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Texas Instruments SN74ACT245DW
- Part No.:
- SN74ACT245DW
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74ACT245DW.pdf
- Description:
- IC TXRX NON-INVERT 5.5V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:412
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Product details
Overview
SN74ACT245DW from Texas Instruments is an octal bus transceiver with 3-state outputs, designed for asynchronous bidirectional data bus communication between 5-V logic domains. It operates from 4.5 V to 5.5 V, supports TTL-compatible inputs up to 5.5 V, delivers ≤8 ns propagation delay at 5 V, and features independent direction (DIR) and output-enable (OE) controls - enabling use in industrial I/O expansion and legacy bus isolation.
For engineers reviewing the SN74ACT245DW datasheet, SN74ACT245DW pinout, SN74ACT245DW application, or SN74ACT245DW equivalent, key selection criteria include its SOIC-20 package compatibility, 24-mA drive strength per output, ±3000-V HBM ESD rating, and guaranteed operation across –40°C to +85°C industrial temperature range.
Technical Context
The SN74ACT245DW implements a dual-bus, noninverting transceiver architecture with separate DIR and OE control lines. Its function table defines three modes: A→B data flow (DIR = high, OE = low), B→A flow (DIR = low, OE = low), and high-impedance isolation (OE = high).
It uses ACT (Advanced CMOS Technology) logic with balanced output drive, slower edge rates to suppress ringing, and overvoltage-tolerant inputs that accept up to 5.5 V regardless of VCC. The device draws only 40 µA typical ICC at 5.5 V and exhibits 45 pF power dissipation capacitance at 1 MHz.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.5 V to 5.5 V - ensures compatibility with standard 5-V TTL and CMOS systems and tolerates supply ripple. |
| Max Propagation Delay | 8 ns at 5 V - enables reliable timing in high-speed parallel bus interfaces up to ~100 MHz clock-equivalent rates. |
| Output Drive | ±24 mA per pin - sufficient to drive standard 50-Ω transmission lines or multiple TTL loads without external buffers. |
| Input Voltage Tolerance | Up to 5.5 V - allows safe interfacing with mixed-voltage systems where input signals may exceed VCC. |
| ESD Rating | ±3000 V HBM - meets industrial handling requirements and reduces need for external protection circuitry. |
| Operating Temperature | –40°C to +85°C - qualified for use in factory automation, pro audio, and appliance control environments. |
| Power Dissipation Cap | 45 pF - quantifies dynamic power consumption; used with frequency and load to calculate total switching power. |
Pinout & Package
SN74ACT245DW is housed in a 20-pin SOIC (DW) package measuring 12.8 mm × 10.3 mm (body: 12.8 mm × 7.5 mm), with gull-wing leads and RoHS-compliant NiPdAu plating. It has a moisture sensitivity level (MSL) rating of Level-1 (unlimited floor life at ≤30°C/60% RH) and supports standard 260°C peak reflow.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | DIR | Direction control input: high enables A→B data flow; low enables B→A flow. |
| 2–9 | A1–A8 | Port A bidirectional I/Os - connect to source bus; driven or sensed depending on DIR and OE state. |
| 10 | GND | Ground reference for all logic and power domains - must be low-impedance and decoupled. |
| 11–18 | B8–B1 | Port B bidirectional I/Os - connect to destination bus; order reversed per TI pin diagram convention. |
| 19 | OE | Active-low output enable: low activates transceiver; high places both ports in high-Z isolation. |
| 20 | VCC | Positive supply pin - requires local 0.1-µF ceramic bypass capacitor placed within 5 mm. |
Key Features
| Feature | Design Value |
|---|---|
| Wide VCC range | 4.5 V to 5.5 V - accommodates aging power supplies and brown-out conditions without functional loss. |
| TTL-compatible inputs | VIH = 2.0 V min, VIL = 0.8 V max - ensures interoperability with legacy 5-V TTL logic families. |
| Overvoltage-tolerant inputs | Accepts up to 5.5 V regardless of VCC - eliminates need for level-shifting when interfacing with higher-voltage peripherals. |
| Controlled edge rates | Slower transitions minimize output ringing and EMI in unterminated or lightly loaded PCB traces. |
| High-impedance isolation | IOZ ≤ ±10 µA when OE = high - prevents bus contention and leakage current during system sleep or reset states. |
Applications
| Industrial PLC I/O Expansion | Pro Audio Digital Bus Isolation |
|---|---|
|
Use Scenario: Isolating microcontroller GPIO banks from noisy 5-V sensor/actuator buses in programmable logic controllers. IC Role / Device Role / Timing Role: Bidirectional level-consistent bus transceiver enabling clean signal routing between MCU and field-side peripherals. Use Value: Prevents ground loop noise coupling and bus contention via independent OE/DIR control and 24-mA drive capability. |
Use Scenario: Buffering digital audio control signals (e.g., AES3, I²S control lines) between DSP and analog stage ICs in mixing consoles. IC Role / Device Role / Timing Role: Glue logic transceiver ensuring glitch-free bidirectional register access while suppressing EMI-induced jitter. Use Value: Slower edge rates reduce radiated emissions; 8-bit width matches common audio register widths and simplifies layout. |
| Appliance Mainboard Interfacing | Factory Automation Backplane Interface |
|
Use Scenario: Connecting 3.3-V microcontroller subsystems to legacy 5-V display drivers, keypad scanners, and motor control ICs in smart appliances. IC Role / Device Role / Timing Role: Voltage-domain translator and bus driver supporting mixed-signal board partitioning without active level shifters. Use Value: Input overvoltage tolerance eliminates external clamping diodes; SOIC-20 footprint fits constrained mainboard layouts. |
