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Texas Instruments SN74ALS245ADWR
- Part No.:
- SN74ALS245ADWR
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74ALS245ADWR.pdf
- Description:
- IC TXRX NON-INVERT 5.5V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,224
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Product details
Overview
SN74ALS245ADWR from Texas Instruments is an octal bus transceiver with 3-state outputs, designed for asynchronous bidirectional data transfer between A and B buses in 5-V TTL systems. It operates from 4.5 V to 5.5 V, delivers max propagation delay of 10 ns at 5 V, supports ±24 mA output drive, and features pnp input structure to reduce DC loading. It is used in legacy industrial backplane interfaces and memory-mapped I/O expansion.
For engineers reviewing the SN74ALS245ADWR datasheet, SN74ALS245ADWR pinout, SN74ALS245ADWR application, or SN74ALS245ADWR equivalent, key selection criteria include 3-state bus isolation timing, direction-control logic behavior, VCC=5 V compatibility, and SOIC-20 package thermal performance (θJA = 58°C/W).
Technical Context
The SN74ALS245ADWR implements dual-function control logic: DIR selects data flow direction (A→B when high, B→A when low), while OE enables/disables all outputs into high-impedance state. Its ALS (Advanced Low-Power Schottky) architecture provides TTL-compatible voltage thresholds (VIH = 2 V, VIL = 0.8 V) and reduced power consumption versus standard LS.
Propagation delays are asymmetrically specified: tPLH/tPHL ≤ 10 ns (A↔B), tPZH/tPZL ≤ 20 ns (OE→output enable/disable), and tPHZ/tPLZ ≤ 10 ns (OE→output disable/enable). Output drive capability is rated at IOL = 24 mA (min) and IOH = –15 mA (min) under recommended conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.5 V to 5.5 V - Ensures robust operation across industrial 5-V rail tolerances. |
| Max Propagation Delay | 10 ns at VCC = 5 V - Enables reliable timing in 100-MHz bus cycles with margin. |
| Output Drive (IOL) | 24 mA min - Sustains signal integrity driving 50-pF loads across 20-cm PCB traces. |
| 3-State Enable Time | tPHZ ≤ 10 ns - Allows rapid bus arbitration without contention windows. |
| Input Structure | pnp inputs - Reduces DC loading on upstream drivers, lowering system power. |
| Thermal Impedance | θJA = 58°C/W (SOIC-DW) - Supports continuous operation at TA = 70°C with <150 mW dissipation. |
Pinout & Package
SN74ALS245ADWR uses a 20-pin SOIC (DW) package, 7.5 mm × 12.8 mm body, 1.27 mm lead pitch, 2.65 mm max height, RoHS-compliant NiPdAu lead finish, and MSL Level-1 rating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4, 5, 6, 7, 8 | A1–A8 inputs/outputs | One side of bidirectional data bus; connected to source system (e.g., CPU address/data lines). |
| 11, 12, 13, 14, 15, 16, 17, 18 | B1–B8 inputs/outputs | Other side of bidirectional data bus; connected to peripheral or memory subsystem. |
| 9 | GND | Power return reference for all logic and I/O circuits. |
| 10 | VCC | +5 V supply input; decoupling capacitor required within 10 mm. |
| 19 | DIR | Direction control: high = A→B, low = B→A; TTL-compatible input threshold. |
| 20 | OE | Output enable: low = active (bus enabled), high = disabled (3-state isolation). |
Key Features
| Feature | Design Value |
|---|---|
| Asynchronous bidirectional data path | Eliminates need for separate transmit/receive buffers in shared-bus architectures. |
| 3-state outputs with fast enable/disable | tPHZ ≤ 10 ns and tPLZ ≤ 15 ns prevent bus contention during mode switching. |
| pnp input structure | Reduces input current to ≤0.1 mA, easing drive requirements for legacy TTL sources. |
| TTL-compatible voltage thresholds | VIH = 2 V / VIL = 0.8 V ensures interoperability with 74LS, 74F, and microcontroller GPIOs. |
| SOIC-20 RoHS-compliant packaging | Enables automated assembly and meets IPC/JEDEC MS-013 footprint standards. |
Applications
| Industrial Backplane Interface | Legacy Memory Expansion |
|---|---|
Use Scenario: Isolating CPU local bus from extended I/O backplane in programmable logic controllers. IC Role / Device Role / Timing Role: Bidirectional level-shifting transceiver managing address/data multiplexing between MPU and peripheral slots. Use Value: 10 ns propagation delay and 24 mA drive maintain signal fidelity across 15 cm backplane traces at 8 MHz. | Use Scenario: Expanding 8-bit microcontroller address/data bus to support external EPROM and RAM modules. IC Role / Device Role / Timing Role: Bus isolator enabling time-multiplexed access to multiple memory banks via DIR/OE control. Use Value: pnp inputs reduce loading on weak MCU drivers; 3-state isolation prevents memory contention during refresh cycles. |
| Test Equipment Data Acquisition | Automated Test Fixture Control |
