5 V, supports direction control via DIR input and output enable via OE input, and features integrated 33-Ω series resistors on B-port outputs to suppress overshoot/undershoot in high-speed digital interfaces.
For engineers reviewing the SN74BCT2245DW datasheet, SN74BCT2245DW pinout, SN74BCT2245DW application, or SN74BCT2245DW equivalent, key selection considerations include its BiCMOS architecture for low ICCZ, 12-mA B-port sink/source capability, 3.3 ns typical propagation delay (A→B), thermal resistance of 58°C/W in SOIC-DW package, and JESD22-compliant ESD protection up to 2000-V HBM.
Technical Context
This device implements dual-bus transceivers using BiCMOS logic, enabling data flow either from A-to-B or B-to-A based on the DIR signal level while isolating both buses when OE is high. Its internal structure includes separate A-port and B-port output stages, with B-port outputs incorporating monolithic 33-Ω series termination resistors.
The SN74BCT2245DW uses positive-logic control: low OE enables outputs, and DIR determines direction-low DIR routes B data to A bus, high DIR routes A data to B bus. Power-up isolation is ensured by tying OE to VCC via a pullup resistor, and all unused inputs must be held at VCC or GND per TI SCBA004 guidance.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - ensures compatibility with standard 5-V TTL/CMOS systems and stable operation across industrial voltage tolerances. |
| B-Port Output Drive | ±12 mA - supports direct interface to MOS gates and transmission lines without external current-limiting resistors. |
| A-Port Low-Level Output Current | 24 mA - provides robust sink capability for TTL-compatible loads and fanout requirements. |
| Propagation Delay (A→B) | 1.0 ns to 4.9 ns (typ. 3.3 ns at VCC = 5 V) - enables reliable timing in high-speed bus bridging up to ~100 MHz clock domains. |
| ESD Protection | 2000-V HBM, 200-V MM, 1000-V CDM - exceeds JEDEC standards for handling in automated assembly and field-replaceable modules. |
| Thermal Resistance θJA | 58°C/W - defines maximum power dissipation limit (≈172 mW at ΔT = 10°C rise) for SOIC-DW package in still-air conditions. |
| ICCZ Quiescent Current | 8–14 mA - significantly reduced vs. older bipolar-only transceivers, lowering standby power in multi-device bus systems. |
Pinout & Package
SN74BCT2245DW is housed in a 20-pin SOIC (DW) package measuring 12.83 mm × 7.5 mm × 2.65 mm max height, with 1.27-mm lead pitch and RoHS-compliant NiPdAu lead finish. The package is moisture-sensitivity Level-1 rated for unlimited reflow at 260°C.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | DIR | Direction control input: low enables B→A data transfer; high enables A→B transfer. |
| 2–9 | A1–A8 | A-side data inputs/outputs - bidirectional I/O pins connected to source bus (e.g., microcontroller data bus). |
| 10 | GND | Ground reference for all internal circuitry and I/O stages. |
| 11 | VCC | Positive supply rail (4.5–5.5 V) powering BiCMOS logic and output drivers. |
| 12 | OE | Output-enable control: low enables transceiver operation; high forces all outputs into high-impedance state. |
| 13–20 | B1–B8 | B-side data inputs/outputs - bidirectional I/O pins with integrated 33-Ω series resistors, optimized for line driving and MOS gate interfacing. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 33-Ω B-port series resistors | Eliminates need for external termination components, reducing PCB area and signal integrity risk in high-speed bus stubs. |
| BiCMOS process technology | Combines bipolar speed and CMOS low static power, achieving <15 mA ICCZ while maintaining sub-5 ns propagation delays. |
| 3-state bus isolation | OE-controlled high-impedance mode prevents bus contention during power sequencing or system reset events. |
| JESD22-compliant ESD protection | 2000-V HBM rating allows safe handling in non-ESD-controlled environments during board assembly and field service. |
| Wide operating temperature range | 0°C to 70°C ambient rating supports commercial and industrial embedded applications without derating. |
Applications
| Microcontroller Bus Expansion | Legacy System Interfacing |
|---|---|
|
Use Scenario: Expanding GPIO or data bus width of an 8-bit MCU to drive additional peripherals or memory banks. IC Role / Device Role / Timing Role: Bidirectional data bridge between MCU's primary data bus (A port) and extended peripheral bus (B port), controlled by MCU GPIOs for DIR and OE. Use Value: Enables seamless 8-bit data transfer without external pullups or series resistors on B-side lines, reducing component count and layout complexity. |
Use Scenario: Connecting modern 5-V logic systems to legacy TTL-based instrumentation or industrial controllers. IC Role / Device Role / Timing Role: Level-shifting and bus-isolation transceiver between newer microprocessor subsystems (A port) and older TTL bus segments (B port). Use Value: Matches TTL voltage thresholds (VIL ≤ 0.8 V, VIH ≥ 2.0 V) and drives 12-mA loads directly, ensuring interoperability without discrete level shifters. |
| Memory Subsystem Interface | Programmable Logic Interconnect |
|
Use Scenario: Isolating and routing address/data between FPGA-configured memory controller and parallel SRAM/Flash devices. IC Role / Device Role / Timing Role: Direction-controlled transceiver managing multiplexed address/data bus (A port) and dedicated memory bus (B port), synchronized to FPGA control signals. Use Value: 3.3 ns typical A→B delay supports memory access cycles ≤30 ns, and 33-Ω B-port termination minimizes reflections on 2- to 4-inch trace runs. |
Use Scenario: Enabling dynamic reconfiguration of interconnect paths between CPLD/FPGA I/O banks and external logic arrays. IC Role / Device Role / Timing Role: Reconfigurable bus switch that routes signals between two logic domains under control of configuration state machine (DIR/OE). Use Value: High-impedance isolation during configuration transitions prevents metastability or short-circuits; BiCMOS design ensures deterministic setup/hold timing margins. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LS245N | Bipolar TTL process; no integrated series resistors; higher ICCZ (60–80 mA); slower propagation (10–25 ns); 7-V absolute max VCC. | Lacks B-port termination; requires external resistors for clean edge control; unsuitable for >20-MHz bus rates without added compensation. | Select only for legacy TTL-only systems where BiCMOS power savings and speed are not required. |
| SN74LVC245APWR | Low-voltage CMOS (1.65–3.6 V); 32-mA drive; no built-in termination; 3.3-V compatible; smaller TSSOP-20 package. | Not pin-compatible; incompatible supply range; lacks 33-Ω resistors; requires external termination for 5-V bus interfacing. | Choose for 3.3-V systems needing lower power and higher drive, but not as drop-in replacement for SN74BCT2245DW in 5-V designs. |
Compared with SN74LS245N, SN74BCT2245DW delivers 3× faster propagation and 80% lower quiescent current; versus SN74LVC245APWR, it offers native 5-V operation and integrated B-port termination-critical for noise-sensitive industrial backplanes.