Use Scenario: Enabling modular backplane communication between motion controller modules and I/O expansion cards in CNC machinery. IC Role / Device Role / Timing Role: Asynchronous bidirectional data path manager synchronizing status registers and command packets across isolated sub-systems. Use Value: High-impedance isolation during hot-swap events protects upstream logic; –40°C to +85°C rating ensures reliability in unconditioned enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LVC245A | 3.3-V only (1.65–3.6 V); lower drive (±24 mA), faster tpd (5.3 ns), smaller VSSOP/TSSOP packages available. | Requires level shifting for 5-V systems; unsuitable for direct replacement in legacy 5-V designs. | Select when migrating to 3.3-V systems or when space-constrained packaging is critical. |
| SN74ABT245 | 5-V operation (4.5–5.5 V); higher drive (±64 mA), faster tpd (3.9 ns), higher ICC (25 mA typ), no input overvoltage tolerance. | Higher power and EMI risk; lacks 5.5-V input tolerance - requires strict voltage alignment. | Choose for maximum speed and drive in noise-controlled 5-V environments where input voltage matching is guaranteed. |
Compared with SN74LVC245A and SN74ABT245, the SN74ACT245DW uniquely balances 5-V compatibility, input overvoltage safety, and controlled edge rates - making it optimal for retrofitting and industrial bus isolation where robustness outweighs raw speed.
Availability
SN74ACT245DW is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, pro audio digital bus isolation, and appliance mainboard interfacing requiring stable component supply across extended product lifecycles.
Supply support for SN74ACT245DW 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 heritage in industrial-grade interface ICs.
The SN74ACT245DW belongs to TI's legacy 74ACT logic family - engineered for robust 5-V bus interfacing in harsh environments, emphasizing noise immunity, wide supply tolerance, and long-term manufacturability.
FAQ
What is the maximum operating voltage for SN74ACT245DW?
The SN74ACT245DW supports a supply voltage range of 4.5 V to 5.5 V. Its absolute maximum VCC rating is 7 V, but sustained operation above 5.5 V violates recommended conditions and risks parametric degradation. Inputs tolerate up to 5.5 V regardless of VCC, enabling safe interfacing with overvoltage sources.
Does SN74ACT245DW support bidirectional data flow without external logic?
Yes. The SN74ACT245DW natively supports bidirectional data transfer using its dedicated DIR (direction) and OE (output enable) pins. When OE is low, setting DIR high routes data from Port A to Port B; setting DIR low routes from Port B to Port A - all without external combinational logic.
Can SN74ACT245DW be used in 3.3-V systems?
No. The SN74ACT245DW is specified only for 4.5–5.5 V operation. Its inputs are TTL-compatible but not 3.3-V logic-level compatible - applying 3.3-V signals may result in marginal VIH/VIL margins and unreliable switching. For 3.3-V systems, consider SN74LVC245A instead.
What is the thermal resistance (RθJA) of SN74ACT245DW in SOIC package?
The junction-to-ambient thermal resistance (RθJA) for SN74ACT245DW in the DW (SOIC-20) package is 98.6°C/W under standard JEDEC test conditions (1s² copper pad). This value assumes proper PCB copper pour and single-layer 2-oz copper; actual performance improves with enhanced heatsinking.
How does SN74ACT245DW prevent bus contention during power-up?
The SN74ACT245DW enters high-impedance state when OE is high. To ensure isolation during power-up/power-down, TI recommends tying OE to VCC via a pullup resistor (value determined by driver sink capability). This guarantees bus isolation before internal logic stabilizes - preventing contention on shared data lines.
SN74ACT245DW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ACT
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- 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:
- 24mA, 24mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
SN74ACT245DW FAQ
1.How can I place an order for SN74ACT245DW through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ACT245DW 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 SN74ACT245DW reliable?
The price and inventory of SN74ACT245DW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ACT245DW is usually 5 days.
3.What payment methods are accepted for SN74ACT245DW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74ACT245DW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74ACT245DW?
SN74ACT245DW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ACT245DW 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 SN74ACT245DW?
For technical support, including SN74ACT245DW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ACT245DW requirements.
6.How does Aetrix verify that SN74ACT245DW is sourced from the original manufacturer or authorized distributors?
All SN74ACT245DW 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 SN74ACT245DW meets industry standards.
7.What is the process for return or replacement of SN74ACT245DW?
All SN74ACT245DW units undergo pre-shipment inspection (PSI). If there is an issue with SN74ACT245DW, 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 SN74ACT245DW part is unused and in its original packaging.
Return procedure for SN74ACT245DW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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