My Inquiry
My Account
onsemi MC74ACT648N
- Part No.:
- MC74ACT648N
- Manufacturer:
- onsemi
- Package:
- -
- Datasheet:
-
MC74ACT648N.pdf
- Description:
- REGISTERED BUS TRANSCEIVER, ACT
- Quantity:
- Payment:
- Shipping:
Inventory:3,032
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
MC74ACT648N from ON Semiconductor (formerly Motorola) is an octal registered bus transceiver with 3-state outputs and inverting logic function, designed for bidirectional data flow control between two 8-bit buses. It integrates independent D-type flip-flops per channel, supports real-time and registered data transfer modes, provides ±24 mA output drive, and operates at 4.5–5.5 V supply - used in backplane interface, memory-mapped I/O, and programmable logic interconnect systems.
For engineers reviewing the MC74ACT648N datasheet, pinout, applications, or equivalent options, this page delivers verified functional architecture, timing-critical AC/DC specifications, package-validated pin roles, and direct alternative options for industrial bus buffering and register-controlled data routing.
Technical Context
The MC74ACT648N implements dual 8-bit registered transceivers with separate clock inputs (CAB, CBA) enabling asynchronous loading of A- or B-bus data into internal D-flip-flops on LOW-to-HIGH transitions. Its DIR and G inputs jointly control direction and 3-state output enable, while SAB/SBA select real-time vs. stored data paths.
It features true/inverting data path selection, independent A/B register storage, and propagation delays as low as 1.5 ns (min) with 11.5 ns (max) bus-to-bus delay at 5.0 V/85°C. All outputs meet ACT-series TTL-compatible voltage thresholds and drive strength, supporting mixed-voltage system interfacing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5–5.5 V - ensures compatibility with standard 5 V TTL and mixed-signal systems without level-shifting. |
| Output Drive | ±24 mA - sufficient to directly drive multiple TTL loads or terminate short PCB traces without external buffers. |
| Propagation Delay | 1.5–15.5 ns (Clock-to-Bus) - enables reliable operation in high-speed synchronous bus architectures up to ~60 MHz. |
| Input Thresholds | VIH = 2.0 V, VIL = 0.8 V @ 5 V - guarantees noise margin >0.4 V in industrial environments with ground bounce. |
| 3-State Enable Time | tPZH = 1.0–12.5 ns - allows fast bus arbitration and prevents contention during dynamic reconfiguration. |
| Operating Temperature | –40°C to +85°C - qualified for extended industrial temperature range without derating. |
| Input Capacitance | 4.5 pF - minimizes signal loading on upstream drivers and preserves edge integrity in dense layouts. |
Pinout & Package
MC74ACT648N is housed in a 24-pin plastic dual in-line package (PDIP), case 724-03, 300 mil width, with 0.1 inch lead pitch and through-hole mounting. Pin 1 is marked by notch or dot; leads are tin-lead plated for solderability.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (CAB) | A→B Clock Input | Triggers load of A-bus data into B-register on rising edge; controls real-time or stored A→B transfer. |
| 2 (SAB) | A→B Select Input | When active LOW, enables stored A-data output to B-bus; HIGH selects real-time A→B pass-through. |
| 3 (DIR) | Direction Control | LOW enables A→B direction; HIGH enables B→A direction - determines primary data flow orientation. |
| 4–11 (A0–A7) | A-Bus Data I/O | Bi-directional pins serving as inputs to A-register or outputs from A-register; driven by CAB/CBA clocks. |
| 12 (GND) | Ground Reference | Primary power return path; must be low-impedance and decoupled near VCC pin for noise immunity. |
| 13–20 (B0–B7) | B-Bus Data I/O | Bi-directional pins serving as inputs to B-register or outputs from B-register; driven by CBA/CAB clocks. |
| 21 (G) | Output Enable | Active LOW global 3-state control - disables all A/B outputs simultaneously to isolate buses. |
| 22 (SBA) | B→A Select Input | When active LOW, enables stored B-data output to A-bus; HIGH selects real-time B→A pass-through. |
| 23 (CBA) | B→A Clock Input | Triggers load of B-bus data into A-register on rising edge; controls real-time or stored B→A transfer. |
| 24 (VCC) | Power Supply | +4.5 to +5.5 V DC input; requires local 0.1 µF ceramic decoupling capacitor to suppress switching noise. |
Key Features
| Feature | Design Value |
|---|---|
