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Texas Instruments SN74F2245DBR
- Part No.:
- SN74F2245DBR
- Manufacturer:
- Texas Instruments
- Package:
- -
- Datasheet:
-
SN74F2245DBR.pdf
- Description:
- BUS TRANSCEIVER
- Quantity:
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Inventory:24,000
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Product details
Overview
SN74F2245DBR from Texas Instruments is an octal bus transceiver with 3-state outputs, designed for bidirectional asynchronous data transfer between two 8-bit buses (A↔B) in TTL-level systems. It features direction control (DIR), output enable (OE), 12 mA sink capability per output, integrated 25-Ω series resistors to suppress signal overshoot/undershoot, and operates over 0°C to 70°C.
For engineers reviewing the SN74F2245DBR datasheet, SN74F2245DBR pinout, SN74F2245DBR application, or SN74F2245DBR equivalent, key selection considerations include bidirectional bus isolation timing (tPLH/tPHL ≤ 6.6 ns), 3-state control latency (tPZH/tPLZ ≤ 12 ns), 5 V supply compatibility, and SSOP-20 package constraints for high-density PCB layouts.
Technical Context
The SN74F2245DBR implements dual 8-bit bidirectional data paths controlled by a single DIR input: low DIR enables B→A transmission, high DIR enables A→B transmission. OE independently disables all outputs into high-impedance state, providing bus isolation without requiring external logic.
Each I/O port supports ±12 mA drive strength under 5 V operation, with internal 25-Ω series termination on lower output circuitry to dampen ringing on stub-loaded or unterminated transmission lines-critical for reliable memory address register buffering and backplane interconnects.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage (VCC) | 4.5 V to 5.5 V - Ensures compatibility with standard TTL and 5 V CMOS logic rails. |
| Propagation Delay (tPLH/tPHL) | ≤ 6.6 ns at VCC = 4.5–5.5 V, CL = 50 pF - Enables sub-150 MHz bus handshaking in synchronous designs. |
| Output Drive (IOL) | 12 mA sink per A/B pin - Sufficient to drive multiple TTL loads or terminated transmission lines. |
| 3-State Enable/Disable Time | tPZH ≤ 7.5 ns, tPLZ ≤ 6.8 ns - Minimizes bus contention windows during direction switching. |
| Operating Temperature | 0°C to 70°C - Qualified for commercial-grade embedded and computing applications. |
| Input Thresholds (VIH/VIL) | VIH ≥ 2.0 V, VIL ≤ 0.8 V - Guarantees noise margin > 0.4 V with standard TTL inputs. |
| Output Termination | Integrated 25-Ω series resistor on each output - Reduces edge-induced overshoot/undershoot without external components. |
Pinout & Package
SN74F2245DBR uses a 20-pin Plastic Small-Outline Package (SSOP-DB), 5.3 mm wide, 7.2 mm long, 2.0 mm height, 0.65 mm lead pitch. Pin 1 is marked by a beveled corner or dot; leads are gull-wing, surface-mount compatible.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | DIR | Direction control: LOW = B→A data flow; HIGH = A→B data flow. |
| 2–9 | A1–A8 | 8-bit bidirectional data port A - connects to source bus (e.g., CPU data bus). |
| 10 | GND | Ground reference for logic and power return path. |
| 11–18 | B1–B8 | 8-bit bidirectional data port B - connects to destination bus (e.g., memory address register). |
| 19 | OE | Output enable: LOW = active data transfer; HIGH = all A/B outputs in high-Z isolation. |
| 20 | VCC | +5 V power supply - must be decoupled locally with 0.1 µF ceramic capacitor. |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional Bus Transceiver | Single DIR pin controls full 8-bit A↔B data flow direction - eliminates need for separate transmit/receive buffers. |
| 3-State Output Control | Independent OE input places all A/B pins in high-impedance state - enables shared bus arbitration without external switches. |
| Integrated Output Damping | 25-Ω series resistor per output reduces signal integrity issues on unterminated traces - lowers layout risk in compact PCBs. |
| TTL-Compatible Interface | VIH/VIL thresholds and 12 mA drive match legacy TTL loading - ensures drop-in replacement in 74F/74AS systems. |
| Commercial Temperature Range | 0°C to 70°C operation - validated for desktop computing, industrial controllers, and instrumentation where extended temp not required. |
Applications
| Memory Address Buffering | CPU-to-Peripheral Data Bridge |
|---|---|
|
Use Scenario: Isolating and driving CPU address lines to multiple memory ICs with varying load capacitance. IC Role / Device Role / Timing Role: Bidirectional address latch buffer that prevents bus contention during read/write cycles via DIR and OE coordination. Use Value: Integrated 25-Ω termination suppresses ringing on long address traces, improving setup/hold margin at 20+ MHz clock rates. |
Use Scenario: Interfacing an 8-bit microcontroller data bus to external peripherals (ADC, DAC, UART) sharing a common bus segment. IC Role / Device Role / Timing Role: Direction-controlled transceiver enabling CPU-initiated writes and peripheral-initiated reads using shared data lines. Use Value: Sub-7 ns propagation delay and <7 ns 3-state disable time minimize bus turnaround overhead, increasing effective throughput. |
| Backplane Signal Translation | Legacy System Bus Expansion |
|
Use Scenario: Extending a TTL-level system bus across a multi-board chassis with stubbed connectors and variable trace lengths. IC Role / Device Role / Timing Role: Point-to-point bus repeater with impedance-matched outputs to maintain signal integrity across distributed loads. Use Value: 12 mA sink strength drives up to 10 TTL loads while 25-Ω series resistance damps reflections from impedance discontinuities. |
