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Texas Instruments CD74AC245EG4
- Part No.:
- CD74AC245EG4
- Manufacturer:
- Texas Instruments
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
CD74AC245EG4.pdf
- Description:
- IC TXRX NON-INVERT 5.5V 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:3,000
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Product details
Overview
CD74AC245EG4 from Texas Instruments is an octal non-inverting three-state bidirectional bus transceiver in 20-pin PDIP (N) package, operating from 1.5V to 5.5V, delivering ±24mA output drive and 4ns typical propagation delay at 5V/25°C/50pF - used for level-shifting and bus isolation in industrial control backplanes and legacy data acquisition systems.
For engineers reviewing the CD74AC245EG4 datasheet, CD74AC245EG4 pinout, CD74AC245EG4 application, or CD74AC245EG4 equivalent, this page provides verified functional modes, thermal metrics, switching characteristics across temperature ranges, and validated alternatives for bus interface redesigns requiring CMOS-compatible drive strength and wide VCC tolerance.
Technical Context
The CD74AC245EG4 implements a dual-bus transceiver architecture with DIR-controlled directionality and OE-gated three-state outputs. Its Advanced CMOS Logic process ensures SCR-latchup resistance and balanced tPLH/tPHL delays under varying load conditions.
It supports mixed-voltage interfacing via 1.5V–5.5V operation, with input thresholds scaled to 30% of VCC for robust noise immunity. Output enable timing (tPLZ/tPHZ ≤175ns at −55°C to 125°C) and simultaneous switching transient suppression (VOHV ≥4V, VOLP ≤1V at 5V) are specified across full military temperature range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 1.5V to 5.5V - enables interoperability between 3.3V and 5V logic domains without level shifters |
| Propagation Delay (tPLH/tPHL) | 4ns typical at 5V/25°C/50pF - supports >100MHz bus toggle rates in short-line applications |
| Output Drive | ±24mA per pin - drives 50Ω transmission lines directly and fans out to 15 FAST™ ICs |
| Three-State Leakage (IOZ) | ±10µA max at −55°C to 125°C - ensures low standby current in high-density bus hold configurations |
| Input Thresholds | VIH = 0.7×VCC, VIL = 0.3×VCC - provides 30% noise margin across full supply range |
| Quiescent ICC | 160µA max at −55°C to 125°C - minimizes static power in always-on control subsystems |
Pinout & Package
CD74AC245EG4 is supplied in a 20-pin plastic dual in-line package (PDIP, N), body size 24.33mm × 6.35mm, with 2.54mm lead pitch and through-hole mounting.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (DIR) | Direction control input | High = A→B data flow; Low = B→A data flow; determines active bus path during OE enable |
| 10 (GND) | Ground reference | Primary return path for all I/O and internal logic; must be low-impedance connection to system ground plane |
| 19 (OE) | Output enable input | Active-Low: OE = Low enables transceiver; OE = High forces all outputs into high-impedance state |
| 20 (VCC) | Power supply | Single 1.5V–5.5V supply for entire device; requires local 0.1µF bypass capacitor per VCC pin |
| 2–9, 11–18 (A0–A7, B0–B7) | Bidirectional I/O ports | Octal A-side and B-side buses; each pin functions as input or output depending on DIR and OE states |
Key Features
| Feature | Design Value |
|---|---|
| Buffered inputs | Reduces capacitive loading on upstream drivers and improves signal integrity in fanout-heavy bus topologies |
| SCR-latchup-resistant process | Guarantees immunity to latchup under overvoltage transients up to ±20mA input diode current |
| Balanced propagation delays | tPLH and tPHL match within 0.2ns typical - eliminates skew-induced setup/hold violations in synchronous bus transfers |
| Wide temperature operation | Specified from −55°C to +125°C - suitable for under-hood automotive ECUs and industrial PLC modules |
| Transmission-line drive capability | Validated 50Ω line drive at 85°C - enables direct connection to unterminated PCB traces up to 15cm without termination resistors |
Applications
| Industrial Backplane Interface | Legacy Data Acquisition System |
|---|---|
Use Scenario: Isolating microcontroller GPIO banks from noisy 24V I/O expansion modules in programmable logic controllers. IC Role / Device Role / Timing Role: Bidirectional level-shifting transceiver managing data flow between 3.3V MCU and 5V peripheral bus with direction controlled by firmware. Use Value: Eliminates need for discrete level translators while maintaining <4ns timing margin for 20MHz parallel bus handshaking. |
Use Scenario: Interfacing aging 8-bit ADC/DAC cards to modern FPGA-based controller boards in test equipment racks. IC Role / Device Role / Timing Role: Bus buffer isolating legacy TTL/CMOS cards from FPGA I/O banks, with OE synchronized to DMA strobes. Use Value: Provides ±24mA drive to overcome long trace capacitance and ensures clean three-state release during card hot-swap sequences. |
| Military Vehicle Control Unit | Automated Test Equipment (ATE) |
Use Scenario: Signal routing between radiation-hardened processor modules and sensor interface cards in armored vehicle avionics. IC Role / Device Role / Timing Role: Ruggedized bus transceiver enabling bidirectional diagnostics and configuration data exchange across isolated power domains. Use Value: SCR-latchup resistance and −55°C to +125°C operation ensure reliability in uncontrolled environmental enclosures. |
Use Scenario: Channel multiplexing and signal conditioning in modular ATE mainframes handling mixed-voltage DUT interfaces. IC Role / Device Role / Timing Role: Pin-multiplexed bus repeater synchronizing pattern generator outputs with multiple DUT sites using shared DIR/OE control. Use Value: Balanced tPLZ/tPHZ delays (<175ns worst-case) guarantee deterministic channel switching timing across temperature extremes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74AC245N | Identical AC logic family, same 20-pin PDIP package, but TI's commercial-grade variant with −40°C to +85°C rating | Lacks extended −55°C to +125°C qualification; not suitable for military or under-hood automotive use | Select SN74AC245N only for cost-sensitive commercial systems where extended temperature is unnecessary |
| 74AC245PC | Second-source version from ON Semiconductor; identical pinout and DC specs, but tPLH/tPHL max 10.8ns at 3V (vs. 11.9ns for CD74AC245EG4) | Same functional behavior, but slightly tighter propagation delay distribution at mid-supply voltages | Choose 74AC245PC when tighter delay consistency at 3.3V operation is required and sourcing diversity is desired |
Compared with SN74AC245N and 74AC245PC, CD74AC245EG4 uniquely supports full military temperature range and includes TI-specific SCR-latchup hardening - making it the only option qualified for safety-critical embedded control where ambient extremes and ESD robustness are mandatory.
