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onsemi 74ACTQ245PC
- Part No.:
- 74ACTQ245PC
- Manufacturer:
- onsemi
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
74ACTQ245PC.pdf
- Description:
- IC TXRX NON-INVERT 5.5V 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:4,986
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Product details
Overview
74ACTQ245PC from Fairchild Semiconductor is an octal bidirectional transceiver with 3-STATE inputs/outputs, designed for bus-oriented digital systems. It operates at 4.5V–5.5V supply, delivers ±24 mA drive strength per I/O, and features guaranteed pin-to-pin skew ≤1.0 ns at 5.0V. Its Quiet Series technology suppresses simultaneous switching noise, enabling reliable data transfer in high-density PCB layouts such as backplane interfaces and memory address buffering.
For engineers reviewing the 74ACTQ245PC datasheet, pinout, applications, or equivalent options, key selection criteria include its 5V-only operation, 3-STATE bidirectional control via OE/T/R inputs, dynamic input thresholds (VIHD = 2.2V, VILD = 0.8V at 5V), and PDIP-20 package compatibility with legacy through-hole assembly processes.
Technical Context
The 74ACTQ245PC implements a non-inverting bidirectional buffer architecture controlled by two independent logic inputs: Output Enable (OE) places both A and B ports in high-impedance state when HIGH, while Transmit/Receive (T/R) selects direction-HIGH enables A→B flow, LOW enables B→A flow. All eight channels share identical timing and drive characteristics.
Its Quiet Series design integrates GTO output control and undershoot correction with a split ground bus to reduce dynamic threshold variation and limit VOLP (max dynamic low output voltage) to 1.5 V and VOLV (min dynamic low output voltage) to 0.6 V under simultaneous switching conditions at 5.0 V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - Valid only within this narrow range; not functional below 4.5 V or above 5.5 V. |
| Output Drive Strength | ±24 mA per I/O - Sinks or sources up to 24 mA, sufficient to drive standard TTL loads and 50-pF bus capacitances. |
| Propagation Delay | 5.5 ns max (tPHL/tPLH at 5V, CL = 50 pF) - Enables reliable operation in 100+ MHz bus systems with tight timing margins. |
| Output Skew | ≤1.0 ns - Guarantees synchronized switching across all eight channels, critical for byte-wide data integrity. |
| Dynamic Input Thresholds | VIHD = 2.2 V, VILD = 0.8 V at 5V - Provides 1.4 V noise margin against ground bounce and crosstalk in noisy environments. |
| Quiescent Supply Current | 40 µA max - Ultra-low static power draw supports low-power standby modes without external gating. |
| Input/Output Capacitance | CI/O = 15 pF - Minimizes capacitive loading on driving sources and reduces signal rise/fall time degradation. |
Pinout & Package
74ACTQ245PC uses a 20-lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001 compliant, 0.300" wide, with 0.100" lead pitch and through-hole mounting. Pin 1 is marked by a notch or dot; pin numbering follows standard DIP convention (counterclockwise from top-left).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (OE) | Output Enable Input | Active-HIGH global disable: drives both A and B ports into high-Z when HIGH; required for bus isolation. |
| 2–9 (A0–A7) | Side A I/O Terminals | Bidirectional 3-STATE pins: function as inputs or outputs depending on T/R state; each rated for ±24 mA. |
| 10 (GND) | Ground Reference | Primary return path for all I/O and internal logic; split ground bus design minimizes switching noise coupling. |
| 11–18 (B0–B7) | Side B I/O Terminals | Bidirectional 3-STATE pins: mirror A-side behavior; enable full byte-wide bidirectional data transfer between separate buses. |
| 19 (T/R) | Transmit/Receive Control | Active-HIGH = A→B direction; Active-LOW = B→A direction; determines real-time data flow polarity. |
| 20 (VCC) | Power Supply | +5V nominal supply input; must be decoupled locally (0.1 µF ceramic + 10 µF tantalum) due to Quiet Series transient current demands. |
Key Features
| Feature | Design Value |
|---|---|
| Quiet Series Noise Suppression | GTO output control + undershoot corrector + split ground bus reduce simultaneous switching noise (SSN) to <1.5 V peak deviation. |
| Guaranteed Pin-to-Pin Skew | ≤1.0 ns across all eight channels ensures deterministic byte alignment in synchronous bus transfers. |
| Enhanced Latch-Up Immunity | Meets JEDEC JESD78 Class II (>200 mA) - prevents destructive latch-up during ESD or overvoltage transients. |
| Faster Propagation vs ACT245 | Typical tPLH/tPHL reduced by ~15% - improves setup/hold timing margins in high-speed 5V logic systems. |
| 3-STATE Bus Driving Capability | Drives standard TTL loads and 50-pF transmission lines directly - eliminates need for external bus buffers in mid-speed applications. |
Applications
| Memory Address Buffering | Backplane Data Interface |
|---|---|
Use Scenario: Isolating and driving CPU address lines to multiple memory modules on a shared bus. IC Role / Device Role / Timing Role: Bidirectional transceiver managing address propagation from processor to memory banks with precise timing control via OE/T/R. Use Value: ±24 mA drive strength ensures clean signal edges across long traces; low skew preserves address byte coherence during burst accesses. | Use Scenario: Enabling bidirectional data exchange between line cards in a modular telecom chassis. IC Role / Device Role / Timing Role: Bus interface transceiver synchronizing data flow between upstream/downstream slots using shared parallel backplane wiring. Use Value: Quiet Series noise suppression prevents false triggering in adjacent control lines; 3-STATE isolation avoids bus contention during hot-swap events. |
| Industrial PLC I/O Expansion | Legacy System Bus Translation |