Use Scenario: Adding new I/O modules to an aging industrial controller using original 74F-series bus architecture. IC Role / Device Role / Timing Role: Pin-compatible upgrade for obsolete 74F245 variants, retaining existing PCB layout and firmware logic. Use Value: Identical function, timing, and electrical specs to SN74F245 but with enhanced output damping - no redesign needed. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bidirectional bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74F245N | No integrated 25-Ω output resistors; higher overshoot risk on fast edges; PDIP-20 only. | Suitable for low-speed (<10 MHz), short-trace applications where external termination is acceptable. | Prefer SN74F2245DBR when board space is constrained or signal integrity on longer traces is critical. |
| SN74LS245N | Lower drive (8 mA), slower propagation (≤15 ns), wider VCC tolerance (4.75–5.25 V), LS-family power consumption. | Better suited for low-power, noise-immune systems where speed is secondary to current efficiency. | Choose SN74F2245DBR for performance-critical 5 V TTL systems needing faster timing and built-in damping. |
Compared with SN74F245N and SN74LS245N, the SN74F2245DBR delivers superior signal integrity via on-die 25-Ω termination, tighter timing (≤6.6 ns vs. ≥12 ns), and SSOP packaging for modern high-density layouts-making it optimal for upgrading legacy bus interfaces without sacrificing reliability.
Availability
SN74F2245DBR is available at Aetrix Electronics and suitable for memory subsystem design, industrial controller bus expansion, and legacy system upgrades requiring stable component supply and verified 74F-family compatibility.
Supply support for SN74F2245DBR 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, logic, and interface solutions for industrial, automotive, and communications markets.
The SN74F2245DBR belongs to TI's 74F Fast TTL logic family, engineered for high-speed digital system interconnects where timing precision, bus isolation, and robust signal integrity are essential.
FAQ
What is the primary function of the SN74F2245DBR?
The SN74F2245DBR is an octal bidirectional bus transceiver that routes data between two 8-bit buses (A and B) under control of DIR and OE inputs. It provides 3-state outputs, 12 mA sink capability, and integrated 25-Ω series resistors to suppress signal ringing-making it ideal for memory address buffering and CPU-peripheral interfacing in 5 V TTL systems.
Does the SN74F2245DBR support 3.3 V operation?
No, the SN74F2245DBR is specified only for 4.5 V to 5.5 V supply operation and is not rated for 3.3 V logic levels. Its input thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V) and output drive characteristics are optimized for 5 V TTL compatibility. Using it at 3.3 V may result in unreliable switching or excessive current draw.
What does the "DB" in SN74F2245DBR indicate?
The "DB" suffix denotes the Plastic Small-Outline Package (SSOP) variant with 20 pins and 0.65 mm lead pitch. This surface-mount package measures 7.2 mm × 5.3 mm × 2.0 mm and is distinct from the "N" (PDIP-20) and "DW" (SOIC-20) variants-ensuring correct footprint selection during PCB layout for the SN74F2245DBR.
How does the SN74F2245DBR differ from the SN74F245?
The SN74F2245DBR integrates 25-Ω series resistors in its lower output circuit to reduce overshoot and undershoot, whereas the SN74F245 lacks this feature. Both share identical pinout, timing, and logic function-but the SN74F2245DBR improves signal integrity on marginal traces without adding external components.
Is the SN74F2245DBR still in production?
No-the SN74F2245DBR is marked as OBSOLETE by Texas Instruments per official packaging documentation. However, Aetrix Electronics maintains legacy inventory and offers traceable, tested units for ongoing production support, repair, and obsolescence mitigation programs targeting industrial and embedded systems.
SN74F2245DBR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- *
- Package/Case:
- -
- Packaging:
- Bulk
- Product Status:
- Active
- Logic Type:
- -
- Number of Elements:
- -
- Number of Bits per Element:
- -
- Input Type:
- -
- Output Type:
- -
- Current - Output High, Low:
- -
- Voltage - Supply:
- -
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- -
- Supplier Device Package:
- -
SN74F2245DBR FAQ
1.How can I place an order for SN74F2245DBR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74F2245DBR 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 SN74F2245DBR reliable?
The price and inventory of SN74F2245DBR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74F2245DBR is usually 5 days.
3.What payment methods are accepted for SN74F2245DBR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74F2245DBR transactions.
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4.How is shipping managed for SN74F2245DBR?
SN74F2245DBR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74F2245DBR 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 SN74F2245DBR?
For technical support, including SN74F2245DBR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74F2245DBR requirements.
6.How does Aetrix verify that SN74F2245DBR is sourced from the original manufacturer or authorized distributors?
All SN74F2245DBR 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 SN74F2245DBR meets industry standards.
7.What is the process for return or replacement of SN74F2245DBR?
All SN74F2245DBR units undergo pre-shipment inspection (PSI). If there is an issue with SN74F2245DBR, 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 SN74F2245DBR part is unused and in its original packaging.
Return procedure for SN74F2245DBR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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