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onsemi MC74ACT640DW
- Part No.:
- MC74ACT640DW
- Manufacturer:
- onsemi
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
MC74ACT640DW.pdf
- Description:
- IC TXRX INVERT 5.5V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,848
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Product details
Overview
MC74ACT640DW 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 T/R input, features ±24 mA output drive, TTL-compatible inputs, and operates over −40°C to +85°C at 4.5–5.5 V supply - used in industrial backplane interface and legacy system bus bridging.
For engineers reviewing the MC74ACT640DW datasheet, pinout, applications, or equivalent options, key selection criteria include bidirectional 3-state control timing (tPLH/tPHL ≤ 8.5 ns), OE/T/R logic coordination, SOIC-20W package thermal resistance (96 °C/W), and Pb-free compliance per JEDEC Level 1 MSL.
Technical Context
The MC74ACT640DW implements dual-bus isolation using independent 3-state outputs on both A and B sides, with direction determined by the T/R input and output enable controlled by OE. Its TTL-compatible inputs accept 0.8 V (VIL) and 2.0 V (VIH) thresholds, while outputs deliver VOH ≥ 4.4 V and VOL ≤ 0.1 V under −24 mA/24 mA load at VCC = 4.5 V.
Propagation delays are specified at CL = 50 pF and VCC = 5.0 V ±0.5 V: tPLH/tPHL ≤ 8.5/9.0 ns across temperature, and output enable/disable times (tPZH/tPLZ/tPHZ/tPLZ) ≤ 11.0 ns. The device exhibits latch-up immunity of ±100 mA per I/O at 85°C and ESD robustness >2000 V HBM.
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 systems without level-shifting. |
| Output Drive | ±24 mA - sufficient to drive multiple TTL loads or terminate stubs in medium-speed bus topologies. |
| Propagation Delay | ≤ 8.5 ns (tPLH), ≤ 9.0 ns (tPHL) - enables reliable operation up to ~100 MHz bus toggle rates in point-to-point configurations. |
| 3-State Leakage | ±5.0 µA (IOZ) - minimizes bus contention current when outputs are disabled, critical for hot-swap or shared-bus arbitration. |
| ESD Rating | >2000 V HBM - meets industrial handling requirements without additional board-level protection circuitry. |
| Thermal Resistance | 96 °C/W (JA) - defines maximum power dissipation limit (~150 mW at ΔT = 14.4°C rise) in SOIC-20W package. |
Pinout & Package
MC74ACT640DW is housed in a 20-pin SOIC Wide Body (SOIC-20W, Case 751D) package with 1.27 mm pitch, 12.8 mm × 7.5 mm body size, and 2.5 mm height. Pin 1 is marked with a notch or dot; pin numbering follows standard counter-clockwise orientation from top view.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A7 | Side A bidirectional I/O terminals | Function as inputs when data flows B→A; become high-impedance outputs when OE = HIGH or direction mismatched. |
| B0–B7 | Side B bidirectional I/O terminals | Function as inputs when data flows A→B; enter 3-state when OE = HIGH or direction inactive. |
| OE | Active-low output enable | When LOW, enables transceiver function; when HIGH, forces all A/B pins into high-impedance state regardless of T/R. |
| T/R | Transmit/Receive direction control | HIGH selects A→B path; LOW selects B→A path - must be stable before OE activation to avoid bus glitches. |
| VCC | Positive supply | Connected to 4.5–5.5 V rail; decoupling capacitor (0.1 µF) required within 5 mm of pin 20 for noise suppression. |
| GND | Ground reference | Connected to system ground plane; shares return path with all I/Os - layout must minimize impedance to reduce ground bounce. |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional bus isolation | Independent 3-state control per side allows dynamic reconfiguration of data flow without external multiplexers. |
| ±24 mA output sink/source | Supports direct connection to 10+ TTL inputs or termination resistors in parallel bus architectures. |
| TTL-compatible input thresholds | VIL ≤ 0.8 V and VIH ≥ 2.0 V ensure interoperability with legacy 5 V logic families without level translation. |
| Pb-free SOIC-20W package | Meets RoHS Directive 2011/65/EU and JEDEC MSL Level 1 - suitable for standard reflow soldering processes. |
Applications
| Industrial Backplane Interface | Legacy System Bus Bridging |
|---|---|
Use Scenario: Interfacing microcontroller local bus to ISA or VME-style expansion backplanes with separate address/data lanes. IC Role / Device Role / Timing Role: Bidirectional data path controller that isolates master and slave domains during bus arbitration cycles. Use Value: Enables synchronous handshaking between mismatched clock domains using OE/T/R coordination, reducing inter-board skew. |
Use Scenario: Connecting 80C188-based control modules to older 8-bit peripheral cards requiring 5 V tolerant I/O. IC Role / Device Role / Timing Role: Voltage- and logic-level transparent bridge that preserves setup/hold timing margins across bus segments. Use Value: Eliminates need for discrete buffer arrays while maintaining <8.5 ns propagation delay for cycle-accurate transfers. |
| Test Equipment Data Routing | Programmable Logic Interface |
Use Scenario: Dynamic signal routing in automated test equipment where DUT I/O lines must be switched between stimulus and measurement paths. IC Role / Device Role / Timing Role: Reconfigurable 8-bit channel selector controlled by FPGA GPIOs driving OE and T/R. Use Value: Provides glitch-free switching with <11 ns enable/disable latency, enabling sub-microsecond test vector transitions. |
Use Scenario: Interfacing CPLD configuration data streams to external PROMs or flash memory in boundary-scan JTAG chains. IC Role / Device Role / Timing Role: Isolating programming voltage domain from core logic during ISP operations. Use Value: Prevents back-drive damage during hot-configuration via 3-state disable (OE = HIGH) while preserving pin compatibility. |
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 | PDIP-20 package; higher thermal resistance (105 °C/W); identical AC/DC specs and pinout. | Suitable for prototyping or through-hole assembly; not recommended for high-density PCBs or automated SMT lines. | Select SN74ACT640N only when manual soldering or socket-based validation is required. |
| 74LCX640M | Lower VCC range (2.0–3.6 V); 3.3 V logic family; 24 mA drive reduced to ±24 mA at 3.3 V but lower VOH/VOL swing. | Designed for mixed-voltage systems with 3.3 V core logic; incompatible with 5 V-only buses without level shifters. | Choose 74LCX640M only when migrating to 3.3 V infrastructure and verifying bus termination compatibility. |
Compared with SN74ACT640N and 74LCX640M, the MC74ACT640DW offers optimal thermal performance in surface-mount industrial designs, maintains full 5 V TTL interoperability, and delivers consistent 8.5 ns propagation delay across temperature - making it the preferred choice for volume-manufactured 5 V backplane interfaces.