Availability
SN74BCT2245DW is available at Aetrix Electronics and suitable for microcontroller bus expansion, legacy system interfacing, memory subsystem interface, programmable logic interconnect, and industrial backplane bridging requiring stable component supply and long-term obsolescence management.
Supply support for SN74BCT2245DW 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 for industrial, automotive, and communications markets.
The SN74BCT2245DW belongs to TI's BCT (Bipolar-CMOS Transceiver) logic family, engineered specifically for high-speed, low-power bidirectional bus interfacing in 5-V systems where signal integrity and bus contention avoidance are critical.
FAQ
What is the recommended power-up sequence for SN74BCT2245DW to avoid bus contention?
TI recommends tying OE to VCC through a pullup resistor (value determined by driver sink capability) to ensure outputs remain in high-impedance state during power ramp-up. DIR may float initially but must be stabilized before OE is asserted low. This sequence prevents unintended data leakage or bus conflicts during system initialization. The SN74BCT2245DW datasheet specifies this requirement in Section 1 to guarantee safe power sequencing behavior.
Does SN74BCT2245DW support hot-swap or live-insertion into a powered bus?
No, SN74BCT2245DW does not support hot-swap operation. Its absolute maximum ratings specify VO ≤ 5.5 V when outputs are disabled, and applying voltage to B-port pins while VCC is unpowered risks latch-up or damage due to internal parasitic paths. For live-insertion, use purpose-built hot-swap controllers or buffers with power-on reset and undervoltage lockout. The SN74BCT2245DW is intended for fixed-installation, power-cycled systems only.
Can SN74BCT2245DW drive 50-Ω transmission lines directly?
No, SN74BCT2245DW's B-port 33-Ω series resistors are optimized for stub-loaded 5-V TTL buses-not matched 50-Ω point-to-point lines. Driving 50-Ω lines would cause excessive attenuation and reflection due to impedance mismatch. For true 50-Ω line driving, use dedicated line drivers like SN65LVDS31 or SN75ALS197. The SN74BCT2245DW is best applied in multidrop bus topologies with unterminated stubs ≤3 inches.
What is the maximum continuous current rating per B-port output of SN74BCT2245DW?
Each B-port output is rated for ±12 mA DC output current under recommended operating conditions (VCC = 4.5–5.5 V, TA = 0–70°C). Exceeding this value risks parametric shift or accelerated wear. The datasheet specifies IOH = −12 mA and IOL = 12 mA as absolute limits for sustained operation. Derating is required above 50°C ambient. Always verify load conditions against the SN74BCT2245DW electrical characteristics table (page 4) before final design sign-off.
Is SN74BCT2245DW pin-compatible with other 20-pin octal transceivers like SN74ALS245 or SN74F245?
No, SN74BCT2245DW is not pin-compatible with SN74ALS245 or SN74F245. While all are 20-pin octal transceivers, their pinouts differ: SN74ALS245 places DIR at Pin 19 and OE at Pin 1, whereas SN74BCT2245DW assigns DIR to Pin 1 and OE to Pin 12. Swapping them without PCB redesign will result in functional failure. Always validate pin mapping using the "DB, DW, N, OR NS PACKAGE (TOP VIEW)" diagram on page 1 of the SN74BCT2245DW datasheet.
SN74BCT2245DW 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:
- Transceiver, Non-Inverting
- Number of Elements:
- 1
- Number of Bits per Element:
- 8
- Input Type:
- -
- Output Type:
- 3-State
- Current - Output High, Low:
- 3mA, 24mA; 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
SN74BCT2245DW FAQ
1.How can I place an order for SN74BCT2245DW through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74BCT2245DW 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 SN74BCT2245DW reliable?
The price and inventory of SN74BCT2245DW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74BCT2245DW is usually 5 days.
3.What payment methods are accepted for SN74BCT2245DW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74BCT2245DW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74BCT2245DW?
SN74BCT2245DW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74BCT2245DW 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 SN74BCT2245DW?
For technical support, including SN74BCT2245DW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74BCT2245DW requirements.
6.How does Aetrix verify that SN74BCT2245DW is sourced from the original manufacturer or authorized distributors?
All SN74BCT2245DW 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 SN74BCT2245DW meets industry standards.
7.What is the process for return or replacement of SN74BCT2245DW?
All SN74BCT2245DW units undergo pre-shipment inspection (PSI). If there is an issue with SN74BCT2245DW, 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 SN74BCT2245DW part is unused and in its original packaging.
Return procedure for SN74BCT2245DW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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