Use Scenario: Routing sensor data between ADC front-end and host controller in benchtop DMMs. IC Role / Device Role / Timing Role: Direction-controlled data conduit synchronizing sample capture and upload phases. Use Value: tPZH ≤ 20 ns enables deterministic bus release before next conversion trigger, eliminating sampling skew. | Use Scenario: Interfacing FPGA-based test sequencer with DUT's parallel control bus in ATE systems. IC Role / Device Role / Timing Role: Bus transceiver providing isolated, direction-switchable communication between tester and device-under-test. Use Value: OE-controlled 3-state operation allows safe hot-plug insertion of DUT boards without bus conflicts. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74AS245DWR | Faster tPLH/tPHL (7.5 ns max), higher IOL (64 mA), but increased ICC (95 mA vs. 60 mA). | Better suited for high-speed bus arbitration; less suitable for low-power or thermally constrained designs. | Select when propagation delay <8 ns is mandatory and power budget allows +50% ICC increase. |
| SN74ALS245ANSR | Same ALS family specs, but SOP-20 (NS) package: θJA = 60°C/W, 24.4 mm tape width, 13.0 mm B0 cavity. | Preferred for space-constrained PCBs using SOP footprints; requires different land pattern and stencil design. | Select when board layout mandates SOP-20 instead of SOIC-20, with no change to logic or timing behavior. |
Compared with SN74AS245DWR and SN74ALS245ANSR, the SN74ALS245ADWR offers optimal balance of speed (10 ns), power (60 mA ICC), and thermal performance (58°C/W) in the industry-standard SOIC-20 package-making it ideal for cost-sensitive, thermally stable 5-V industrial control designs.
Availability
SN74ALS245ADWR is available at Aetrix Electronics and suitable for industrial backplane interfaces, legacy memory expansion, test equipment data acquisition, and automated test fixture control requiring stable component supply over extended production lifecycles.
Supply support for SN74ALS245ADWR 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 company headquartered in Dallas, Texas, delivering analog and embedded processing solutions for industrial, automotive, and personal electronics markets.
The SN74ALS245ADWR belongs to TI's legacy TTL logic product line, engineered specifically for robust, pin-compatible replacement of 74LS245 in 5-V systems where ALS speed-power tradeoffs optimize reliability and noise immunity.
FAQ
What is the maximum operating temperature range for the SN74ALS245ADWR?
The SN74ALS245ADWR is rated for commercial temperature operation from 0°C to 70°C. This range is validated per TI's recommended operating conditions and aligns with its SOIC-DW package thermal characteristics (θJA = 58°C/W). Operation outside this range may compromise timing margins or output drive stability.
Does the SN74ALS245ADWR support true bidirectional data flow without external logic?
Yes, the SN74ALS245ADWR supports true bidirectional data flow using only its DIR input: when DIR = high, data passes from A ports to B ports; when DIR = low, data flows from B ports to A ports. No external gates or latches are needed-this is intrinsic to its internal bus transceiver architecture.
Can unused inputs on the SN74ALS245ADWR be left floating?
No. All unused inputs-including DIR, OE, and any unconnected A/B port pins-must be tied to VCC or GND to ensure predictable logic states and prevent increased ICC or oscillation. TI explicitly recommends this in Application Report SCBA004 to avoid slow or floating CMOS input effects.
What is the meaning of "-1" suffix in related part numbers like SN74ALS245A-1DWR?
The "-1" suffix denotes a variant with enhanced low-level output current: IOL = 48 mA (min) instead of 24 mA (min), applicable only when VCC is 4.75 V to 5.25 V. The SN74ALS245ADWR is the standard version (24 mA IOL), not the -1 variant.
Is the SN74ALS245ADWR pin-compatible with the SN74LS245N?
Yes-the SN74ALS245ADWR is functionally and pin-compatible with the SN74LS245N in terms of pin assignment, logic behavior, and electrical interface. However, it offers faster propagation delay (10 ns vs. 15–20 ns), lower power consumption, and improved noise immunity due to ALS process enhancements.
SN74ALS245ADWR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ALS
- 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:
- 15mA, 24mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
SN74ALS245ADWR FAQ
1.How can I place an order for SN74ALS245ADWR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ALS245ADWR 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 SN74ALS245ADWR reliable?
The price and inventory of SN74ALS245ADWR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ALS245ADWR is usually 5 days.
3.What payment methods are accepted for SN74ALS245ADWR?
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4.How is shipping managed for SN74ALS245ADWR?
SN74ALS245ADWR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ALS245ADWR 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 SN74ALS245ADWR?
For technical support, including SN74ALS245ADWR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ALS245ADWR requirements.
6.How does Aetrix verify that SN74ALS245ADWR is sourced from the original manufacturer or authorized distributors?
All SN74ALS245ADWR 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 SN74ALS245ADWR meets industry standards.
7.What is the process for return or replacement of SN74ALS245ADWR?
All SN74ALS245ADWR units undergo pre-shipment inspection (PSI). If there is an issue with SN74ALS245ADWR, 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 SN74ALS245ADWR part is unused and in its original packaging.
Return procedure for SN74ALS245ADWR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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