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onsemi MC74ACT640DWG
- Part No.:
- MC74ACT640DWG
- Manufacturer:
- onsemi
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
MC74ACT640DWG.pdf
- Description:
- IC TXRX INVERT 5.5V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,358
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Product details
Overview
MC74ACT640DWG from onsemi is an octal 3-state inverting bus transceiver designed for asynchronous bidirectional data exchange between two 8-bit buses. It supports A→B or B→A direction control via the T/R pin, features ±24 mA output drive, TTL-compatible inputs, and operates at 4.5–5.5 V supply. It is used in industrial backplane interfaces requiring isolated bus communication.
For engineers reviewing the MC74ACT640DWG datasheet, pinout, applications, or equivalent options, key selection criteria include bidirectional 3-state timing (tPLH/tPHL ≤ 8.5 ns), OE/T/R control logic compatibility, ±24 mA drive capability, SOIC-20W package thermal resistance (96 °C/W), and Pb-free compliance per JEDEC Level 1 MSL.
Technical Context
The MC74ACT640DWG implements a dual-bus transceiver architecture with independent 3-state control: OE enables/disables all outputs, while T/R selects direction (A→B when HIGH, B→A when LOW). Its TTL-compatible inputs accept 0.8 V/2.0 V thresholds, and outputs meet VOH ≥ 4.4 V / VOL ≤ 0.1 V at ±24 mA under 4.5–5.5 V operation.
Propagation delays are specified at CL = 50 pF and VCC = 5.0 V ±0.5 V, with tPLH/tPHL ≤ 8.5/9.0 ns over −40°C to +85°C. Output disable times (tPLZ/tPHZ) and enable times (tPZL/tPZH) are ≤11.0 ns, ensuring tight timing control in synchronous bus systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.5 V to 5.5 V - Ensures compatibility with standard 5 V TTL and CMOS logic rails. |
| Output Drive | ±24 mA - Supports direct interface to multiple TTL loads without external buffering. |
| Propagation Delay | tPLH/tPHL ≤ 8.5/9.0 ns - Enables reliable operation in high-speed bus systems up to ~100 MHz effective throughput. |
| Input Thresholds | VIH = 2.0 V, VIL = 0.8 V - Guarantees robust noise margin against TTL-level signals. |
| 3-State Leakage | IOZ ≤ ±5.0 µA - Minimizes bus contention current during isolation mode. |
| Thermal Resistance | JA = 96 °C/W - Defines junction-to-ambient rise under full-load conditions in SOIC-20WB package. |
| ESD Rating | HBM > 2000 V - Provides baseline handling robustness in manufacturing and assembly environments. |
Pinout & Package
MC74ACT640DWG is housed in a 20-lead SOIC Wide Body (SOIC-20W, Case 751D) package measuring 12.8 mm × 7.5 mm × 2.5 mm (max height), with 1.27 mm pitch, Pb-free finish, and JEDEC Level 1 moisture sensitivity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A7 | Side A bidirectional I/O | Configurable as input (when opposite side drives) or 3-state output (when enabled and direction matches). |
| B0–B7 | Side B bidirectional I/O | Same behavior as A0–A7; forms mirrored 8-bit bus port. |
| OE | Active-low output enable | Drives all A/B outputs into high-impedance state when HIGH; required for bus isolation. |
| T/R | Direction control | HIGH = A→B transmission; LOW = B→A transmission - defines data flow path unambiguously. |
| VCC | Positive supply | Connects to 4.5–5.5 V rail; decoupling capacitor (0.1 µF) recommended near pin 20. |
| GND | Ground reference | Common return for all signals and supply; must be low-impedance connection to minimize noise coupling. |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional 3-state control | Independent OE and T/R inputs allow precise bus arbitration and direction switching without glitches. |
| ±24 mA output sink/source | Meets TTL fan-out requirements (up to 10 LSTTL loads) without external drivers. |
| TTL-compatible input thresholds | VIH = 2.0 V / VIL = 0.8 V ensures interoperability with legacy 5 V logic families. |
| Pb-free SOIC-20W package | Complies with RoHS Directive 2011/65/EU and JEDEC MSL Level 1 for unlimited floor life. |
| Low propagation skew | tPLH/tPHL variation ≤ 0.5 ns across all 8 channels - critical for parallel bus timing integrity. |
Applications
| Industrial Backplane Interface | Legacy System Bus Extension |
|---|---|
Use Scenario: Isolating and extending 8-bit data paths between CPU and peripheral modules in programmable logic controllers. IC Role / Device Role / Timing Role: Bidirectional bus buffer with direction-selectable 3-state outputs synchronized to system clock edges. Use Value: Enables hot-swap-capable module insertion by isolating inactive buses via OE control, reducing signal integrity risk. | Use Scenario: Interfacing vintage microprocessor development boards (e.g., Z80, 8085) with modern FPGA-based peripherals. IC Role / Device Role / Timing Role: Voltage- and timing-transparent bus translator supporting TTL-level signaling and sub-10 ns propagation. Use Value: Eliminates need for discrete level-shifting or latch logic, preserving original bus timing budgets. |
| Test Equipment Data Routing | Automated Test Fixture Control |
Use Scenario: Dynamically reconfiguring signal paths in automated test equipment (ATE) to route DUT I/O through calibration or stimulus channels. IC Role / Device Role / Timing Role: Reversible bus switch controlled by FPGA GPIO, enabling real-time path reassignment. Use Value: Reduces fixture complexity by replacing mechanical relays with solid-state, wear-free routing. | Use Scenario: Controlling multiple sensor readout lines in production-line functional testers where bus contention must be avoided during parallel sampling. IC Role / Device Role / Timing Role: Isolation gate that prevents back-driving of shared analog/digital lines during multiplexed acquisition. Use Value: Prevents measurement corruption caused by simultaneous driver activation across test channels. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal bidirectional bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ACT640N | Dual-in-line (PDIP-20) package; identical AC/DC specs but higher thermal resistance (105 °C/W). | Suitable for prototyping or through-hole PCBs; not recommended for high-density or thermally constrained layouts. | Select when hand-soldering or breadboard validation is required; avoid for volume surface-mount production. |
| 74LCX640M | Lower VCC range (2.0–3.6 V); 3.3 V only; ±24 mA drive retained but VOH/VOL optimized for LVTTL. | Designed for mixed-voltage 3.3 V/5 V systems; requires level translation if interfacing with pure 5 V buses. | Choose for 3.3 V core logic domains; not drop-in compatible with MC74ACT640DWG due to voltage incompatibility. |
Compared with SN74ACT640N and 74LCX640M, the MC74ACT640DWG provides optimal thermal performance in SOIC-20W for 5 V industrial bus applications, while avoiding the voltage domain mismatch of the 3.3 V-only 74LCX640M and the layout limitations of PDIP packaging.
