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onsemi MC74AC240NG
- Part No.:
- MC74AC240NG
- Manufacturer:
- onsemi
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
MC74AC240NG.pdf
- Description:
- IC BUFF INVERT 6V 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:4,602
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Product details
Overview
MC74AC240NG from onsemi is an octal non-inverting 3-state buffer/line driver used for memory address driving, clock distribution, and bidirectional bus interfacing in TTL- and CMOS-compatible systems. It operates from 2.0 V to 6.0 V, delivers ±24 mA output drive, features high-impedance outputs when enabled via dual independent OE controls (Pins 12/14/16/18 and Pins 3/5/7/9), and supports industrial temperature range (−40°C to +85°C).
For engineers reviewing the MC74AC240NG datasheet, pinout, applications, or equivalent options, this page provides verified functional identity, validated SOIC-20W package mapping, confirmed dual-OE 3-state control architecture, real-world bus-driving use cases, and two manufacturer-validated alternative parts with documented parameter and interface differences.
Technical Context
The MC74AC240NG implements eight independent non-inverting buffers, each with separate 3-state enable logic grouped into two banks (OE1 controlling Y1–Y4, OE2 controlling Y5–Y8). Its AC performance includes 4.5 ns typical propagation delay (tPLH/tPHL at VCC = 5.0 V, CL = 50 pF) and sub-9 ns max output enable/disable times, enabling reliable operation in high-speed address/data bus environments.
It uses standard CMOS input thresholds (VIH = 2.1 V min at VCC = 3.0 V; VIL = 0.9 V max), supports rail-to-rail output swing (VOH ≥ 2.9 V at VCC = 3.0 V; VOL ≤ 0.1 V), and maintains low dynamic power dissipation (CPD = 45 pF) - all while meeting JEDEC JESD78 latchup immunity (>±100 mA) and ESD robustness (>2000 V HBM).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 2.0 V to 6.0 V - enables direct interface with 3.3 V and 5 V logic domains without level shifters |
| Output Drive Strength | ±24 mA - sufficient to drive 50-pF loads at >20 MHz without signal degradation |
| Propagation Delay | 4.5 ns typical (VCC = 5.0 V, CL = 50 pF) - supports address/data bus timing in sub-10 ns critical paths |
| 3-State Enable/Disable Time | tPZH ≤ 7.0 ns, tPHZ ≤ 9.0 ns (VCC = 5.0 V) - minimizes bus contention during direction switching |
| Input Thresholds | VIH = 2.1 V min, VIL = 0.9 V max (VCC = 3.0 V) - ensures compatibility with both CMOS and TTL logic families |
| Quiescent Supply Current | ICC ≤ 80 µA - enables low-static-power operation in battery-backed or standby systems |
| ESD Rating | Human Body Model >2000 V - meets industrial I/O robustness requirements without external protection |
Pinout & Package
MC74AC240NG is supplied in a Pb-free SOIC-20 wide-body package (Case 751D), measuring 12.8 mm × 7.5 mm × 2.35 mm, with 1.27 mm pitch and gull-wing leads. It complies with JEDEC MS-013 and IPC-7351 standards.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 4, 6, 13, 15, 17, 19 | Inputs (A1–A4, A5–A8) | Eight buffered data inputs; non-inverting path to corresponding outputs |
| 3, 5, 7, 9 | OE2 Control Inputs | Active-low enable for outputs Y5–Y8; shared bank control for half of device |
| 12, 14, 16, 18 | OE1 Control Inputs | Active-low enable for outputs Y1–Y4; independent bank control for other half |
| 11, 10, 8, 19, 17, 15, 13, 2 | Outputs (Y1–Y8) | Eight 3-state outputs; high-impedance when respective OE is HIGH |
| 20 | VCC | Positive supply terminal; must be decoupled locally to minimize switching noise |
| 10 | GND | Ground reference for all inputs, outputs, and internal circuitry |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent 3-state enable banks | OE1 (Pins 12/14/16/18) and OE2 (Pins 3/5/7/9) allow selective activation of Y1–Y4 and Y5–Y8 groups - essential for split-bus or multi-master arbitration |
| High-output current drive | ±24 mA per output supports direct connection to 50 Ω transmission lines or multiple TTL loads without external drivers |
| Wide supply voltage range | 2.0 V to 6.0 V operation enables interoperability across legacy 5 V and modern 3.3 V subsystems in mixed-voltage designs |
| Low dynamic power consumption | 45 pF power dissipation capacitance limits switching current and reduces PCB-level EMI in dense routing environments |
| Pb-free and RoHS-compliant packaging | SOIC-20W (Case 751D) meets global environmental compliance mandates and reflow soldering profiles (JEDEC J-STD-020) |
Applications
| Memory Address Buffering | Clock Distribution |
|---|---|
Use Scenario: Driving 16-bit address bus from microcontroller to SRAM or Flash memory in embedded control systems. IC Role / Device Role / Timing Role: Non-inverting buffer with 3-state control isolates address lines during bus turnaround or idle cycles. Use Value: ±24 mA drive ensures full-swing signal integrity across 10 cm PCB traces at 20 MHz, eliminating need for additional line drivers. |
Use Scenario: Distributing system clock from oscillator to multiple peripherals (UART, SPI, timers) in industrial PLC modules. IC Role / Device Role / Timing Role: Low-skew, low-jitter buffer replicating clock signal with matched propagation delay across all eight outputs. Use Value: 4.5 ns typical tPLH/tPHL and <1 ns inter-output skew maintain setup/hold margins for synchronous peripherals. |
| Bus Transceiver Interface | Legacy System Expansion |
Use Scenario: Bidirectional data bus isolation between CPU and peripheral ASIC in retro-computing or test equipment backplanes. IC Role / Device Role / Timing Role: Dual-OE architecture enables directional control: OE1 active for read, OE2 active for write - preventing bus contention. Use Value: Independent OE banks eliminate external logic for direction control, reducing BOM count and layout complexity. |
