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Texas Instruments CD74ACT240M
- Part No.:
- CD74ACT240M
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
CD74ACT240M.pdf
- Description:
- IC BUFF INVERT 5.5V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,700
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Product details
Overview
CD74ACT240M from Texas Instruments is an octal 3-state inverting buffer/line driver IC used for bus interface and signal isolation in digital systems. It features ±24mA output drive, 5V supply operation (4.5–5.5V), 7.8ns typical propagation delay at 5V, and operates across –40°C to +85°C. It is commonly deployed in industrial control backplanes and memory address/data bus buffering.
For engineers reviewing the CD74ACT240M datasheet, CD74ACT240M pinout, CD74ACT240M application, or CD74ACT240M equivalent, key selection criteria include its active-low dual bank enable architecture, TTL-compatible inputs, 50Ω transmission-line drive capability, and SOIC-20 package compatibility with high-density PCB layouts.
Technical Context
The CD74ACT240M implements two independent 4-bit inverting buffer banks, each controlled by a dedicated active-low output enable (1OE, 2OE). Its ACT-series CMOS design ensures TTL-level input thresholds (VIH = 2.0V min, VIL = 0.8V max) and rail-to-rail output swing under load.
It delivers balanced tPLH/tPHL propagation delays (2.3–7.8ns), fast 3-state enable/disable times (3.5–12.2ns), and supports simultaneous switching noise mitigation via VOHV (4.0V typ) and VOLP (1.0V typ) specifications - critical for stable bus arbitration in multi-driver environments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5V to 5.5V - ensures compatibility with standard 5V TTL/CMOS logic rails and robust noise margin. |
| Output Drive | ±24mA per pin - enables direct fanout to 15 FAST ICs or driving 50Ω transmission lines without external buffers. |
| Propagation Delay | 7.8ns max (tPHL, 5V, –40°C to +85°C) - supports >100MHz bus timing in synchronous digital interfaces. |
| Input Thresholds | VIH = 2.0V min, VIL = 0.8V max - guarantees reliable interfacing with legacy TTL outputs and mixed-voltage system inputs. |
| 3-State Leakage | ±5μA max (IOZ, TA = –40°C to +85°C) - minimizes bus contention current during high-impedance state in shared-bus architectures. |
| Operating Temp | –40°C to +85°C - qualified for industrial-grade embedded control, instrumentation, and automation equipment. |
| Power Dissipation Cap | 65pF (CPD) - used to calculate dynamic power: PD = VCC² × fi × (CPD + CL), enabling accurate thermal budgeting. |
Pinout & Package
CD74ACT240M is housed in a 20-pin SOIC (DW) package measuring 12.8mm × 10.3mm (including pins), with body size 12.8mm × 7.5mm. The package is RoHS-compliant, lead-finish NIPDAU, MSL Level-1, and rated for –40°C to +85°C operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1OE, 2OE | Active-low bank enable inputs | Independently disable Bank 1 (pins 2,4,6,8 → 18,16,14,12) or Bank 2 (pins 11,13,15,17 → 3,5,7,9); both low required for full output activation. |
| 1A0–1A3, 2A0–2A3 | Input terminals | Eight buffered data inputs split across two 4-bit banks; all TTL-compatible with hysteresis-free thresholds. |
| 1Y0–1Y3, 2Y0–2Y3 | Inverting output terminals | Eight complementary outputs - each inverts its corresponding input; high-Z when respective OE is high. |
| GND (Pin 10), VCC (Pin 20) | Power terminals | Dual-supply reference points; requires local 0.1µF bypass capacitor at VCC for stable switching performance. |
Key Features
| Feature | Design Value |
|---|---|
| SCR latch-up resistance | Guaranteed immunity to latch-up per JEDEC JESD78, enabling reliable operation in noisy industrial environments. |
| Balanced propagation delays | tPLH and tPHL match within 0.5ns (5V), minimizing skew-induced timing violations in parallel data paths. |
| 50Ω transmission-line drive | Validated at +85°C - eliminates need for external series termination resistors in high-speed backplane routing. |
| TTL-compatible input thresholds | VIH = 2.0V / VIL = 0.8V at 5V - ensures interoperability with legacy 74LS, 74F, and microcontroller GPIOs without level-shifting. |
| Low quiescent current | ICC ≤ 80μA (max, TA = –40°C to +85°C) - reduces standby power in battery-backed or energy-sensitive control modules. |
Applications
| Industrial Backplane Interface | Memory Address Buffering |
|---|---|
Use Scenario: Isolating and driving address/data signals between CPU and peripheral cards in modular PLC chassis. IC Role / Device Role / Timing Role: Octal inverting buffer with dual 3-state enables provides directional bus control and prevents signal contention during card hot-swap. Use Value: ±24mA drive sustains signal integrity over 15cm ribbon-cable runs; 7.8ns delay aligns with 10MHz bus clock timing budgets. | Use Scenario: Buffering 8-bit address lines from microcontroller to external SRAM or EPROM in embedded instrumentation. IC Role / Device Role / Timing Role: Inverting line driver with TTL-compatible inputs translates MCU GPIO levels to memory address bus requirements while adding drive strength. Use Value: Balanced tPLH/tPHL ensures setup/hold time compliance; 50Ω drive eliminates reflections on 2-layer PCB traces up to 10cm. |
| Test Equipment Signal Routing | Digital I/O Expansion Module |
