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Texas Instruments CD74ACT245E
- Part No.:
- CD74ACT245E
- Manufacturer:
- Texas Instruments
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
CD74ACT245E.pdf
- Description:
- IC TXRX NON-INVERT 5.5V 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:523
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Product details
Overview
CD74ACT245E from Texas Instruments is an octal non-inverting three-state bidirectional bus transceiver used for level-shifted or isolated data path control between A- and B-bus domains in digital systems. It operates at 4.5V–5.5V, delivers ±24mA output drive, exhibits 9.1ns typical propagation delay at 5V/25°C, and supports industrial temperature range (–55°C to 125°C). It is commonly deployed in microcontroller peripheral interfacing and legacy bus arbitration circuits.
For engineers reviewing the CD74ACT245E datasheet, CD74ACT245E pinout, CD74ACT245E application, or CD74ACT245E equivalent, key selection criteria include its TTL-compatible input thresholds (VIH = 2.0V, VIL = 0.8V), high-current drive capability (±24mA), three-state enable timing (tPZL/tPHZ ≤13.1ns), and PDIP-20 package compatibility with through-hole prototyping and industrial control PCBs.
Technical Context
The CD74ACT245E implements a dual-directional 8-bit data path controlled by DIR and OE inputs, enabling A→B or B→A transmission under active-low output enable. Its ACT logic family ensures TTL-level input compatibility while maintaining CMOS power efficiency and SCR-latchup resistance.
Propagation delays are balanced across all eight channels, with tPLH/tPHL ≤10ns (5V, –40°C to 85°C) and three-state transition times (tPLZ/tPHZ ≤14ns) optimized for synchronous bus handshaking. The device features 10pF input capacitance and 15pF three-state output capacitance, minimizing signal integrity degradation in parallel bus topologies.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5V to 5.5V - Ensures reliable operation with standard 5V TTL/CMOS rails and tolerance for supply droop. |
| Propagation Delay (tPLH/tPHL) | 2.7ns typ / 10ns max at 5V - Enables high-speed data transfer in 20–30MHz bus applications. |
| Output Drive Current | ±24mA per pin - Sufficient to drive 15 FAST™ IC inputs or terminate 50Ω transmission lines directly. |
| Input Thresholds | VIH = 2.0V, VIL = 0.8V - Guarantees robust noise immunity and direct interface with TTL outputs without level shifting. |
| Operating Temperature | –55°C to +125°C - Qualified for extended industrial, automotive under-hood, and military-grade environments. |
| Three-State Leakage | ±5µA max at 5.5V - Minimizes standby current in high-density bus systems with multiple transceivers. |
| Quiescent Supply Current | 8µA typ / 160µA max - Supports low-power idle states in battery-backed or energy-conscious designs. |
Pinout & Package
CD74ACT245E is packaged in a 20-pin Plastic Dual In-line Package (PDIP-N), with 24.33mm × 9.4mm overall dimensions and 24.33mm × 6.35mm body size. The package is through-hole mountable, RoHS-compliant (NIPDAU finish), and rated for moisture sensitivity level N/A (tube packaging).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (DIR) | Direction Control Input | Determines data flow direction: DIR = LOW enables B→A; DIR = HIGH enables A→B. |
| 2–9 (A0–A7) | Port A I/O Terminals | Bidirectional data pins for A-side bus; high-impedance when OE = HIGH or DIR conflicts with active path. |
| 10 (GND) | Ground Reference | Primary return path for all internal logic and output currents; must be low-inductance connection. |
| 11–18 (B0–B7) | Port B I/O Terminals | Bidirectional data pins for B-side bus; functionally mirrored to A-port with direction determined by DIR. |
| 19 (OE) | Output Enable Input | Active-HIGH control: OE = HIGH forces all outputs into high-impedance state regardless of DIR state. |
| 20 (VCC) | Power Supply | 5V nominal supply input; requires local 0.1µF bypass capacitor adjacent to pin for noise suppression. |
Key Features
| Feature | Design Value |
|---|---|
| TTL-Compatible Inputs | VIH = 2.0V / VIL = 0.8V at 5V - Eliminates need for external level shifters when interfacing with legacy 5V TTL peripherals. |
| High-Current Drive | ±24mA per output - Supports fanout to 15 FAST™ devices or direct 50Ω line driving without external buffers. |
| SCR-Latchup Resistant | Qualified per JEDEC JESD78 - Prevents destructive latchup during voltage transients or ESD events in harsh environments. |
| Balanced Propagation Delays | tPLH ≈ tPHL within 0.2ns - Reduces skew-induced setup/hold violations in synchronous multi-bit transfers. |
| Three-State Noise Immunity | VOHV ≥4.0V / VOLP ≤1.0V during switching - Maintains clean logic levels on shared buses even during simultaneous output transitions. |
Applications
| Microcontroller Peripheral Expansion | Legacy Bus Isolation |
|---|---|
|
Use Scenario: Interfacing an 8-bit microcontroller's data bus to external SRAM, EPROM, or I/O expanders with mismatched timing or loading requirements. IC Role / Device Role / Timing Role: Bidirectional data buffer that isolates MCU timing margins from slower peripherals and prevents bus contention during read/write cycles. Use Value: Enables reliable 5V system expansion using standard address/data latching without custom glue logic or timing compensation. |
Use Scenario: Segregating two independent 5V bus segments (e.g., CPU bus and display controller bus) to prevent signal corruption during concurrent access. IC Role / Device Role / Timing Role: Direction-controlled isolation gate that blocks unintended data leakage and enforces strict bus ownership via DIR/OE coordination. Use Value: Eliminates cross-talk and metastability in multi-master systems while supporting hot-swap-safe bus arbitration. |
| Industrial PLC Backplane Interface | Test Equipment Signal Routing |
|
