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onsemi MC74ACT245MG
- Part No.:
- MC74ACT245MG
- Manufacturer:
- onsemi
- Package:
- 20-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
MC74ACT245MG.pdf
- Description:
- IC TXRX NON-INVERT 5.5V 20SOEIAJ
- Quantity:
- Payment:
- Shipping:
Inventory:1,516
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Product details
Overview
MC74ACT245MG from onsemi is an octal bidirectional transceiver IC with 3-state inputs/outputs, designed for bus interface applications between TTL and CMOS systems. It features TTL-compatible inputs, ±24 mA output drive capability at both A and B ports, 5.0 V nominal supply operation, and propagation delay as low as 4.0 ns (tPLH/tPHL) under 5 V/50 pF conditions. It is used in microprocessor data bus isolation and level translation.
For engineers reviewing the MC74ACT245MG datasheet, pinout, applications, or equivalent options, key selection criteria include bidirectional bus control logic, 3-state enable timing (tPZH ≤ 10 ns), input voltage thresholds (VIH = 2.0 V min @ 5 V), and SOIC-20W Pb-free packaging compatibility with industrial temperature range (−40°C to +85°C).
Technical Context
The MC74ACT245MG implements eight non-inverting bidirectional buffers with independent 3-state control via OE and direction control via T/R. Its TTL-compatible inputs accept 2.0 V minimum VIH and 0.8 V maximum VIL at 5 V supply, enabling direct interfacing with legacy TTL logic without pull-ups. The device operates only within the 4.5 V to 5.5 V recommended VCC range and is not rated for 3.3 V operation.
Output switching is governed by synchronous enable/disable timing: tPZH/tPZL (enable) and tPHZ/tPLZ (disable) are all specified ≤12.0 ns max over temperature at 5 V/50 pF. Bus contention is prevented by guaranteed high-impedance isolation during OE HIGH, with IOZT ≤ ±6.0 µA at VCC = 5.5 V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.5 V to 5.5 V - Valid only for 5 V system interfaces; no 3.3 V operation supported |
| IOH/IOL | ±24 mA - Sustains full drive strength across −40°C to +85°C for robust bus loading |
| tPLH/tPHL | 4.0 ns typ / 8.0 ns max - Enables high-speed data transfer in 20–25 MHz bus cycles |
| VIH/VIL | 2.0 V min / 0.8 V max @ 5 V - Guarantees reliable recognition of TTL-level inputs |
| IOZT | ±6.0 µA max - Ensures minimal leakage in 3-state disabled mode for multi-driver buses |
| Propagation Skew | ≤1.0 ns - Maintains signal integrity across all 8 channels in parallel data paths |
Pinout & Package
MC74ACT245MG is housed in a 20-pin SOIC Wide Body (SOIC-20W, Case 751D) package, 7.5 mm wide, with 1.27 mm pitch and Pb-free finish (G suffix). Pin 1 is top-left corner, with GND at pin 10 and VCC at pin 20.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| OE (Pin 1) | Global 3-State Enable Input | Active-HIGH: disables both A and B ports into high-Z; required for bus arbitration |
| T/R (Pin 2) | Data Direction Control | Active-HIGH = A→B; Active-LOW = B→A; synchronizes with OE for glitch-free direction switching |
| A0–A7 (Pins 3–10) | Side A I/O Terminals | Bidirectional ports with 24 mA sink/source; share same electrical characteristics as B-side |
| GND (Pin 10) | Ground Reference | Common return for all I/O and supply currents; pin 10 is shared ground node |
| B0–B7 (Pins 11–18) | Side B I/O Terminals | Electrically identical to A-side; supports symmetrical bus loading in either direction |
| VCC (Pin 20) | Power Supply | 5 V only; decoupling capacitor required adjacent to pin 20 for noise immunity |
Key Features
| Feature | Design Value |
|---|---|
| TTL-Compatible Inputs | VIH = 2.0 V min and VIL = 0.8 V max at 5 V allow direct connection to 74LS/74F families without level shifters |
| Matched Bidirectional Drive | Identical ±24 mA sourcing/sinking on both A and B ports ensures balanced signal integrity in either direction |
| Fast 3-State Control | tPZH/tPHZ ≤ 10 ns enables rapid bus turnaround in time-critical multiplexed architectures |
| Pb-Free SOIC-20W Package | RoHS-compliant 751D case with moisture sensitivity level 1 supports standard reflow without baking |
Applications
| Microprocessor Data Bus Isolation | Legacy System Level Translation |
|---|---|
Use Scenario: Isolating CPU address/data bus from peripheral expansion slots to prevent loading and contention. IC Role / Device Role / Timing Role: Bidirectional transceiver enabling controlled data flow between master and slave devices on shared bus segments. Use Value: ±24 mA drive sustains signal integrity across 10+ loads; 3-state timing prevents bus glitches during direction changes. | Use Scenario: Interfacing 5 V TTL peripherals (e.g., UARTs, PIOs) with modern 5 V CMOS controllers. IC Role / Device Role / Timing Role: Voltage- and logic-family translator with direction control synchronized to system handshake signals. Use Value: TTL-compatible inputs eliminate external pull-ups; matched A/B drive avoids skew in mixed-technology backplanes. |
| Industrial PLC Backplane Interface | Test Equipment Signal Routing |
Use Scenario: Managing bidirectional data exchange between CPU module and I/O carrier boards in modular PLC chassis. IC Role / Device Role / Timing Role: Bus buffer with OE-gated 3-state and T/R-controlled direction for hot-swap-safe backplane communication. Use Value: IOZT ≤ ±6.0 µA ensures negligible leakage during module insertion/removal; industrial temp rating supports harsh environments. | Use Scenario: Reconfigurable signal path routing in automated test equipment (ATE) where DUT interfaces vary per test sequence. IC Role / Device Role / Timing Role: Programmable bus switch enabling dynamic assignment of stimulus/response channels under controller command. Use Value: Sub-10 ns enable/disable timing allows real-time path reconfiguration within single clock cycles of test sequencer. |
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 | Different manufacturer (TI); identical 5 V VCC range, ±24 mA drive, and SOIC-20 package but uses legacy marking and non-Pb-free plating unless specified. | Same functional role in bus isolation; requires verification of Pb-free compliance and moisture sensitivity level for new production. | Select SN74ACT245N only if legacy TI qualification or specific TI ecosystem alignment is required. |
| 74ACT245SCX | ON Semiconductor alternate marking; same die and specs as MC74ACT245MG but offered in TSSOP-20 (DT suffix) instead of SOIC-20W. | Used where board space is constrained; TSSOP footprint reduces area by ~45% but requires tighter assembly process control. | Choose 74ACT245SCX when PCB real estate is limited and reflow profile supports fine-pitch TSSOP handling. |
Compared with SN74ACT245N and 74ACT245SCX, the MC74ACT245MG provides guaranteed Pb-free SOIC-20W packaging with MSL-1 rating and documented industrial temperature performance, making it preferred for new designs requiring RoHS compliance and simplified manufacturing.
