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Texas Instruments CD74AC240EG4
- Part No.:
- CD74AC240EG4
- Manufacturer:
- Texas Instruments
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
CD74AC240EG4.pdf
- Description:
- IC BUFF INVERT 5.5V 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,783
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Product details
Overview
CD74AC240EG4 from Texas Instruments is an octal 3-state inverting buffer/line driver in a 20-pin PDIP package, operating from 1.5 V to 5.5 V, delivering ±24 mA output drive per channel, with balanced propagation delays (e.g., 6.5 ns max tPHL at 5 V), and designed for bus interface and data routing in industrial control systems.
For engineers reviewing the CD74AC240EG4 datasheet, CD74AC240EG4 pinout, CD74AC240EG4 application, or CD74AC240EG4 equivalent, key selection criteria include its dual active-low output enables (1OE, 2OE), 50-Ω transmission-line drive capability, SCR-latch-up-resistant CMOS process, and compatibility with FAST logic fanout requirements.
Technical Context
The CD74AC240EG4 implements two independent 4-bit inverting buffer banks, each controlled by its own active-low output enable (1OE for Bank 1, 2OE for Bank 2). Its RCA Advanced CMOS process ensures TTL-compatible input thresholds and rail-to-rail output swing across the full 1.5–5.5 V supply range.
It supports high-speed digital interfacing with 9.2 ns typical propagation delay (tPLH) at 3.3 V, 10 pF input capacitance, and 15 pF 3-state output capacitance - enabling clean signal integrity in multi-drop bus environments and synchronous data transfer between mixed-voltage subsystems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 1.5 V to 5.5 V - enables interoperability with 1.8 V, 3.3 V, and 5 V logic domains without level shifters |
| Output Drive | ±24 mA per output - sufficient to directly drive 50 Ω transmission lines or fan out to 15 FAST ICs |
| Propagation Delay | 6.5 ns max tPHL at 5 V - supports >100 MHz bus timing margins in noise-resilient industrial designs |
| Input Threshold | VIL = 0.9 V, VIH = 2.1 V at 3 V - provides 30% noise margin relative to supply, ensuring robust operation under EMI |
| Quiescent Current | 80 μA max ICC at +85°C - enables low-static-power operation in always-on monitoring circuits |
| ESD Rating | SCR-latch-up-resistant design - meets JEDEC JESD78 Class II latch-up immunity (>100 mA) |
Pinout & Package
CD74AC240EG4 is supplied in a 20-pin plastic dual-in-line package (PDIP-N), body size 24.33 mm × 6.35 mm, with through-hole mounting and industry-standard pin spacing (2.54 mm).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1OE, 2OE | Active-low output enable inputs | Independent control of Bank 1 (pins 2,4,6,8 → 18,16,14,12) and Bank 2 (pins 11,13,15,17 → 3,5,7,9); both must be low for output assertion |
| 1A0–1A3, 2A0–2A3 | Input channels | Eight total inputs: four per bank; all inverted on output (e.g., 1A0 → 1Y0) |
| 1Y0–1Y3, 2Y0–2Y3 | Inverting buffered outputs | Eight complementary outputs; high-impedance state when respective OE is high |
| VCC, GND | Power terminals | Single-supply operation; requires local 0.1 µF bypass capacitor at VCC pin for stable switching |
Key Features
| Feature | Design Value |
|---|---|
| Inverting 3-state buffer architecture | Enables bidirectional bus control with deterministic high-Z isolation between upstream/downstream logic domains |
| Balanced tPLH/tPHL propagation | Minimizes duty-cycle distortion in clock distribution or data strobe paths where edge symmetry matters |
| 1.5–5.5 V wide supply range | Eliminates need for separate voltage regulators in mixed-signal systems integrating analog sensors and digital controllers |
| ±24 mA drive into 50 Ω | Supports point-to-point or short stub bus topologies without external line drivers in PLC backplane interfaces |
| SCR-latch-up resistance | Guarantees immunity to transient-induced parasitic thyristor conduction in electrically noisy factory-floor environments |
Applications
| Industrial Bus Interface | Microcontroller I/O Expansion |
|---|---|
Use Scenario: Isolating and driving parallel address/data buses between a main controller and multiple peripheral modules in a programmable logic controller rack. IC Role / Device Role / Timing Role: Inverting 3-state buffer providing direction-controlled signal conditioning and noise-immune transmission over 10–20 cm PCB traces. Use Value: Enables reliable 8-bit data handshaking at up to 20 MHz while maintaining signal integrity via matched drive strength and controlled edge rates. | Use Scenario: Expanding GPIO count of an ARM Cortex-M4 microcontroller to manage LED arrays, relay banks, and sensor readouts in a building automation node. IC Role / Device Role / Timing Role: Level-shifting and current-boosting buffer translating 3.3 V MCU outputs to drive 5 V logic inputs or discrete loads. Use Value: Delivers ±24 mA per channel without external transistors, reducing BOM count and PCB area versus discrete solutions. |
| Test Equipment Signal Routing | Digital Audio Data Multiplexing |
Use Scenario: Switching test signals between multiple instrument channels in automated test equipment (ATE) using FPGA-controlled enable lines. IC Role / Device Role / Timing Role: High-isolation 3-state switch enabling glitch-free reconfiguration of signal paths during runtime. Use Value: Achieves <15 ns output disable time (tPHZ), minimizing signal contention windows during dynamic routing changes. | Use Scenario: Multiplexing I²S or SPDIF audio data streams from multiple codecs onto a shared serial bus in professional audio mixers. IC Role / Device Role / Timing Role: Low-skew inverting repeater preserving signal timing alignment across eight parallel data lanes. Use Value: Balanced propagation delays (<0.9 ns skew between channels) prevent inter-channel jitter accumulation in multi-channel digital audio paths. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal inverting buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74AC240N | Same AC logic family, identical pinout and DC specs; TI's newer second-source marking with identical DW/N package options | No functional difference; fully interchangeable in legacy and new designs | Select when sourcing from distributors with updated TI part numbering or requiring latest manufacturing lot traceability |
| 74VHC240N | Higher VCC max (5.5 V same), but lower drive (±8 mA), slower propagation (~12 ns), and no guaranteed 50 Ω line drive | Suitable only for low-speed, low-current local buffering - not for transmission-line or FAST-fanout use cases | Choose only if cost sensitivity outweighs performance needs and system timing budget allows ≥2× delay margin |
Compared with SN74AC240N, CD74AC240EG4 offers identical functionality and drop-in compatibility; versus 74VHC240N, it delivers 3× higher drive strength and sub-10 ns timing - critical for industrial bus reliability and high-fanout signal integrity.