Use Scenario: Routing sensor data or actuator commands across modular PLC backplanes where modules operate at different voltage or timing domains. IC Role / Device Role / Timing Role: Level-consistent transceiver that maintains signal integrity across long traces and noisy industrial environments. Use Value: Provides ±24mA drive and –55°C to +125°C operation required for DIN-rail mounted controllers in factory automation. |
Use Scenario: Configurable signal path switching in automated test equipment (ATE) to route DUT signals between measurement instruments and stimulus sources. IC Role / Device Role / Timing Role: Reconfigurable bidirectional channel that supports both stimulus injection and response capture on shared test fixtures. Use Value: Reduces fixture complexity by replacing relays or multiplexers with deterministic, low-skew digital routing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ACT245N | Identical ACT logic family, same 4.5–5.5V supply, ±24mA drive, and pinout; TI second-source with identical AC/DC specs. | No functional difference; validated for identical industrial temperature range and bus-loading use cases. | Preferred for dual-sourcing assurance and extended lifecycle availability in long-term production programs. |
| 74ACT245PC | Same electrical specs but packaged in 20-pin PDIP with slightly different mechanical tolerances (body size 24.2×6.92mm vs. CD74ACT245E's 24.33×6.35mm). | Compatible for through-hole replacement; minor footprint variance requires layout verification for tight board spacing. | Select when sourcing from legacy distributors or when matching existing 74ACT-series inventory for consistency. |
Compared with SN74ACT245N and 74ACT245PC, CD74ACT245E offers identical functional behavior and timing but carries TI-specific qualification documentation, enhanced latchup immunity per JESD78, and guaranteed traceability for defense/aerospace BOMs requiring manufacturer-controlled lot traceability.
Availability
CD74ACT245E is available at Aetrix Electronics and suitable for industrial control systems, test equipment signal routing, and microcontroller peripheral expansion requiring stable component supply across extended temperature ranges and long product lifecycles.
Supply support for CD74ACT245E 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 high-reliability components.
The CD74ACT245E belongs to TI's Advanced CMOS Logic (ACT) family, engineered for TTL-compatible 5V systems demanding low power, high noise immunity, and robust operation in industrial and automotive environments.
FAQ
What is the maximum operating temperature range for the CD74ACT245E?
The CD74ACT245E is specified for continuous operation from –55°C to +125°C, making it suitable for under-hood automotive, industrial control, and military-grade applications where thermal extremes are expected. This rating is verified per JEDEC JESD22-A108 and applies across the full 4.5V–5.5V supply range.
Does the CD74ACT245E support 3.3V logic interfaces?
No, the CD74ACT245E is not designed for 3.3V operation. Its recommended supply range is strictly 4.5V–5.5V, and its TTL-compatible input thresholds (VIH = 2.0V, VIL = 0.8V) assume a 5V rail. Using it with 3.3V logic may result in marginal or non-functional input recognition and is outside datasheet specifications.
How does the DIR pin control data direction in the CD74ACT245E?
In the CD74ACT245E, the DIR pin determines bidirectional flow: when DIR = LOW, data passes from Port B (pins 11–18) to Port A (pins 2–9); when DIR = HIGH, data flows from Port A to Port B. This occurs only when OE = LOW; if OE = HIGH, both ports enter high-impedance regardless of DIR state.
What is the purpose of the OE pin on the CD74ACT245E?
The OE (Output Enable) pin on the CD74ACT245E is an active-HIGH control that places all A- and B-port outputs into a high-impedance state when asserted, effectively disconnecting the transceiver from both buses. This enables safe bus sharing among multiple devices and prevents contention during system reset or configuration changes.
Can the CD74ACT245E drive a 50Ω transmission line directly?
Yes, the CD74ACT245E is explicitly characterized to drive 50Ω transmission lines, supported by its ±24mA output drive capability and verified performance at 85°C. This allows point-to-point or short-bus routing without external line drivers in applications such as backplane interconnects or test fixture signal distribution.
CD74ACT245E Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ACT
- Package/Case:
- 20-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- 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:
- 24mA, 24mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -55°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 20-PDIP
CD74ACT245E FAQ
1.How can I place an order for CD74ACT245E through Aetrix?
Please submit a Request for Quotation (RFQ) for CD74ACT245E 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 CD74ACT245E reliable?
The price and inventory of CD74ACT245E are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CD74ACT245E is usually 5 days.
3.What payment methods are accepted for CD74ACT245E?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CD74ACT245E transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CD74ACT245E?
CD74ACT245E orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CD74ACT245E 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 CD74ACT245E?
For technical support, including CD74ACT245E datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CD74ACT245E requirements.
6.How does Aetrix verify that CD74ACT245E is sourced from the original manufacturer or authorized distributors?
All CD74ACT245E 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 CD74ACT245E meets industry standards.
7.What is the process for return or replacement of CD74ACT245E?
All CD74ACT245E units undergo pre-shipment inspection (PSI). If there is an issue with CD74ACT245E, 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 CD74ACT245E part is unused and in its original packaging.
Return procedure for CD74ACT245E:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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