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onsemi 74F544SPC
- Part No.:
- 74F544SPC
- Manufacturer:
- onsemi
- Package:
- 24-DIP (0.300", 7.62mm)
- Datasheet:
-
74F544SPC.pdf
- Description:
- IC TRANSCEIVER INVERT 5.5V 24DIP
- Quantity:
- Payment:
- Shipping:
Inventory:4,834
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Product details
Overview
74F544SPC from Fairchild Semiconductor is an octal registered transceiver with dual-directional 3-state data flow control, featuring separate A-to-B and B-to-A latch enable (LEAB/LEBA) and output enable (OEAB/OEBA) inputs, A outputs rated for 24 mA sink current, B outputs rated for 64 mA sink current, and guaranteed inversion of data in both directions - used in bidirectional bus interface applications between microprocessor address/data buses and peripheral subsystems.
For engineers reviewing the 74F544SPC datasheet, pinout, applications, or equivalent options, key selection criteria include independent A/B register control timing, 3-state output drive strength asymmetry (24 mA vs. 64 mA), propagation delays under 14.5 ns, latch setup/hold times of 3.0 ns, and compatibility with +5 V ±10% TTL logic systems.
Technical Context
The 74F544SPC implements two independent 8-bit D-type latch banks - one for A-to-B data path and one for B-to-A - each with dedicated enable (CEAB/CEBA), latch (LEAB/LEBA), and output (OEAB/OEBA) controls. It operates strictly at VCC = +4.5 V to +5.5 V with input thresholds VIH ≥ 2.0 V and VIL ≤ 0.8 V.
All outputs are 3-state with active-low enables; A-side outputs (A0–A7) drive up to 24 mA low, while B-side outputs (B0–B7) drive up to 64 mA low. Data inversion occurs on both paths: A inputs appear inverted at B outputs, and B inputs appear inverted at A outputs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | +4.5 V to +5.5 V - ensures compatibility with standard 5 V TTL power domains |
| IOH / IOL (A-side) | −1 mA / 24 mA - supports driving standard TTL loads from A outputs |
| IOH / IOL (B-side) | −3 mA / 64 mA - enables direct interfacing with higher-current peripherals via B outputs |
| tPLH / tPHL (max) | 14.5 ns - defines worst-case propagation delay for latch-transparent mode |
| tPZH / tPHZ (max) | 12.0 ns / 9.0 ns - determines minimum time to enable/disable 3-state outputs |
| tS / tH | 3.0 ns - constrains minimum data setup and hold window relative to latch edge |
| Operating Temp | 0°C to +70°C - specifies commercial-grade ambient range for stable bus operation |
Pinout & Package
74F544SPC is housed in a 24-lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-100 compliant, 0.300 inch wide, with through-hole mounting and standard 0.1 inch pin pitch.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4, 5, 6, 7, 8 | A0–A7 Inputs / B-to-A Outputs | 8-bit bidirectional port: driven by B latches when OEBA = LOW; source data to B latches when CEBA = LOW |
| 9, 10 | OEBA, CEBA | B-to-A Output Enable (active LOW) and Enable (active LOW) - control B→A data visibility and latching |
| 11, 12 | GND, VCC | Ground reference and +5 V supply pins - require local decoupling per high-speed TTL practice |
| 13, 14, 15, 16, 17, 18, 19, 20 | B0–B7 Inputs / A-to-B Outputs | 8-bit bidirectional port: driven by A latches when OEAB = LOW; source data to A latches when CEAB = LOW |
| 21, 22 | OEAB, CEAB | A-to-B Output Enable (active LOW) and Enable (active LOW) - control A→B data visibility and latching |
| 23, 24 | LEBA, LEAB | B-to-A and A-to-B Latch Enable (active LOW) - capture data on falling edge into respective latch banks |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent latch banks | Enables simultaneous A→B and B→A data staging without contention, critical for full-duplex bus arbitration |
| Asymmetric output drive capability | B-side 64 mA sink supports legacy peripherals (e.g., EPROMs, latches); A-side 24 mA matches microprocessor bus loading |
| Full 3-state control per direction | Separate OEAB/OEBA allows independent tri-stating of each port - essential for multi-master bus sharing |
| Data inversion on both paths | Eliminates need for external inverters in complemented bus architectures (e.g., address strobe inversion) |
Applications
| Microprocessor Bus Interface | Memory Expansion Subsystem |
|---|---|
Use Scenario: Interfacing an 8-bit microprocessor data bus to external peripherals requiring isolated, direction-controlled data transfer. IC Role / Device Role: Bidirectional registered transceiver managing data flow between CPU AD bus and peripheral address/data lines. Use Value: Prevents bus contention during read/write transitions using independent CE/OE controls and latch staging. | Use Scenario: Expanding RAM/ROM capacity in embedded controllers where address latching and data isolation are required. IC Role / Device Role: Registered transceiver isolating memory address/data paths while supporting multiplexed bus protocols. Use Value: Enables clean separation of memory read and write cycles via LEAB/LEBA timing control and 3-state output disable. |
| I/O Port Expansion | Legacy Peripheral Bridge |
