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onsemi MC74ACT245NG
- Part No.:
- MC74ACT245NG
- Manufacturer:
- onsemi
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
MC74ACT245NG.pdf
- Description:
- IC TXRX NON-INVERT 5.5V 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:4,905
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Product details
Overview
MC74ACT245NG from onsemi is an octal bidirectional transceiver with 3-state inputs/outputs, designed for bus-oriented data transfer between two 8-bit buses. It features TTL-compatible inputs, ±24 mA output drive capability at both A and B ports, and operates over 4.5 V to 5.5 V supply. It is used in microcontroller system buses, memory expansion interfaces, and legacy parallel I/O bridging.
For engineers reviewing the MC74ACT245NG datasheet, pinout, applications, or equivalent options, key selection criteria include direction control (T/R), 3-state enable (OE), bidirectional current drive, AC timing at 5 V, and SOIC-20W Pb-free packaging compatibility with industrial temperature range.
Technical Context
The MC74ACT245NG implements eight non-inverting bidirectional buffers with independent 3-state control via OE and directional control via T/R. Its TTL-compatible inputs accept standard 5 V logic thresholds (VIH = 2.0 V min, VIL = 0.8 V max at VCC = 5.5 V), enabling direct interfacing with legacy microcontrollers and peripherals.
Propagation delay is specified at 1.5–8.0 ns (tPLH/tPHL) and output enable/disable times range from 1.5–11.0 ns (tPZH/tPLZ/tPHZ/tPLZ) under 5.0 V ±0.5 V and CL = 50 pF conditions - optimized for high-speed bus arbitration in real-time embedded systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - ensures compatibility with 5 V TTL and CMOS logic families without level shifting. |
| Output Drive | ±24 mA per pin - supports driving multiple loads or longer traces on shared data buses. |
| Propagation Delay | 1.5–8.0 ns - enables sub-10 ns bus turnaround for high-throughput parallel transfers. |
| Input Thresholds | VIH = 2.0 V min, VIL = 0.8 V max at 5.5 V - guarantees robust noise margin against TTL-level signals. |
| 3-State Leakage | ±6.0 µA max - minimizes bus contention current when outputs are disabled. |
| Operating Temp | −40 °C to +85 °C - qualified for industrial and automotive under-hood control modules. |
| Package | SOIC-20 Wide Body (Case 751D) - surface-mount compatible with standard reflow profiles and IPC-7351B land patterns. |
Pinout & Package
MC74ACT245NG is housed in a 20-pin SOIC-Wide (Case 751D) package with 0.300-inch body width, 1.27 mm pitch, and Pb-free finish (G suffix). Pin 1 is located at the top-left corner with notch or index mark orientation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (OE) | Output Enable Input | Active-HIGH control: drives all A/B pins into high-impedance state when HIGH. |
| 2 (T/R) | Transmit/Receive Input | Active-HIGH = A→B data flow; Active-LOW = B→A data flow - determines bus direction dynamically. |
| 3–10 (A0–A7) | Side A I/O Terminals | Bidirectional 3-state pins - connect to local bus (e.g., MCU data bus); function as input or output based on T/R state. |
| 11 (GND) | Ground Reference | Primary signal return path - must be low-inductance connection to minimize ground bounce during switching. |
| 12–19 (B0–B7) | Side B I/O Terminals | Bidirectional 3-state pins - connect to remote bus (e.g., peripheral or memory bus); mirror A-side behavior. |
| 20 (VCC) | Power Supply | +5 V DC supply - requires local 0.1 µF ceramic decoupling capacitor placed within 5 mm of pin. |
Key Features
| Feature | Design Value |
|---|---|
| TTL-Compatible Inputs | Accepts standard 5 V TTL logic levels without external biasing - simplifies integration with legacy 8051, Z80, or 68K-based systems. |
| Bidirectional Bus Control | Single T/R pin configures full-duplex data flow direction - eliminates need for separate transmit/receive transceivers or multiplexers. |
| High Sink/Source Current | 24 mA per I/O supports fan-out to ≥10 LS-TTL loads or direct LED driving - reduces need for external buffers in I/O expansion designs. |
| Pb-Free SOIC-20W Package | RoHS-compliant wide-body SOIC meets IPC/JEDEC J-STD-020 moisture sensitivity Level 1 - suitable for lead-free reflow assembly without baking. |
Applications
| Microcontroller System Bus Expansion | Legacy Parallel Peripheral Interface |
|---|---|
Use Scenario: Expanding GPIO or data bus width of an 8-bit MCU (e.g., ATmega128, PIC18F) to interface with external SRAM or EPROM. IC Role / Device Role / Timing Role: Bidirectional data bridge between MCU D0–D7 and memory D0–D7, controlled by address decode and RD/WR strobes. Use Value: Enables zero-wait-state memory access with <8 ns propagation delay and 24 mA drive - maintains timing integrity across PCB traces up to 10 cm. | Use Scenario: Connecting an industrial PLC CPU module to parallel I/O expansion cards using standardized 20-pin ribbon cable. IC Role / Device Role / Timing Role: Isolates and buffers bidirectional data lines between master and slave modules while supporting hot-swap-safe 3-state disable. Use Value: ±24 mA drive sustains signal integrity over 30 cm cables; OE-controlled high-Z prevents bus contention during card insertion/removal. |
| Industrial Sensor Data Aggregation | Automotive Diagnostic Interface Adapter |
Use Scenario: Aggregating parallel outputs from eight analog-to-digital converters (ADCs) onto a shared microcontroller data bus. IC Role / Device Role / Timing Role: Synchronizes sampling data from multiple ADCs into a single 8-bit bus using T/R and OE coordinated with sample clock edge. Use Value: Sub-10 ns propagation delay ensures time-aligned capture across channels; 3-state isolation prevents crosstalk between ADC sampling phases. | Use Scenario: Adapting proprietary 8-bit diagnostic bus (e.g., GM Class 2 or Ford SCP) to modern CAN-based gateway controllers. IC Role / Device Role / Timing Role: Translates parallel status/data bits from legacy ECU test port to microcontroller's parallel input port for protocol conversion firmware. Use Value: TTL-compatible inputs directly accept 0–5 V diagnostic signals; −40 °C to +85 °C rating matches under-dash automotive environment requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bidirectional bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ACT245N | Same logic function, identical AC/DC specs, but TI-marked SOIC-20 package with different marking layout and MSL Level 1 compliance. | No functional difference; validated for same 5 V bus buffering roles including microcontroller expansion and sensor aggregation. | Select SN74ACT245N if sourcing from TI-authorized channels or requiring TI-specific qualification documentation. |
| 74ACT245PC | Identical electrical specs and pinout, but packaged in PDIP-20 (through-hole) instead of SOIC-20W - larger footprint and no Pb-free guarantee unless explicitly marked. | Suitable only for prototyping or legacy through-hole PCBs; not recommended for new surface-mount industrial designs. | Choose 74ACT245PC only for hand-soldered evaluation or repair of existing DIP-based systems. |
Compared with MC74ACT245NG, SN74ACT245N offers identical performance in a functionally interchangeable SOIC-20 package, while 74ACT245PC provides pin-equivalent functionality in through-hole form - making the former a true alternative for volume SMT production and the latter limited to legacy board repair.