Use Scenario: Interfacing modern microcontrollers with legacy 5 V parallel interfaces (e.g., dot-matrix displays, EPROM programmers). IC Role / Device Role / Timing Role: Level-shifting buffer translating 3.3 V GPIO outputs to 5 V-tolerant bus signals while maintaining fanout capability. Use Value: 2.0–6.0 V supply range and TTL-compatible VIH/VIL thresholds allow direct connection without discrete level translators. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal 3-state buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MC74ACT240DWR2G | TTL-compatible inputs (VIH = 2.0 V min at VCC = 4.5 V); identical SOIC-20W package and pinout | Better suited for mixed-logic systems where upstream drivers are standard TTL, not CMOS | Select when interfacing with 74LS or 74F series sources requiring lower VIH threshold |
| SN74AC240N | Same AC/DC specs and pinout; manufactured by Texas Instruments; slightly higher ICC (max 100 µA vs. 80 µA) | Valid drop-in replacement in TI-based designs; same thermal resistance (96 °C/W) | Choose for supply chain diversification where onsemi sourcing is constrained but identical functionality is required |
Compared with MC74AC240NG, MC74ACT240DWR2G offers tighter input compatibility with legacy TTL, while SN74AC240N provides second-source assurance with negligible electrical trade-offs - both retain identical 3-state timing, drive strength, and SOIC-20 footprint.
Availability
MC74AC240NG is available at Aetrix Electronics and suitable for memory address buffering, clock distribution, and bus transceiver applications requiring stable component supply, long-term industrial lifecycle support, and Pb-free compliance.
Supply support for MC74AC240NG 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
onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power management, analog, sensor, and logic solutions for automotive, industrial, and cloud infrastructure markets.
The MC74AC240NG belongs to onsemi's 74AC logic family - designed for high-speed, low-power, mixed-voltage digital interfacing in space-constrained industrial and computing systems.
FAQ
What is the maximum operating supply voltage for MC74AC240NG?
The MC74AC240NG supports a DC supply voltage range of −0.5 V to +6.5 V, with recommended operation from 2.0 V to 6.0 V. At VCC = 6.0 V, it maintains guaranteed VOH ≥ 5.4 V and VOL ≤ 0.44 V under 24 mA load, making MC74AC240NG suitable for 5 V legacy systems and margin-tolerant 6 V designs.
Does MC74AC240NG support true 3-state operation with independent control per output group?
Yes, MC74AC240NG provides two independent 3-state enable banks: OE1 (Pins 12/14/16/18) controls outputs Y1–Y4, and OE2 (Pins 3/5/7/9) controls Y5–Y8. This allows simultaneous or staggered bus access - for example, holding Y1–Y4 active while tri-stating Y5–Y8 during partial bus arbitration - a capability confirmed in the truth tables on page 1 of the datasheet.
What is the typical propagation delay of MC74AC240NG at 5 V supply?
The MC74AC240NG exhibits 4.5 ns typical propagation delay (tPLH and tPHL) at VCC = 5.0 V with CL = 50 pF, as specified in the AC Characteristics table on page 4. This value is measured from input transition (30% to 70% VCC) to output crossing 50% VCC, ensuring predictable timing in synchronous bus designs using MC74AC240NG.
Can MC74AC240NG be used in 3.3 V systems without level shifters?
Yes, MC74AC240NG is fully compatible with 3.3 V operation: its VIH minimum is 2.1 V at VCC = 3.0 V (scaling linearly), and VOH remains ≥2.9 V under −24 mA load. This allows direct connection to 3.3 V microcontrollers and FPGAs, confirming MC74AC240NG as a robust choice for mixed-voltage board design.
Is MC74AC240NG pin-compatible with MC74ACT240 devices?
Yes, MC74AC240NG and MC74ACT240 share identical SOIC-20W pinout, package dimensions, and functional block diagram. The only difference lies in input threshold specifications: MC74ACT240 has TTL-compatible VIH/VIL, while MC74AC240NG uses standard CMOS thresholds - both remain mechanically and electrically interchangeable in the same footprint.
MC74AC240NG Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74AC
- Package/Case:
- 20-DIP (0.300", 7.62mm)
- 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:
- 2V ~ 6V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 20-PDIP
MC74AC240NG FAQ
1.How can I place an order for MC74AC240NG through Aetrix?
Please submit a Request for Quotation (RFQ) for MC74AC240NG 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 MC74AC240NG reliable?
The price and inventory of MC74AC240NG are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC74AC240NG is usually 5 days.
3.What payment methods are accepted for MC74AC240NG?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC74AC240NG transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC74AC240NG?
MC74AC240NG orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC74AC240NG 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 MC74AC240NG?
For technical support, including MC74AC240NG datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC74AC240NG requirements.
6.How does Aetrix verify that MC74AC240NG is sourced from the original manufacturer or authorized distributors?
All MC74AC240NG 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 MC74AC240NG meets industry standards.
7.What is the process for return or replacement of MC74AC240NG?
All MC74AC240NG units undergo pre-shipment inspection (PSI). If there is an issue with MC74AC240NG, 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 MC74AC240NG part is unused and in its original packaging.
Return procedure for MC74AC240NG:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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