Availability
MC74ACT245MG is available at Aetrix Electronics and suitable for microprocessor bus isolation, industrial PLC backplane interfaces, and legacy system level translation requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for MC74ACT245MG 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, analog, sensor, and connectivity solutions for automotive, industrial, cloud, medical, and IoT applications.
The MC74ACT245MG belongs to onsemi's 74ACT logic family, engineered for high-speed, low-power 5 V bus interface applications with strict TTL compatibility and industrial-grade reliability.
FAQ
What is the recommended operating voltage range for the MC74ACT245MG?
The MC74ACT245MG is specified for 4.5 V to 5.5 V DC supply only. Operation outside this range - including at 3.3 V - is not supported and may result in undefined logic behavior or parametric failure. The device's TTL-compatible inputs and output drive characteristics are validated exclusively within this 5 V domain, as confirmed in the Recommended Operating Conditions table on page 2 of the official datasheet.
Does the MC74ACT245MG support bidirectional data flow without external logic?
Yes, the MC74ACT245MG supports fully autonomous bidirectional data flow using its dedicated T/R (Transmit/Receive) input. When T/R is HIGH, data passes from A ports to B ports; when LOW, data flows from B to A. This direction control operates independently of OE, and both signals are CMOS-compatible, eliminating need for external inverters or glue logic in standard bus configurations.
What is the maximum capacitive load the MC74ACT245MG can drive reliably?
The MC74ACT245MG is characterized for reliable operation with up to 50 pF total load capacitance per output, as used in all AC timing specifications (e.g., tPLH, tPHL). Driving higher capacitance may increase propagation delay and reduce noise margin; for loads exceeding 50 pF, designers should verify signal integrity via simulation or bench testing using the device's 15 pF typical CI/O and 45 pF CPD values.
Is the MC74ACT245MG pin-compatible with the MC74AC245MG?
No, the MC74ACT245MG is not pin-compatible with the MC74AC245MG in functional operation despite identical pinout. While both share the same SOIC-20W package and terminal mapping, the MC74AC245MG has CMOS-input thresholds (VIH = 3.15 V min @ 5 V), whereas the MC74ACT245MG uses TTL-compatible inputs (VIH = 2.0 V min). Swapping them may cause logic misreads in TTL-driven systems.
What thermal considerations apply to the MC74ACT245MG in continuous operation?
The MC74ACT245MG has a junction-to-air thermal resistance (θJA) of 96°C/W in SOIC-20W package. At maximum ICC (80 µA) and full 24 mA output loading on all 8 channels, power dissipation remains below 100 mW - well within safe limits for standard PCB layouts without heatsinking. However, sustained simultaneous sourcing/sinking across multiple outputs warrants verification of local board temperature rise, especially in enclosed industrial enclosures above 70°C ambient.
MC74ACT245MG Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74ACT
- Package/Case:
- 20-SOIC (0.209", 5.30mm Width)
- 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:
- Surface Mount
- Supplier Device Package:
- SOEIAJ-20
MC74ACT245MG FAQ
1.How can I place an order for MC74ACT245MG through Aetrix?
Please submit a Request for Quotation (RFQ) for MC74ACT245MG 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 MC74ACT245MG reliable?
The price and inventory of MC74ACT245MG are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC74ACT245MG is usually 5 days.
3.What payment methods are accepted for MC74ACT245MG?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC74ACT245MG transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC74ACT245MG?
MC74ACT245MG orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC74ACT245MG 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 MC74ACT245MG?
For technical support, including MC74ACT245MG datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC74ACT245MG requirements.
6.How does Aetrix verify that MC74ACT245MG is sourced from the original manufacturer or authorized distributors?
All MC74ACT245MG 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 MC74ACT245MG meets industry standards.
7.What is the process for return or replacement of MC74ACT245MG?
All MC74ACT245MG units undergo pre-shipment inspection (PSI). If there is an issue with MC74ACT245MG, 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 MC74ACT245MG part is unused and in its original packaging.
Return procedure for MC74ACT245MG:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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