Availability
CD74AC245EG4 is available at Aetrix Electronics and suitable for industrial backplane interfaces, legacy data acquisition upgrades, military vehicle control units, and automated test equipment requiring stable component supply across extended temperature and long lifecycle programs.
Supply support for CD74AC245EG4 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 50 years of innovation in industrial, automotive, and aerospace markets.
The CD74AC245EG4 belongs to TI's Advanced CMOS Logic (AC) family, engineered for high-speed, low-power bidirectional bus interfacing in harsh environments where reliability across extreme temperatures and voltage domains is critical.
FAQ
What is the maximum operating temperature range for CD74AC245EG4?
The CD74AC245EG4 is rated for operation from −55°C to +125°C, fully qualified to military temperature specifications. This range is confirmed in Section 4.2 of the official TI datasheet SCHS245D and applies to all electrical and switching characteristics including propagation delay, output drive, and three-state leakage. The CD74AC245EG4 maintains ±24mA drive capability and <175ns disable/enable delays across this full range.
Does CD74AC245EG4 support 3.3V-only operation?
Yes, CD74AC245EG4 supports 3.3V-only operation with guaranteed performance: VIH = 2.1V min, VIL = 0.9V max, VOH = 2.9V min at −40°C to +85°C, and tPLH/tPHL = 3.2ns typical at 3.3V/25°C/50pF. Its 1.5V–5.5V VCC range allows direct integration into 3.3V systems without level translation, and input thresholds scale to 30% of supply for consistent noise immunity.
How does the DIR pin control data flow in CD74AC245EG4?
In CD74AC245EG4, the DIR pin determines real-time bidirectional data path: when DIR = Low, data flows from B-bus (pins 11–18) to A-bus (pins 2–9); when DIR = High, data flows from A-bus to B-bus. This occurs only when OE = Low; if OE = High, both buses are isolated regardless of DIR state. The function table in Section 6.3 of the datasheet confirms this behavior with no internal latching.
What is the recommended bypass capacitor for CD74AC245EG4?
Texas Instruments recommends a 0.1µF ceramic bypass capacitor placed as close as possible to the VCC (pin 20) and GND (pin 10) pins of CD74AC245EG4. This value is specified in Section 7.1 for single-supply devices and is validated to suppress high-frequency noise generated during simultaneous switching of multiple outputs. For systems with multiple VCC connections, 0.01µF–0.022µF per pin is advised, but CD74AC245EG4 uses only one VCC pin.
Is CD74AC245EG4 pin-compatible with CD74ACT245E?
No, CD74AC245EG4 is not pin-compatible with CD74ACT245E in functional operation despite identical pinout and package. The ACT variant uses TTL-compatible input thresholds (VIH = 2.0V, VIL = 0.8V at 5V), while CD74AC245EG4 uses CMOS thresholds (VIH = 3.85V, VIL = 1.65V at 5.5V). Swapping them risks logic misreads unless supply and interface voltages are strictly matched to each family's specification.
CD74AC245EG4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AC
- Package/Case:
- 20-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Discontinued at Digi-Key
- 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:
- 1.5V ~ 5.5V
- Operating Temperature:
- -55°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 20-PDIP
CD74AC245EG4 FAQ
1.How can I place an order for CD74AC245EG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for CD74AC245EG4 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 CD74AC245EG4 reliable?
The price and inventory of CD74AC245EG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CD74AC245EG4 is usually 5 days.
3.What payment methods are accepted for CD74AC245EG4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CD74AC245EG4 transactions.
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4.How is shipping managed for CD74AC245EG4?
CD74AC245EG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CD74AC245EG4 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 CD74AC245EG4?
For technical support, including CD74AC245EG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CD74AC245EG4 requirements.
6.How does Aetrix verify that CD74AC245EG4 is sourced from the original manufacturer or authorized distributors?
All CD74AC245EG4 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 CD74AC245EG4 meets industry standards.
7.What is the process for return or replacement of CD74AC245EG4?
All CD74AC245EG4 units undergo pre-shipment inspection (PSI). If there is an issue with CD74AC245EG4, 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 CD74AC245EG4 part is unused and in its original packaging.
Return procedure for CD74AC245EG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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