Availability
MC74ACT640DWG is available at Aetrix Electronics and suitable for industrial backplane interfaces, legacy system bus extensions, test equipment data routing, and automated test fixture control requiring stable component supply and long-term lifecycle support.
Supply support for MC74ACT640DWG 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 delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.
The MC74ACT640DWG belongs to onsemi's advanced logic family targeting high-reliability 5 V digital interconnects, specifically engineered for noise-immune, low-skew bidirectional bus communication in harsh industrial environments.
FAQ
What is the maximum operating temperature range for the MC74ACT640DWG?
The MC74ACT640DWG is rated for continuous operation from −40°C to +85°C ambient temperature, as specified in the Recommended Operating Conditions table. This range applies to all package types including the SOIC-20W variant. Junction temperature must remain below 140°C under bias, and thermal design must account for JA = 96 °C/W to ensure reliability within this envelope. The MC74ACT640DWG maintains full DC and AC specifications across this full industrial temperature span.
Does the MC74ACT640DWG support true bidirectional data flow without external logic?
Yes, the MC74ACT640DWG supports true bidirectional data flow using only its dedicated T/R (Transmit/Receive) input: when T/R = HIGH, data flows from A-side to B-side; when T/R = LOW, data flows from B-side to A-side. No external latches or direction-control logic are needed. The MC74ACT640DWG integrates this functionality directly, with propagation delays symmetrically specified for both directions (tPLH/tPHL ≤ 8.5/9.0 ns).
What is the purpose of the OE (Output Enable) pin on the MC74ACT640DWG?
The OE pin on the MC74ACT640DWG is an active-low control that places all A0–A7 and B0–B7 outputs into high-impedance (3-state) mode when asserted HIGH, effectively isolating both buses regardless of T/R state. This enables safe bus sharing in multi-master systems. When OE = LOW, the device operates normally per T/R setting. The MC74ACT640DWG specifies IOZ ≤ ±5.0 µA in 3-state mode, ensuring minimal leakage-induced contention.
Is the MC74ACT640DWG pin-compatible with other octal transceivers like the 74ACT245?
No, the MC74ACT640DWG is not pin-compatible with the 74ACT245. While both are octal transceivers, the MC74ACT640DWG uses a dual-bus bidirectional architecture with separate A/B I/O banks and dedicated T/R/OE controls in a 20-pin SOIC, whereas the 74ACT245 uses a unidirectional A→B architecture with DIR/EN controls in a 20-pin SOIC but with different pin assignments (e.g., no B-side inputs). Pin mapping, truth table, and functional behavior differ fundamentally - the MC74ACT640DWG requires distinct PCB layout.
What does the "G" suffix in MC74ACT640DWG indicate?
The "G" suffix in MC74ACT640DWG denotes a Pb-free (lead-free) package compliant with RoHS Directive 2011/65/EU. It confirms that the SOIC-20W body, leads, and finish contain no intentionally added lead, and that the device meets JEDEC Moisture Sensitivity Level 1 (unlimited floor life). This marking aligns with onsemi's standardized Pb-free indicator per the datasheet's ordering information section - the MC74ACT640DWG is fully RoHS-compliant and suitable for lead-free reflow soldering processes.
MC74ACT640DWG Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74ACT
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Logic Type:
- Transceiver, 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:
- 20-SOIC
MC74ACT640DWG FAQ
1.How can I place an order for MC74ACT640DWG through Aetrix?
Please submit a Request for Quotation (RFQ) for MC74ACT640DWG 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 MC74ACT640DWG reliable?
The price and inventory of MC74ACT640DWG are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC74ACT640DWG is usually 5 days.
3.What payment methods are accepted for MC74ACT640DWG?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC74ACT640DWG transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC74ACT640DWG?
MC74ACT640DWG orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC74ACT640DWG 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 MC74ACT640DWG?
For technical support, including MC74ACT640DWG datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC74ACT640DWG requirements.
6.How does Aetrix verify that MC74ACT640DWG is sourced from the original manufacturer or authorized distributors?
All MC74ACT640DWG 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 MC74ACT640DWG meets industry standards.
7.What is the process for return or replacement of MC74ACT640DWG?
All MC74ACT640DWG units undergo pre-shipment inspection (PSI). If there is an issue with MC74ACT640DWG, 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 MC74ACT640DWG part is unused and in its original packaging.
Return procedure for MC74ACT640DWG:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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