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onsemi MC74F623N
- Part No.:
- MC74F623N
- Manufacturer:
- onsemi
- Package:
- -
- Datasheet:
-
MC74F623N.pdf
- Description:
- BUS XCVR SINGLE 8-CH 3-ST 20PIN
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Inventory:5,378
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Product details
Overview
MC74F623N from ON Semiconductor (formerly Motorola) is a non-inverting octal bus transceiver with 3-state outputs, designed for asynchronous bidirectional data transfer between two 8-bit buses. It features dual enable inputs (OEBA, OEAB), 64 mA sink / 15 mA source drive on B-side outputs, and operates across 0°C to +70°C at 4.5–5.5 V supply.
For engineers reviewing the MC74F623N datasheet, pinout, applications, or equivalent options, key selection considerations include its non-inverting logic path, high-current B-bus outputs, dual-enable data latching capability, and SOIC-20 plastic package compatibility with legacy FAST TTL systems.
Technical Context
The MC74F623N implements a dual-directional bus interface using separate A-to-B and B-to-A paths controlled by independent OEBA and OEAB inputs. Its non-inverting architecture preserves signal polarity in both directions, unlike the inverting MC74F620.
When both OEBA and OEAB are asserted low, the device enters transparent latching mode: outputs reinforce inputs, maintaining bus states at high impedance. This behavior enables data storage without external latches, supported by guaranteed 64 mA sink capability on all Bn outputs and 24 mA on An outputs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.5 V to 5.5 V - compatible with standard 5 V TTL systems and tolerant of supply ripple |
| IOH (Bn) | –15 mA - sufficient to drive multiple TTL loads or pull up long traces |
| IOL (Bn) | 64 mA - enables direct interfacing with high-capacitance buses or legacy backplanes |
| tPLH/tPHL (A→B) | 5.5 ns max - ensures sub-6 ns propagation for high-speed 8-bit bus handshaking |
| tPZH (OEBA→An) | 12.0 ns max - defines worst-case enable-to-output transition timing for synchronous control |
| VIH/VIL | 2.0 V / 0.8 V - TTL-compatible input thresholds ensure interoperability with 74LS/74F families |
| ESD Protection | >4000 V HBM - provides robust handling during board assembly and system integration |
Pinout & Package
MC74F623N is housed in a 20-pin plastic SOIC (SO-20 wide) package per case 738-03, with 1.27 mm pitch and gull-wing leads suitable for surface-mount reflow.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A7 | A-side data inputs/outputs | Non-inverting bidirectional I/O pins connected to first 8-bit bus; high-impedance when disabled |
| B0–B7 | B-side data inputs/outputs | Non-inverting bidirectional I/O pins connected to second 8-bit bus; 64 mA sink capability |
| OEBA | Enable A←B direction | Active-low control: enables data flow from B bus to A bus when low |
| OEAB | Enable A→B direction | Active-low control: enables data flow from A bus to B bus when low |
| VCC | Power supply | +4.5 V to +5.5 V DC supply for FAST TTL logic operation |
| GND | Ground reference | Common return path for all I/O and internal circuitry |
Key Features
| Feature | Design Value |
|---|---|
| Non-inverting bidirectional data path | Preserves logic polarity in both A↔B directions-critical for protocol-transparent bus bridging |
| Dual active-low enable inputs | Enables independent control of A→B and B→A data flow, supporting full-duplex or half-duplex modes |
| Simultaneous enable latching | When OEBA = OEAB = L, outputs hold last state-eliminates need for external latch in store-and-forward designs |
| High-current B-bus outputs | 64 mA sink capability supports driving terminated lines or multiple TTL inputs without buffers |
Applications
| Industrial Backplane Interface | Legacy System Bus Extension |
|---|---|
Use Scenario: Interfacing a modern microcontroller bus to an older 8-bit ISA-style backplane with TTL-level signaling. IC Role / Device Role / Timing Role: Bidirectional level-preserving bus transceiver enabling protocol-agnostic data exchange between mismatched subsystems. Use Value: Eliminates need for discrete inverters or additional latches due to non-inverting logic and built-in state-hold capability. | Use Scenario: Extending a CPU local bus to remote peripheral slots in a modular test equipment chassis. IC Role / Device Role / Timing Role: High-drive octal buffer isolating and driving extended trace lengths while maintaining signal integrity. Use Value: 64 mA sink current sustains logic levels over 15 cm PCB traces loaded with multiple TTL inputs. |
| Multi-Processor Shared Memory Link | TTL-Compatible Data Acquisition Hub |
Use Scenario: Arbitrated shared memory access between two 8-bit microcontrollers sharing a common RAM bank. IC Role / Device Role / Timing Role: Direction-controlled bus switch preventing contention during read/write cycles. Use Value: Dual OE inputs allow precise timing control-enabling one processor to drive while the other samples, with sub-12 ns enable delay. | Use Scenario: Aggregating parallel outputs from eight analog-to-digital converters into a single synchronized data stream. IC Role / Device Role / Timing Role: Synchronized capture buffer with simultaneous output enable for glitch-free sampling windows. Use Value: Simultaneous OEBA/OEAB assertion captures and holds ADC outputs without clock skew or metastability risk. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74F245N | Single-directional enable (DIR pin), no dual-OE latching; 64 mA sink only on B-side; identical SOIC-20 footprint | Lacks simultaneous A↔B latching; requires external control logic for bidirectional hold functionality | Choose when simpler direction control suffices and latching is handled elsewhere |
| 74ACT245SCX | CMOS-based (5 V tolerant), lower ICC (20 µA typ), but only 24 mA sink; supports 3.3 V/5 V mixed-mode I/O | Lower drive strength limits use on heavily loaded legacy buses; better for low-power upgrades | Choose for power-sensitive retrofits where bus capacitance ≤ 30 pF per line |
Compared with SN74F245N and 74ACT245SCX, the MC74F623N uniquely supports true bidirectional latching via dual OE inputs and delivers higher B-bus drive-making it irreplaceable in legacy backplane storage applications requiring zero-latency state retention.