Availability
MC74ACT640DW is available at Aetrix Electronics and suitable for industrial backplane interface, legacy system bus bridging, test equipment data routing, and programmable logic interface applications requiring stable component supply and long-term lifecycle support.
Supply support for MC74ACT640DW 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 innovation for automotive, industrial, cloud, medical, and IoT applications.
The MC74ACT640DW belongs to the 74ACT logic family - engineered for high-speed, low-noise 5 V TTL/CMOS interfacing with robust ESD and latch-up immunity in industrial environments.
FAQ
What is the maximum operating frequency supported by the MC74ACT640DW?
The MC74ACT640DW does not specify a maximum clock frequency, but its propagation delay (tPLH/tPHL ≤ 8.5 ns) and output enable time (tPZH ≤ 11.0 ns) support reliable data toggling up to approximately 100 MHz in point-to-point bus configurations with matched trace lengths and proper termination. Actual usable frequency depends on system-level timing margins, including setup/hold requirements of connected devices and PCB trace parasitics - design validation must be performed per application.
Can the MC74ACT640DW operate at 3.3 V supply?
No, the MC74ACT640DW is not rated for 3.3 V operation. Its recommended VCC range is strictly 4.5 V to 5.5 V, and DC characteristics (e.g., VIH = 2.0 V min, VOH ≥ 4.4 V) are guaranteed only within that range. Operating below 4.5 V may result in undefined logic states, increased propagation delay, or failure to meet output drive specifications. For 3.3 V systems, consider the 74LCX640M instead.
How does the T/R and OE pin interaction affect bus behavior in the MC74ACT640DW?
In the MC74ACT640DW, OE is prioritized over T/R: when OE = HIGH, all A and B pins enter high-impedance state regardless of T/R state. When OE = LOW, T/R determines direction - HIGH enables A→B, LOW enables B→A. This hierarchy prevents bus contention during mode transitions and allows safe insertion/removal of boards in live backplanes when OE is asserted first.
Is the MC74ACT640DW pin-compatible with the SN74ACT640N?
Yes, the MC74ACT640DW and SN74ACT640N share identical pin functions and electrical specifications, differing only in package type: SOIC-20W versus PDIP-20. Signal assignments (A0–A7, B0–B7, OE, T/R, VCC, GND) match exactly, and AC/DC parameters are fully aligned per respective datasheets. However, thermal and mechanical integration differs significantly due to package footprint and soldering method.
What is the purpose of the "G" suffix in the ordering code MC74ACT640DWR2G?
The "G" suffix in MC74ACT640DWR2G explicitly denotes Pb-free (lead-free) packaging per JEDEC standards, confirming compliance with RoHS Directive 2011/65/EU. It appears in the date/lot marking (e.g., AWLYYWWG) and indicates the device uses matte tin lead finish and halogen-free mold compound - essential for environmentally regulated manufacturing and reflow process compatibility.
MC74ACT640DW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74ACT
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tube
- 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
MC74ACT640DW FAQ
1.How can I place an order for MC74ACT640DW through Aetrix?
Please submit a Request for Quotation (RFQ) for MC74ACT640DW 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 MC74ACT640DW reliable?
The price and inventory of MC74ACT640DW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC74ACT640DW is usually 5 days.
3.What payment methods are accepted for MC74ACT640DW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC74ACT640DW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC74ACT640DW?
MC74ACT640DW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC74ACT640DW 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 MC74ACT640DW?
For technical support, including MC74ACT640DW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC74ACT640DW requirements.
6.How does Aetrix verify that MC74ACT640DW is sourced from the original manufacturer or authorized distributors?
All MC74ACT640DW 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 MC74ACT640DW meets industry standards.
7.What is the process for return or replacement of MC74ACT640DW?
All MC74ACT640DW units undergo pre-shipment inspection (PSI). If there is an issue with MC74ACT640DW, 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 MC74ACT640DW part is unused and in its original packaging.
Return procedure for MC74ACT640DW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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