Use Scenario: Multiplexing and conditioning digital stimulus signals in automated test equipment (ATE) channel cards. IC Role / Device Role / Timing Role: 3-state buffer enables dynamic reconfiguration of signal paths under FPGA control; inverting logic accommodates polarity inversion needs. Use Value: Low IOZ (±5μA) prevents leakage-induced false triggering; VOHV/VOLP specs ensure clean edges during simultaneous switching of adjacent channels. | Use Scenario: Expanding GPIO count in programmable logic controllers using isolated 8-bit bidirectional data latches. IC Role / Device Role / Timing Role: Dual-bank enable allows independent control of input capture vs. output drive sections in half-duplex I/O expansion. Use Value: –40°C to +85°C rating supports operation inside sealed enclosures; SCR-latch-up resistance withstands ESD events common in field wiring. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal 3-state inverting buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ACT240N | Same electrical specs; PDIP-20 package (24.33mm × 9.4mm), through-hole mounting, higher RθJA (40°C/W). | Suitable for prototyping, low-volume boards, or legacy through-hole designs where SOIC reflow is unavailable. | Select SN74ACT240N only when manual assembly or socket-based testing is required; not recommended for high-density SMT production. |
| CD74ACT240M96 | Identical die and SOIC-20 package; differs only in tape-and-reel packaging (2000 pcs/reel vs. tube for CD74ACT240M). | Optimized for automated pick-and-place manufacturing; same thermal, electrical, and mechanical behavior as CD74ACT240M. | CD74ACT240M96 is functionally identical and preferred for volume SMT production; CD74ACT240M is typically supplied in tubes for sampling or small-batch use. |
Compared with SN74ACT240N and CD74ACT240M96, CD74ACT240M offers identical core functionality in SOIC-20 but with tube packaging - making it ideal for engineering validation and low-run builds where reel changeover overhead is prohibitive, while maintaining full drop-in compatibility with both alternatives in circuit design.
Availability
CD74ACT240M is available at Aetrix Electronics and suitable for industrial control backplanes, memory address buffering, and digital I/O expansion modules requiring stable component supply and long-term industrial temperature support.
Supply support for CD74ACT240M 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 CD74ACT240M belongs to TI's legacy Advanced CMOS (ACT) logic family, engineered for high-speed, low-power 5V digital interfacing with robust noise immunity and bus-driving capability in harsh operating environments.
FAQ
What is the maximum operating temperature range for the CD74ACT240M?
The CD74ACT240M is rated for operation from –40°C to +85°C, qualifying it for industrial-grade applications including programmable logic controllers, motor drives, and factory automation equipment where ambient temperatures exceed commercial limits. This range is confirmed in Section 4.2 of the TI datasheet SCHS287C.
Does the CD74ACT240M support 3.3V logic inputs?
No, the CD74ACT240M does not reliably accept 3.3V logic inputs. Its ACT-series input thresholds require VIH ≥ 2.0V and VIL ≤ 0.8V at 5V supply; a 3.3V high signal falls below the guaranteed VIH minimum and may result in marginal or undefined switching. For mixed-voltage systems, level translation is required before applying 3.3V signals to CD74ACT240M inputs.
Can the CD74ACT240M drive a 50Ω transmission line directly?
Yes, the CD74ACT240M is explicitly characterized for 50Ω transmission-line drive at +85°C (Section 4.5, Note 2), delivering ±24mA output current sufficient to maintain signal integrity without external series termination. This capability is validated per JEDEC standards and eliminates added components in high-speed backplane or cable-driver designs.
What is the function of pins 1OE and 2OE on the CD74ACT240M?
Pins 1OE and 2OE are active-low output enable controls for independent 4-bit banks: 1OE governs outputs 1Y0–1Y3 (pins 18,16,14,12), and 2OE governs outputs 2Y0–2Y3 (pins 3,5,7,9). When either is high, its associated bank enters high-impedance state; both must be low for normal inverting buffer operation - enabling flexible bus arbitration and multi-drop topology support.
Is the CD74ACT240M pin-compatible with the CD74AC240M?
Yes, the CD74ACT240M and CD74AC240M share identical pinout, package (SOIC-20), and functional block diagram, but differ electrically: CD74ACT240M uses TTL-compatible input thresholds and operates only at 4.5–5.5V, while CD74AC240M supports 1.5–5.5V and CMOS thresholds. Substitution requires verifying supply voltage and input source compatibility - they are not drop-in replacements without system-level validation.
CD74ACT240M 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:
- 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:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
CD74ACT240M FAQ
1.How can I place an order for CD74ACT240M through Aetrix?
Please submit a Request for Quotation (RFQ) for CD74ACT240M 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 CD74ACT240M reliable?
The price and inventory of CD74ACT240M are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CD74ACT240M is usually 5 days.
3.What payment methods are accepted for CD74ACT240M?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CD74ACT240M transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CD74ACT240M?
CD74ACT240M orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CD74ACT240M 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 CD74ACT240M?
For technical support, including CD74ACT240M datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CD74ACT240M requirements.
6.How does Aetrix verify that CD74ACT240M is sourced from the original manufacturer or authorized distributors?
All CD74ACT240M 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 CD74ACT240M meets industry standards.
7.What is the process for return or replacement of CD74ACT240M?
All CD74ACT240M units undergo pre-shipment inspection (PSI). If there is an issue with CD74ACT240M, 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 CD74ACT240M part is unused and in its original packaging.
Return procedure for CD74ACT240M:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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