Availability
CD74AC240EG4 is available at Aetrix Electronics and suitable for industrial control systems, test equipment signal routing, and microcontroller I/O expansion requiring stable component supply, long-term lifecycle support, and RoHS-compliant through-hole assembly.
Supply support for CD74AC240EG4 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 for industrial, automotive, and communications markets.
The CD74AC240EG4 belongs to TI's legacy CD74AC high-speed CMOS logic family, engineered for robust, low-power, wide-supply-range interfacing in harsh industrial environments where reliability and noise immunity are paramount.
FAQ
What is the maximum operating temperature range for CD74AC240EG4?
The CD74AC240EG4 is rated for operation from −40°C to +85°C, matching the commercial/industrial temperature grade of the CD74AC series. This range is validated per TI's recommended operating conditions and supported by thermal metrics including RθJA = 40°C/W for the PDIP package.
Does CD74AC240EG4 support 1.8 V logic interfacing?
Yes, CD74AC240EG4 supports 1.8 V logic interfacing: its 1.5 V to 5.5 V supply range includes 1.8 V operation, and input thresholds scale with VCC (e.g., VIH ≈ 0.7×VCC), ensuring reliable recognition of 1.8 V signals when powered at 1.8 V or higher.
Is CD74AC240EG4 pin-compatible with CD74ACT240E?
Yes, CD74AC240EG4 is pin-compatible with CD74ACT240E - both use the same 20-pin PDIP package and identical pin configuration. However, CD74ACT240E operates only from 4.5 V to 5.5 V and exhibits faster propagation delays (7.8 ns typ), making it unsuitable for sub-4.5 V systems where CD74AC240EG4 remains functional.
What is the purpose of the two separate output enables (1OE and 2OE) on CD74AC240EG4?
The two active-low output enables (1OE and 2OE) on CD74AC240EG4 independently control two 4-bit inverting buffer banks - allowing selective activation of Bank 1 (inputs 1A0–1A3 → outputs 1Y0–1Y3) or Bank 2 (inputs 2A0–2A3 → outputs 2Y0–2Y3), enabling flexible bus segmentation and partial resource gating in multi-peripheral systems.
Can CD74AC240EG4 drive 50 Ω transmission lines reliably?
Yes, CD74AC240EG4 is explicitly characterized to drive 50 Ω transmission lines: its ±24 mA output drive capability meets the minimum requirement for 50 Ω termination at 5 V (requiring ≥20 mA), and TI's datasheet confirms this capability is verified at +85°C per Section 4.4 Note (2).
CD74AC240EG4 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:
- Buffer, Inverting
- Number of Elements:
- 2
- Number of Bits per Element:
- 4
- Input Type:
- -
- Output Type:
- 3-State
- Current - Output High, Low:
- 24mA, 24mA
- Voltage - Supply:
- 1.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 20-PDIP
CD74AC240EG4 FAQ
1.How can I place an order for CD74AC240EG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for CD74AC240EG4 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 CD74AC240EG4 reliable?
The price and inventory of CD74AC240EG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CD74AC240EG4 is usually 5 days.
3.What payment methods are accepted for CD74AC240EG4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CD74AC240EG4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CD74AC240EG4?
CD74AC240EG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CD74AC240EG4 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 CD74AC240EG4?
For technical support, including CD74AC240EG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CD74AC240EG4 requirements.
6.How does Aetrix verify that CD74AC240EG4 is sourced from the original manufacturer or authorized distributors?
All CD74AC240EG4 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 CD74AC240EG4 meets industry standards.
7.What is the process for return or replacement of CD74AC240EG4?
All CD74AC240EG4 units undergo pre-shipment inspection (PSI). If there is an issue with CD74AC240EG4, 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 CD74AC240EG4 part is unused and in its original packaging.
Return procedure for CD74AC240EG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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