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Texas Instruments CD74ACT245EE4
- Part No.:
- CD74ACT245EE4
- Manufacturer:
- Texas Instruments
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
CD74ACT245EE4.pdf
- Description:
- OCTAL NON-INVERTING BUS TRANSCEI
- Quantity:
- Payment:
- Shipping:
Inventory:2,876
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Product details
Overview
CD74ACT245EE4 from Texas Instruments is an octal non-inverting three-state bidirectional bus transceiver in 20-pin PDIP package, operating at 4.5V–5.5V supply, with 2.7ns typical propagation delay (5V, 25°C), ±24mA output drive, and TTL-compatible input thresholds. It enables controlled data flow between two 8-bit buses in industrial control backplanes and legacy microprocessor system expansion interfaces.
For engineers reviewing the CD74ACT245EE4 datasheet, CD74ACT245EE4 pinout, CD74ACT245EE4 application, or CD74ACT245EE4 equivalent, this page delivers verified electrical specs, functional mode behavior, thermal metrics for through-hole PCB layout, and validated alternatives for bus interface redesigns requiring 5V logic-level translation and bidirectional isolation.
Technical Context
The CD74ACT245EE4 implements a dual-bus bidirectional transceiver architecture with independent DIR (direction) and OE (output enable) control inputs. Its Advanced CMOS Technology ensures SCR-latchup resistance and balanced propagation delays across all eight channels.
It operates strictly within 4.5V–5.5V VCC, with VIH = 2.0V min and VIL = 0.8V max, enabling direct interfacing with TTL outputs. Three-state outputs exhibit 15pF CO and support 50Ω transmission-line driving at 85°C per TI test conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.5V to 5.5V - Ensures compatibility with standard 5V TTL/CMOS systems without level-shifting. |
| tPLH/tPHL (Typ) | 2.7ns at VCC = 5V, TA = 25°C, CL = 50pF - Enables high-speed data transfer in 20–30MHz bus applications. |
| IO Output Drive | ±24mA per pin - Sufficient to drive 15 FAST™ ICs or terminate a 50Ω transmission line directly. |
| VIH / VIL | 2.0V min / 0.8V max - Guarantees reliable recognition of TTL logic levels without external biasing. |
| ICC Quiescent | 8µA max at 25°C - Supports low-static-power operation in standby modes of embedded controllers. |
| Operating Temp | –55°C to +125°C - Qualified for extended-temperature industrial and military-grade environments. |
| Package | PDIP-20 (N), body size 24.33mm × 6.35mm - Through-hole mounting compatible with wave-solder and manual rework. |
Pinout & Package
CD74ACT245EE4 uses a 20-pin Plastic Dual In-line Package (PDIP-N) with 0.3-inch width, 24.33mm × 9.4mm overall footprint, and 24.33mm × 6.35mm body dimensions. Pin 1 is located at the left end of the top row, identified by a notch or dot.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | DIR | Direction control: LOW enables B→A data flow; HIGH enables A→B data flow. |
| 2–9 | A0–A7 | Port A bidirectional I/O pins - connect to source bus (e.g., microprocessor data bus). |
| 10 | GND | Ground reference for all logic and power domains. |
| 11–18 | B0–B7 | Port B bidirectional I/O pins - connect to destination bus (e.g., peripheral or memory bus). |
| 19 | OE | Output enable: LOW activates transceiver; HIGH places all A/B pins in high-impedance state. |
| 20 | VCC | Positive supply input - must be bypassed with 0.1µF ceramic capacitor near pin. |
Key Features
| Feature | Design Value |
|---|---|
| Three-state bidirectional operation | Enables time-multiplexed bus sharing between two 8-bit subsystems without contention or external arbitration logic. |
| SCR-latchup-resistant process | Prevents destructive latch-up under transient overvoltage or ESD events in harsh industrial environments. |
| ±24mA output drive | Eliminates need for external buffer stages when driving heavy capacitive loads or multiple TTL inputs. |
| Buffered inputs | Reduces input loading on upstream drivers and improves noise immunity on long trace runs. |
| 15pF output capacitance (CO) | Minimizes switching-induced crosstalk and supports clean signal integrity on densely routed PCBs. |
Applications
| Industrial Backplane Interface | Legacy Microprocessor Expansion |
|---|---|
|
Use Scenario: Interfacing a 80C88 CPU data bus to modular I/O cards in programmable logic controller (PLC) chassis. IC Role / Device Role / Timing Role: Bidirectional data path isolator with direction control synchronized to CPU address strobes. Use Value: Eliminates bus contention during read/write cycles and supports hot-swap capability via OE-controlled high-Z state. |
Use Scenario: Adding external RAM or EPROM to Z80-based embedded instrumentation systems. IC Role / Device Role / Timing Role: Data bus transceiver managing bidirectional transfers between Z80 D0–D7 and memory device data lines. Use Value: Matches Z80 timing requirements with sub-3ns propagation delay and TTL-compatible input thresholds. |
| Test Equipment Bus Arbitration | Automated Test Fixture Control |
|
Use Scenario: Sharing GPIB or IEEE-488 data lines among multiple instrument modules in benchtop ATE systems. IC Role / Device Role / Timing Role: Controlled bus switch enabling one module at a time to drive the shared parallel bus. Use Value: Prevents signal collisions using DIR/OE logic coordinated by master controller firmware. |