Use Scenario: Adding parallel I/O ports to microcontrollers lacking sufficient native GPIO, especially where bus loading must be managed. IC Role / Device Role: Directionally controlled data buffer with latch storage for synchronous I/O handshaking. Use Value: Provides 8-bit latched input capture and 3-state output drive with asymmetric current capability (64 mA B-side). | Use Scenario: Connecting modern logic to legacy industrial peripherals (e.g., stepper motor drivers, display controllers) requiring inverted data and high-sink drive. IC Role / Device Role: Inverting registered transceiver delivering level-shifted, latched, and high-current drive signals. Use Value: Delivers 64 mA sink on B outputs and built-in inversion - eliminates discrete inverters and boost transistors. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal registered transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74F544N | Same logic function, identical pinout, same PDIP-24 package (N24C), but manufactured by Texas Instruments | No functional difference; validated for drop-in replacement in legacy 74F designs | Select when TI-sourced 74F family continuity is required or preferred for supply chain diversification |
| 74ACT544PC | Advanced CMOS version: 5 V tolerant, lower ICC (20 mA typical), faster tPLH/tPHL (5.5 ns max), but B-side IOL = 24 mA only (not 64 mA) | Not suitable where >24 mA B-side drive is required; better for low-power, high-speed systems with matched load profiles | Select only if B-side current demand ≤24 mA and reduced power consumption is prioritized over legacy drive strength |
Compared with SN74F544N, 74F544SPC offers identical functionality and mechanical fit; compared with 74ACT544PC, 74F544SPC provides higher B-side drive (64 mA vs. 24 mA) at the cost of higher ICC and slower speed - making it preferable for legacy industrial bus interfaces demanding robust current delivery.
Availability
74F544SPC is available at Aetrix Electronics and suitable for microprocessor bus interface, memory expansion subsystem, and legacy peripheral bridge applications requiring stable component supply across long-lifecycle industrial programs.
Supply support for 74F544SPC 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
Fairchild Semiconductor was a U.S.-based semiconductor company specializing in analog and mixed-signal ICs, power management, and logic families before its acquisition by ON Semiconductor in 2016.
The 74F544SPC belongs to Fairchild's 74F Fast TTL logic family, designed for high-speed, low-noise bidirectional bus interfacing in industrial and computing systems operating at 5 V.
FAQ
What is the logic function of the 74F544SPC?
The 74F544SPC is an octal registered transceiver containing two independent 8-bit D-type latch banks - one for A-to-B and one for B-to-A data paths - with separate latch enable, enable, and output enable controls per direction, and built-in inversion on both paths. It operates as a bidirectional, latched, 3-state bus interface device within 5 V TTL systems.
Does the 74F544SPC support 3.3 V operation?
No, the 74F544SPC is a Fast TTL device specified only for VCC = +4.5 V to +5.5 V. It does not support 3.3 V operation, lacks 3.3 V input tolerance, and may malfunction or suffer damage if powered at 3.3 V. For 3.3 V systems, consider ACT or LVT logic families instead of the 74F544SPC.
What is the maximum sink current capability of the B outputs on the 74F544SPC?
The B outputs (B0–B7) of the 74F544SPC are rated for a maximum sink current of 64 mA per pin under DC conditions, as confirmed in the Absolute Maximum Ratings and DC Electrical Characteristics tables of the Fairchild DS009555 datasheet. This rating enables direct drive of legacy peripherals such as EPROMs and LED arrays without external buffers.
Is the 74F544SPC pin-compatible with the SN74F544N?
Yes, the 74F544SPC and SN74F544N share identical pin assignments, electrical specifications, and PDIP-24 (N24C) package dimensions. Both comply with JEDEC MS-100 and support drop-in replacement in existing PCB layouts without modification - confirmed by cross-referencing Fairchild DS009555 and TI SN74F544 datasheets.
What does "registered transceiver" mean for the 74F544SPC?
"Registered transceiver" means the 74F544SPC incorporates internal D-type latches on both A-to-B and B-to-A data paths, allowing temporary storage of data synchronized to latch-enable signals (LEAB/LEBA). Unlike simple transceivers, it provides edge-triggered data capture and holds values independently per direction - enabling precise timing control in synchronous bus protocols.
74F544SPC Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74F
- Package/Case:
- 24-DIP (0.300", 7.62mm)
- 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:
- 3mA, 24mA; 3mA, 64mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 24-PDIP
74F544SPC FAQ
1.How can I place an order for 74F544SPC through Aetrix?
Please submit a Request for Quotation (RFQ) for 74F544SPC 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 74F544SPC reliable?
The price and inventory of 74F544SPC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74F544SPC is usually 5 days.
3.What payment methods are accepted for 74F544SPC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74F544SPC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74F544SPC?
74F544SPC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74F544SPC 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 74F544SPC?
For technical support, including 74F544SPC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74F544SPC requirements.
6.How does Aetrix verify that 74F544SPC is sourced from the original manufacturer or authorized distributors?
All 74F544SPC 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 74F544SPC meets industry standards.
7.What is the process for return or replacement of 74F544SPC?
All 74F544SPC units undergo pre-shipment inspection (PSI). If there is an issue with 74F544SPC, 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 74F544SPC part is unused and in its original packaging.
Return procedure for 74F544SPC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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