| Independent A/B registers | Enables simultaneous capture and hold of data from both buses - critical for handshake-free burst transfers. |
| Multiplexed real-time & stored transfer | Per-channel SAB/SBA control allows dynamic switching between live bus monitoring and buffered register readout. |
| Inverting 3-state outputs | Guarantees logic-level compatibility with legacy TTL loads while preventing bus contention during disable. |
| ACT-series speed/power balance | Delivers 5 V TTL-compatible performance with <80 µA quiescent ICC - optimized for low-noise industrial control. |
| Industrial temperature rating | Validated operation from –40°C to +85°C - suitable for uncooled enclosures and outdoor embedded systems. |
Applications
| Backplane Data Routing | Programmable Logic Interconnect |
|---|---|
Use Scenario: Isolating and synchronizing data between CPU and peripheral modules across a 16-bit parallel backplane. IC Role / Device Role / Timing Role: Registered transceiver managing A↔B bus handshaking with clock-gated register staging and 3-state isolation. Use Value: Eliminates metastability risk during asynchronous module insertion/removal while maintaining deterministic 11.5 ns max bus-to-bus latency. |
Use Scenario: Interfacing FPGA I/O banks with microcontroller peripherals requiring registered address/data latching. IC Role / Device Role / Timing Role: Bidirectional register buffer providing setup/hold time margin for FPGA-to-MCU communication at 50 MHz. Use Value: Enables reliable capture of MCU address strobes using CAB/CBA clocks, reducing FPGA timing closure effort by 30%. |
| Memory-Mapped I/O Expansion | Industrial PLC Bus Interface |
Use Scenario: Expanding GPIO count via parallel I/O port connected to microcontroller's external memory bus. IC Role / Device Role / Timing Role: Octal transceiver with DIR/G-controlled direction and SAB/SBA-selectable register mode for address/data multiplexing. Use Value: Allows single 8-bit port to serve dual roles (input latch + output driver) without external glue logic or additional control lines. |
Use Scenario: Connecting distributed I/O modules to a central PLC controller over a ruggedized parallel fieldbus. IC Role / Device Role / Timing Role: Robust bus transceiver with ±24 mA drive and –40°C to +85°C operation for noise-immune sensor/actuator data exchange. Use Value: Maintains signal integrity across 30 cm ribbon cables in EMI-heavy factory environments without repeaters. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar registered bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ACT648N | Identical pinout, AC/DC specs, and logic function; manufactured by Texas Instruments under second-source agreement. | No functional deviation - validated drop-in replacement in all Motorola-designated circuits. | Select when TI supply chain alignment or dual-sourcing strategy is required. |
| 74F648PC | F-series part with faster 8 ns max tPLH but higher ICC (30 mA typical) and narrower 4.75–5.25 V supply range. | Suitable only where speed >100 MHz timing margins exist; not recommended for thermally constrained or battery-backed designs. | Choose only if propagation delay is the dominant constraint and power/thermal budget permits. |
Compared with MC74ACT648N, SN74ACT648N offers identical functionality and qualification with full supply-chain redundancy, while 74F648PC trades higher static power and tighter supply tolerance for marginal speed gain - making MC74ACT648N optimal for balanced industrial reliability and timing predictability.
Availability
MC74ACT648N is available at Aetrix Electronics and suitable for backplane routing, programmable logic interconnect, and memory-mapped I/O expansion requiring stable component supply across long-lifecycle industrial programs.
Supply support for MC74ACT648N 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
ON Semiconductor is a global semiconductor supplier specializing in energy-efficient electronics, with leadership in analog, power management, and logic solutions for automotive, industrial, and cloud infrastructure markets.
The MC74ACT648N belongs to the ACT-family of advanced CMOS logic devices, engineered for high-speed, low-power, TTL-compatible operation in noise-sensitive industrial control and instrumentation systems.
FAQ
What is the maximum clock frequency supported by the MC74ACT648N?
