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Texas Instruments SN74F245DWR
- Part No.:
- SN74F245DWR
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74F245DWR.pdf
- Description:
- IC TXRX NON-INVERT 5.5V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,201
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Product details
Overview
SN74F245DWR from Texas Instruments is an octal bus transceiver with 3-state outputs, designed for asynchronous bidirectional data transfer between A and B buses in TTL-level systems. It features direction control (DIR), output enable (OE), 20-pin SOIC (DW) package, operating temperature range 0°C to 70°C, and supports up to 128 mA sink current on B-side outputs.
For engineers reviewing the SN74F245DWR datasheet, SN74F245DWR pinout, SN74F245DWR application, or SN74F245DWR equivalent, this page delivers verified electrical specs, functional truth table, real-world isolation behavior, and direct alternatives for legacy TTL bus interface design.
Technical Context
The SN74F245DWR implements dual-bus bidirectional data routing via a single DIR input that selects A→B or B→A flow, while OE independently places all outputs in high-impedance state for bus isolation. Its TTL-compatible inputs accept VIH ≥ 2 V and VIL ≤ 0.8 V, and outputs drive standard TTL loads with VOH ≥ 2.4 V (at IOH = –3 mA on A-side) and VOL ≤ 0.5 V (at IOL = 24 mA on A-side).
Switching performance is characterized at VCC = 5 V, CL = 50 pF: propagation delays tPLH/tPHL range 1.7–7 ns depending on direction and temperature, while enable/disable times tPZH/tPLZ reach 2.7 ns (min) to 9 ns (max), ensuring predictable timing in synchronous bus arbitration and shared-memory interconnects.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - compatible with standard 5 V TTL power rails; operation outside this range risks damage or undefined logic states. |
| Operating Temperature | 0°C to 70°C - commercial-grade rating suitable for industrial control panels and non-military embedded systems. |
| Output Drive (B-side) | 128 mA sink (IOL), 15 mA source (IOH) - sufficient to drive multiple TTL inputs or short traces without external buffering. |
| Propagation Delay | 1.7–7 ns - enables reliable operation in 20+ MHz bus clock domains when load capacitance is ≤50 pF. |
| 3-State Enable Time | tPZH = 2.2–8 ns - fast bus release critical for multi-master arbitration and dynamic bus sharing. |
| Input Thresholds | VIH ≥ 2 V, VIL ≤ 0.8 V - ensures robust noise margin against TTL-compatible signal sources and avoids metastability. |
| Package | SOIC-20 (DW) - surface-mount, 7.5 mm × 13.3 mm footprint, RoHS-compliant NIPDAU finish, MSL Level-1. |
Pinout & Package
SN74F245DWR uses a 20-pin Small Outline Integrated Circuit (SOIC) package (DW), 7.5 mm wide body, 13.3 mm length, 2.65 mm max height, with 1.27 mm lead pitch and gull-wing leads. Pin 1 is located at top-left corner with index marking.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (DIR) | Direction Control Input | Low = B→A data flow; High = A→B data flow; TTL-compatible, drives internal bus switch matrix. |
| 2–9 (A1–A8) | Port A Data I/O | Bidirectional TTL I/O pins connected to A bus; high-impedance when OE = High or device powered down. |
| 10 (GND) | Ground Reference | Primary return path for all internal logic and output currents; must be low-inductance connection to system ground plane. |
| 11 (VCC) | Power Supply | +5 V supply input; requires local 0.1 µF ceramic decoupling capacitor placed within 5 mm of pin. |
| 12–19 (B1–B8) | Port B Data I/O | Bidirectional TTL I/O pins connected to B bus; higher drive strength than A-side (128 mA vs. 48 mA sink). |
| 20 (OE) | Output Enable Input | Active-Low control: Low = outputs enabled; High = all A/B pins enter 3-state (high-Z) for bus isolation. |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional Bus Control | Single DIR pin configures data flow direction without external logic, reducing PCB routing complexity in dual-bus systems. |
| Independent Output Disable | OE pin isolates both A and B ports simultaneously, enabling clean hot-swap and multi-drop bus arbitration. |
| Asymmetric Output Strength | B-side outputs deliver 128 mA sink capability-ideal for driving heavier loads like address latches or memory buffers-while A-side provides 48 mA for lighter control signals. |
| TTL-Compatible Interface | Meets standard TTL voltage thresholds and loading requirements, ensuring plug-in compatibility with legacy 74-series logic and microprocessor buses. |
| SOIC Packaging | DW package offers compact surface-mount footprint with industry-standard solder profile (MSL Level-1, 260°C peak reflow), supporting automated assembly. |
Applications
| Industrial PLC Backplane | Legacy Microprocessor Bus Extension |
|---|---|
Use Scenario: Interfacing a 16-bit CPU bus to isolated I/O expansion modules across a DIN-rail mounted backplane. IC Role / Device Role / Timing Role: SN74F245DWR acts as a bidirectional data buffer between CPU data bus and peripheral module data bus, controlled by CPU-generated DIR and OE signals during read/write cycles. Use Value: Enables deterministic bus turnaround with sub-7 ns propagation delay and full 3-state isolation during bus grant handoff, preventing contention in multi-slot architectures. | Use Scenario: Extending Z80 or 8085 address/data multiplexed bus to off-board memory or peripheral cards using separate A and B bus segments. IC Role / Device Role / Timing Role: SN74F245DWR serves as a bus transceiver to demultiplex AD0–AD7 into dedicated A0–A7 (address) and D0–D7 (data) paths under control of ALE and RD/WR strobes. Use Value: Provides TTL-level drive strength and precise timing alignment (tPLH/tPHL ≤ 7 ns) required for reliable 4–6 MHz Z80 bus timing margins. |
| Test Equipment Signal Routing | Automated Test Fixture Interface |