Availability
MC74F623N is available at Aetrix Electronics and suitable for industrial backplane interfaces, legacy system bus extensions, and multi-processor shared memory links requiring stable component supply and long-term obsolescence management.
Supply support for MC74F623N 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 delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, and medical applications.
The MC74F623N belongs to the legacy FAST TTL logic family originally developed by Motorola, engineered specifically for high-speed, high-drive bidirectional bus interfacing in industrial control and computer backplane systems.
FAQ
What logic function does the MC74F623N implement?
The MC74F623N implements a non-inverting octal bus transceiver with dual active-low enable inputs (OEBA and OEAB). It allows bidirectional data transfer between two 8-bit buses-A0–A7 and B0–B7-with polarity preservation in both directions. Unlike the inverting MC74F620, the MC74F623N passes signals unchanged, making it suitable for applications requiring transparent logic-level translation without inversion.
Does the MC74F623N support latching behavior?
Yes-the MC74F623N supports transparent latching when both OEBA and OEAB are driven low simultaneously. In this mode, each output reinforces its corresponding input, allowing the A and B buses to retain their last valid logic states even when all other drivers are in high-impedance. This eliminates the need for external latches in store-and-forward bus architectures, a feature confirmed in the device's function table and logic diagram.
What is the maximum output drive capability of the MC74F623N?
The MC74F623N delivers 64 mA sink current on all B0–B7 outputs and 24 mA on A0–A7 outputs, with 15 mA source capability on Bn pins. These values are guaranteed under worst-case conditions (VCC = 4.5 V, TA = +70°C) and enable direct driving of heavily loaded TTL buses, terminated transmission lines, or multiple downstream logic inputs without external buffering.
Is the MC74F623N pin-compatible with other octal transceivers?
The MC74F623N uses a standard 20-pin SOIC (SO-20 wide) package with pinout matching industry-standard octal transceivers like the SN74F245N. However, its dual-OE control scheme differs from the single-DIR pin of the 74F245, meaning PCB layout reuse requires verification of enable signal routing. The pin mapping for A/B I/O and power is identical, but functional compatibility depends on control logic implementation.
What temperature range is specified for the MC74F623N?
The MC74F623N is rated for operation from 0°C to +70°C ambient temperature, consistent with commercial-grade FAST TTL devices. This range is guaranteed per the "Guaranteed Operating Ranges" table in the datasheet, and all electrical parameters-including propagation delay, output drive, and voltage thresholds-are validated across this interval at VCC = 4.5 V to 5.5 V.
MC74F623N 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:
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- Input Type:
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- Current - Output High, Low:
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- Voltage - Supply:
- -
- Operating Temperature:
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MC74F623N FAQ
1.How can I place an order for MC74F623N through Aetrix?
Please submit a Request for Quotation (RFQ) for MC74F623N 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 MC74F623N reliable?
The price and inventory of MC74F623N are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC74F623N is usually 5 days.
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4.How is shipping managed for MC74F623N?
MC74F623N orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC74F623N 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 MC74F623N?
For technical support, including MC74F623N datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC74F623N requirements.
6.How does Aetrix verify that MC74F623N is sourced from the original manufacturer or authorized distributors?
All MC74F623N 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 MC74F623N meets industry standards.
7.What is the process for return or replacement of MC74F623N?
All MC74F623N units undergo pre-shipment inspection (PSI). If there is an issue with MC74F623N, 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 MC74F623N part is unused and in its original packaging.
Return procedure for MC74F623N:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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