The MC74ACT648N does not specify a maximum clock frequency in its datasheet; instead, it defines minimum clock pulse width (tw = 5.0 ns min at 5.0 V) and setup/hold times (ts = 4.0 ns, th = 2.0 ns). These parameters support reliable operation up to approximately 60 MHz in well-designed PCB layouts with controlled impedance and proper termination - confirmed by AC timing analysis at –40°C to +85°C.
Does the MC74ACT648N support hot-swapping or live insertion?
The MC74ACT648N is not rated for hot-swapping. Its absolute maximum ratings do not include I/O stress during power-up sequencing, and no bus-hold or power-off protection circuitry is integrated. For live-insertion applications, external series resistors and careful power-rail ramp control are required - the MC74ACT648N itself must be powered before asserting any input signals.
How does the DIR pin interact with the SAB and SBA control signals on the MC74ACT648N?
On the MC74ACT648N, DIR sets the primary data direction (LOW = A→B, HIGH = B→A), while SAB and SBA independently select data source per direction: SAB = LOW enables stored A-data to B-bus when DIR = LOW; SBA = LOW enables stored B-data to A-bus when DIR = HIGH. All three signals must be stable before clock edges to avoid metastable output states.
Can the MC74ACT648N operate at 3.3 V supply voltage?
No - the MC74ACT648N is specified only for 4.5–5.5 V operation. Its VIH/VIL thresholds (2.0 V/0.8 V) and output drive capability (±24 mA) are characterized exclusively within that range. Attempting 3.3 V operation results in undefined logic states, reduced noise margin, and potential failure to meet AC timing specs; use MC74AC648N for 3.3 V–5.5 V flexible supply support.
What is the purpose of the "inverting" designation in the MC74ACT648N part number?
The "inverting" label refers to the output polarity of the 3-state drivers: when enabled, outputs present logically inverted versions of internal register contents. This matches standard TTL bus transceiver conventions and ensures compatibility with legacy systems expecting active-low signaling on shared data lines - verified in the logic symbol and truth table of the MC74ACT648N datasheet.
MC74ACT648N Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- *
- Package/Case:
- -
- Packaging:
- Bulk
- Product Status:
- Active
- Logic Type:
- -
- Number of Elements:
- -
- Number of Bits per Element:
- -
- Input Type:
- -
- Output Type:
- -
- Current - Output High, Low:
- -
- Voltage - Supply:
- -
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- -
- Supplier Device Package:
- -
MC74ACT648N FAQ
1.How can I place an order for MC74ACT648N through Aetrix?
Please submit a Request for Quotation (RFQ) for MC74ACT648N 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 MC74ACT648N reliable?
The price and inventory of MC74ACT648N are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC74ACT648N is usually 5 days.
3.What payment methods are accepted for MC74ACT648N?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC74ACT648N transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC74ACT648N?
MC74ACT648N orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC74ACT648N 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 MC74ACT648N?
For technical support, including MC74ACT648N datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC74ACT648N requirements.
6.How does Aetrix verify that MC74ACT648N is sourced from the original manufacturer or authorized distributors?
All MC74ACT648N 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 MC74ACT648N meets industry standards.
7.What is the process for return or replacement of MC74ACT648N?
All MC74ACT648N units undergo pre-shipment inspection (PSI). If there is an issue with MC74ACT648N, 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 MC74ACT648N part is unused and in its original packaging.
Return procedure for MC74ACT648N:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MC74ACT648N Tags
-
SN74LVC1G17DBVR
Texas Instruments
-
SN74LVC1G07DCKR
Texas Instruments
-
SN74LVC1G17DCKR
Texas Instruments
-
SN74LVC1G07DBVR
Texas Instruments
-
SN74LVC1G125DCKR
Texas Instruments
-
SN74AHCT1G126DBVR
Texas Instruments
-
SN74LVC1G125DBVR
Texas Instruments
-
SN74AHCT1G125DBVR
Texas Instruments
-
SN74LVC2G17DBVR
Texas Instruments
-
SN74LVC2G07DCKR
Texas Instruments
-
SN74LVC1G34DCKR
Texas Instruments
-
SN74LVC2G17DCKR
Texas Instruments
Tech Hub
Counterfeit components can hide behind convincing markings and passing basic function tests. This engineering reference covers source traceability, external inspection, X-ray, XRF, electrical testing, …
A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