Availability
MC74ACT245NG is available at Aetrix Electronics and suitable for microcontroller bus expansion, industrial I/O interfacing, and automotive diagnostic adapter designs requiring stable component supply, RoHS compliance, and industrial temperature operation.
Supply support for MC74ACT245NG 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 focused on energy-efficient power, analog, sensing, and connectivity solutions for automotive, industrial, cloud, medical, and IoT applications.
The MC74ACT245NG belongs to onsemi's legacy 74ACT logic family - engineered for high-speed, low-power 5 V TTL-compatible bus interfacing in industrial control and embedded systems where reliability and long-term availability are critical.
FAQ
What is the maximum operating voltage for MC74ACT245NG?
The MC74ACT245NG has a maximum rated supply voltage of 5.5 V DC. Operation above this level risks permanent damage per Absolute Maximum Ratings. The device is specified for reliable operation only within 4.5 V to 5.5 V, with typical performance characterized at 5.0 V ±0.5 V. Exceeding 5.5 V violates the VCC limit and may cause latch-up or parametric shift in MC74ACT245NG.
Does MC74ACT245NG support hot-swapping on a live bus?
MC74ACT245NG supports controlled hot-swap operation only when OE is held HIGH before insertion, placing all I/O pins in high-impedance state. Its ±6.0 µA 3-state leakage and bus-hold immunity are not guaranteed; external series resistors or dedicated hot-swap controllers are recommended. MC74ACT245NG does not include built-in hot-swap protection circuitry.
Can MC74ACT245NG operate at 3.3 V supply?
No, MC74ACT245NG is not rated for 3.3 V operation. Its recommended VCC range is strictly 4.5 V to 5.5 V. At 3.3 V, input thresholds (VIH/VIL) and output drive (VOH/VOL) fall outside specification, and propagation delay increases unpredictably. Use MC74AC245NG or 74LVC245 for 3.3 V systems - MC74ACT245NG requires 5 V nominal supply.
What is the thermal resistance (θJA) of MC74ACT245NG in SOIC-20W package?
The junction-to-ambient thermal resistance (θJA) for MC74ACT245NG in SOIC-20W (Case 751D) package is 96 °C/W, measured per JESD51-7 on a standard 4-layer JEDEC test board. This value assumes proper PCB copper pour and thermal vias under the package. Derating is required above 85 °C ambient; MC74ACT245NG maximum junction temperature is 140 °C.
Is MC74ACT245NG pin-compatible with MC74AC245NG?
Yes, MC74ACT245NG and MC74AC245NG share identical pinout, package (SOIC-20W), and logic function. The key difference is input threshold compatibility: MC74ACT245NG has TTL-compatible inputs (VIH = 2.0 V min), while MC74AC245NG uses CMOS thresholds (VIH = 3.15 V min at 4.5 V). Both devices can substitute in same PCB layout, but signal source logic family must match MC74ACT245NG's TTL input requirement.
MC74ACT245NG Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74ACT
- Package/Case:
- 20-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- 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:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 20-PDIP
MC74ACT245NG FAQ
1.How can I place an order for MC74ACT245NG through Aetrix?
Please submit a Request for Quotation (RFQ) for MC74ACT245NG 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 MC74ACT245NG reliable?
The price and inventory of MC74ACT245NG are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC74ACT245NG is usually 5 days.
3.What payment methods are accepted for MC74ACT245NG?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC74ACT245NG transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC74ACT245NG?
MC74ACT245NG orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC74ACT245NG 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 MC74ACT245NG?
For technical support, including MC74ACT245NG datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC74ACT245NG requirements.
6.How does Aetrix verify that MC74ACT245NG is sourced from the original manufacturer or authorized distributors?
All MC74ACT245NG 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 MC74ACT245NG meets industry standards.
7.What is the process for return or replacement of MC74ACT245NG?
All MC74ACT245NG units undergo pre-shipment inspection (PSI). If there is an issue with MC74ACT245NG, 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 MC74ACT245NG part is unused and in its original packaging.
Return procedure for MC74ACT245NG:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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