Use Scenario: Reconfigurable signal path switching inside benchtop logic analyzers or protocol testers where DUT signals must be routed to multiple measurement channels. IC Role / Device Role / Timing Role: SN74F245DWR functions as a programmable bidirectional signal coupler, with DIR selecting stimulus or response direction and OE enabling channel isolation during calibration. Use Value: Delivers repeatable 3-state leakage < 10 µA and fast enable/disable (tPZH/tPLZ ≤ 9 ns), critical for low-noise, high-fidelity signal path switching. | Use Scenario: Interfacing FPGA-based test controllers to legacy TTL-based DUT boards in production ATE fixtures requiring hot-plug-safe bus access. IC Role / Device Role / Timing Role: SN74F245DWR provides galvanically isolated bus coupling between tester controller and DUT, with OE synchronized to fixture safety interlocks. Use Value: Ensures zero bus contention during fixture initialization or fault recovery via hardware-controlled OE assertion, eliminating risk of latch-up or signal corruption. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LS245N | Lower drive (24 mA sink), slower speed (tPLH up to 15 ns), PDIP-20 only, no RoHS option | Acceptable for low-speed (< 5 MHz), low-current bus extensions where thermal budget is constrained | Choose if legacy through-hole assembly is required and speed/power trade-off is acceptable |
| SN74AHCT245PW | CMOS input (5 V tolerant), faster (tPLH = 3.5 ns typ), TSSOP-20, RoHS, wider VCC range (4.5–5.5 V) | Better noise immunity and lower static current, but requires careful handling of unused inputs to avoid floating states | Prefer for new designs needing improved speed, lower ICC, and modern packaging-verify DIR/OE logic levels match system drivers |
Compared with SN74LS245N, SN74F245DWR delivers 2× higher B-side drive and ~50% faster propagation; versus SN74AHCT245PW, it offers proven TTL noise margin and simpler input biasing but consumes more quiescent current and lacks 5 V-tolerant inputs.
Availability
SN74F245DWR is available at Aetrix Electronics and suitable for industrial control backplanes, legacy microprocessor bus extensions, test equipment signal routing, and automated test fixture interfaces requiring stable component supply over extended production lifecycles.
Supply support for SN74F245DWR 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 90 years of innovation in industrial, automotive, and communications markets.
The SN74F245DWR belongs to TI's 74F family of fast TTL logic devices, engineered specifically for high-speed, low-latency bus interfacing in legacy and retrofit systems where compatibility with existing 5 V TTL infrastructure is mandatory.
FAQ
What is the maximum continuous output current rating for SN74F245DWR on the B-side pins?
The SN74F245DWR supports up to 128 mA sink current (IOL) on B1–B8 pins at VCC = 4.5 V and TA = 25°C, per the absolute maximum ratings table. This rating applies under steady-state DC conditions; transient overload beyond 1 second is not recommended. Always verify PCB trace width and thermal relief to sustain this current without exceeding junction temperature limits.
Can SN74F245DWR operate with a 3.3 V supply?
No, SN74F245DWR is not rated for 3.3 V operation. Its recommended VCC range is strictly 4.5 V to 5.5 V, and absolute maximum VCC is 7 V. Applying 3.3 V will result in undefined logic thresholds, excessive propagation delay, and potential failure to meet VOH/VOL specifications. For 3.3 V systems, consider SN74LVC245A or similar CMOS alternatives.
Is SN74F245DWR pin-compatible with SN74LS245?
Yes, SN74F245DWR and SN74LS245 share identical 20-pin SOIC (DW) and PDIP (N) footprints and pin functions-including DIR, OE, A1–A8, B1–B8, VCC, and GND-but differ electrically: SN74F245DWR has faster timing, higher drive strength, and different input/output voltage thresholds. Mechanical replacement is possible; functional validation in-circuit is required.
What does the 'DWR' suffix indicate in SN74F245DWR?
The 'DWR' suffix identifies the specific packaging and packaging format: 'DW' denotes the SOIC-20 package type per TI's package drawing DW0020A, and 'R' indicates tape-and-reel packaging (2000 units per reel). The full orderable part number SN74F245DWR is RoHS-compliant, active, and qualified for commercial temperature range (0°C to 70°C).
How does the direction control (DIR) pin interact with output enable (OE) in SN74F245DWR?
In SN74F245DWR, DIR controls data flow direction only when OE is asserted (low); when OE is deasserted (high), all A and B pins enter high-impedance state regardless of DIR state. This allows independent bus isolation (via OE) and directional routing (via DIR), enabling safe multi-master arbitration and dynamic bus topology reconfiguration.
SN74F245DWR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74F
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- 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; 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
SN74F245DWR FAQ
1.How can I place an order for SN74F245DWR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74F245DWR 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 SN74F245DWR reliable?
The price and inventory of SN74F245DWR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74F245DWR is usually 5 days.
3.What payment methods are accepted for SN74F245DWR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74F245DWR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74F245DWR?
SN74F245DWR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74F245DWR 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 SN74F245DWR?
For technical support, including SN74F245DWR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74F245DWR requirements.
6.How does Aetrix verify that SN74F245DWR is sourced from the original manufacturer or authorized distributors?
All SN74F245DWR 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 SN74F245DWR meets industry standards.
7.What is the process for return or replacement of SN74F245DWR?
All SN74F245DWR units undergo pre-shipment inspection (PSI). If there is an issue with SN74F245DWR, 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 SN74F245DWR part is unused and in its original packaging.
Return procedure for SN74F245DWR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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