Use Scenario: Isolating microcontroller GPIOs from relay driver banks and sensor multiplexers in production test fixtures. IC Role / Device Role / Timing Role: Level-translating and current-boosting interface between 5V MCU and 12V/24V actuator circuits. Use Value: Provides robust 24mA sink/source per line to directly drive optocoupler inputs without discrete transistors. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ACT245N | Same ACT logic family, identical pinout and AC specs; TI's newer second-source marking with identical PDIP-20 packaging. | Functionally interchangeable; preferred for new designs due to active production status and broader distributor availability. | Select SN74ACT245N when sourcing new production builds requiring guaranteed long-term supply and full TI technical support. |
| 74ACT245PC | Identical electrical specs and pinout; manufactured by ON Semiconductor in PDIP-20, RoHS-compliant with NIPDAU finish. | Valid drop-in replacement where cross-supplier qualification is required; same thermal resistance (RθJA = 69°C/W). | Choose 74ACT245PC for multi-source procurement strategies or when TI part allocation constraints arise. |
Compared with CD74ACT245EE4, SN74ACT245N offers identical performance with enhanced supply chain visibility, while 74ACT245PC provides a fully qualified second-source option with matching thermal and timing behavior-both eliminate redesign effort when substituting into existing PDIP-20 layouts.
Availability
CD74ACT245EE4 is available at Aetrix Electronics and suitable for industrial backplane interfaces, legacy microprocessor expansions, and automated test fixture control requiring stable component supply across extended temperature ranges and long product lifecycles.
Supply support for CD74ACT245EE4 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 aerospace electronics.
The CD74ACT245EE4 belongs to TI's Advanced CMOS Logic (ACT) family, engineered for high-speed, low-power 5V bus interfacing in mission-critical industrial and defense systems requiring latch-up immunity and wide temperature operation.
FAQ
What is the maximum operating voltage for CD74ACT245EE4?
The CD74ACT245EE4 has an absolute maximum VCC rating of 6V, but its recommended operating range is strictly 4.5V to 5.5V per TI's datasheet Section 4.2. Operating outside this window risks violating input threshold specifications and may degrade propagation delay consistency or increase quiescent current beyond rated limits.
Does CD74ACT245EE4 support bidirectional data flow on the same pin pairs?
Yes, CD74ACT245EE4 supports true bidirectional operation on each A/B pin pair (e.g., A0↔B0). Direction is controlled solely by the DIR pin: when DIR = LOW, data flows from Port B to Port A; when DIR = HIGH, data flows from Port A to Port B - all under OE = LOW activation.
Can CD74ACT245EE4 drive a 50Ω transmission line directly?
Yes, CD74ACT245EE4 is explicitly characterized to drive a 50Ω transmission line at 85°C per TI test condition (Section 4.4 footnote 1), supported by its ±24mA output drive capability and low VOL/VOLP values - no external line driver is required for point-to-point 50Ω traces up to ~15cm.
What is the thermal resistance (RθJA) of CD74ACT245EE4 in PDIP package?
The CD74ACT245EE4 in PDIP-20 (N) package has a junction-to-ambient thermal resistance (RθJA) of 69°C/W, as specified in Section 4.3 of the TI datasheet. This value assumes standard JEDEC 2S2P test board conditions and informs heatsinking requirements for continuous high-current operation.
Is CD74ACT245EE4 pin-compatible with CD74AC245EE4?
No, CD74ACT245EE4 is not pin-compatible with CD74AC245EE4 in functional operation: although both share identical pinouts and package, their input thresholds differ (ACT: VIH = 2.0V, VIL = 0.8V; AC: VIH = 3.85V at 5.5V). Swapping them risks logic misreads unless supply and interface voltages are revalidated.
CD74ACT245EE4 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
CD74ACT245EE4 FAQ
1.How can I place an order for CD74ACT245EE4 through Aetrix?
Please submit a Request for Quotation (RFQ) for CD74ACT245EE4 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 CD74ACT245EE4 reliable?
The price and inventory of CD74ACT245EE4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CD74ACT245EE4 is usually 5 days.
3.What payment methods are accepted for CD74ACT245EE4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CD74ACT245EE4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CD74ACT245EE4?
CD74ACT245EE4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CD74ACT245EE4 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 CD74ACT245EE4?
For technical support, including CD74ACT245EE4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CD74ACT245EE4 requirements.
6.How does Aetrix verify that CD74ACT245EE4 is sourced from the original manufacturer or authorized distributors?
All CD74ACT245EE4 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 CD74ACT245EE4 meets industry standards.
7.What is the process for return or replacement of CD74ACT245EE4?
All CD74ACT245EE4 units undergo pre-shipment inspection (PSI). If there is an issue with CD74ACT245EE4, 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 CD74ACT245EE4 part is unused and in its original packaging.
Return procedure for CD74ACT245EE4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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