Use Scenario: Extending digital I/O capacity of programmable logic controllers using isolated 5V parallel buses. IC Role / Device Role / Timing Role: Level-shifting and direction-controlled buffer between microcontroller GPIO and field I/O modules. Use Value: Guaranteed 4.5–5.5V operation tolerates industrial supply ripple; high noise immunity sustains reliability in electrically noisy factory environments. | Use Scenario: Interfacing modern 5V peripherals with older 5V TTL-based mainframes or test equipment. IC Role / Device Role / Timing Role: Protocol-transparent bidirectional bridge maintaining signal integrity across legacy bus segments. Use Value: Pin-compatible replacement for obsolete 74ACT245 variants; PDIP-20 footprint allows drop-in upgrade without PCB redesign. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bidirectional transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 74ACT245PC | No Quiet Series features; higher simultaneous switching noise (VOLP up to 2.2 V); no GTO or undershoot correction. | Lacks dynamic noise suppression - unsuitable where adjacent analog or clock lines require strict SSN control. | Select 74ACT245PC only if cost sensitivity outweighs noise performance requirements and layout has ample ground separation. |
| SN74ACT245N | Identical electrical specs and pinout; manufactured by Texas Instruments; same PDIP-20 package and 4.5–5.5V operation. | Functionally interchangeable; TI's version exhibits comparable AC timing but lacks Fairchild's documented Quiet Series characterization. | Choose SN74ACT245N when dual-sourcing is required and board-level noise validation has already been completed with TI's device. |
Compared with 74ACTQ245PC, 74ACT245PC offers lower cost but sacrifices guaranteed SSN suppression and dynamic threshold stability, while SN74ACT245N provides second-source availability with identical DC/AC behavior but less detailed noise waveform documentation.
Availability
74ACTQ245PC is available at Aetrix Electronics and suitable for memory address buffering, backplane data interfaces, industrial PLC I/O expansion, and legacy system bus translation requiring stable component supply and through-hole assembly compatibility.
Supply support for 74ACTQ245PC 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 high-performance analog and logic ICs before its acquisition by ON Semiconductor in 2016. Its legacy products remain widely deployed in industrial and communications infrastructure.
The 74ACTQ245PC belongs to Fairchild's Quiet Series ACT family, engineered specifically for noise-sensitive 5V bus applications where simultaneous switching noise and timing skew must be tightly controlled in dense PCB layouts.
FAQ
What is the operating voltage range for the 74ACTQ245PC?
The 74ACTQ245PC operates strictly within 4.5 V to 5.5 V. It is not functional below 4.5 V or above 5.5 V, and its AC and DC specifications-including VOH, VOL, propagation delay, and noise immunity-are guaranteed only across this range. This differs from the broader 2.0–6.0 V range of the ACQ variant, making 74ACTQ245PC suitable exclusively for robust 5V systems.
How does the 74ACTQ245PC handle bidirectional data flow control?
The 74ACTQ245PC uses two dedicated control inputs: OE (Output Enable, active-HIGH) disables both A and B ports into high-impedance state, while T/R (Transmit/Receive, active-HIGH) selects direction-HIGH enables A→B transfer, LOW enables B→A transfer. This dual-control scheme allows precise, cycle-by-cycle bus arbitration without external logic, and is fully implemented in the 74ACTQ245PC's internal circuitry.
What makes the 74ACTQ245PC "Quiet Series," and how is that verified?
The 74ACTQ245PC incorporates Fairchild's proprietary Quiet Series technology, including GTO output control, undershoot correction, and a split ground bus. These features are validated by measured dynamic noise parameters: VOLP ≤1.5 V and VOLV ≥0.6 V under worst-case simultaneous switching (per Figure 1 and Figure 2 in DS010236), confirming reduced ground bounce and improved dynamic threshold stability versus standard ACT devices.
Is the 74ACTQ245PC pin-compatible with standard 74ACT245 devices?
Yes, the 74ACTQ245PC shares identical pinout, DC/AC electrical specifications, and functional behavior with standard 74ACT245 variants such as 74ACT245PC and SN74ACT245N. Its Quiet Series enhancements are implemented internally without altering pin assignment, package dimensions, or logic truth table-making it a direct drop-in replacement where noise reduction is needed.
What package type and mounting style does the 74ACTQ245PC use?
The 74ACTQ245PC uses a 20-lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001 compliant, 0.300" wide, with through-hole leads spaced at 0.100". It is designed for wave soldering or hand-soldering onto standard PCBs and remains compatible with legacy socketed designs and automated insertion equipment used in industrial electronics manufacturing.
74ACTQ245PC Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74ACTQ
- Package/Case:
- 20-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Logic Type:
- Transceiver, Non-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:
- Through Hole
- Supplier Device Package:
- 20-PDIP
74ACTQ245PC FAQ
1.How can I place an order for 74ACTQ245PC through Aetrix?
Please submit a Request for Quotation (RFQ) for 74ACTQ245PC 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 74ACTQ245PC reliable?
The price and inventory of 74ACTQ245PC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74ACTQ245PC is usually 5 days.
3.What payment methods are accepted for 74ACTQ245PC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74ACTQ245PC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74ACTQ245PC?
74ACTQ245PC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74ACTQ245PC 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 74ACTQ245PC?
For technical support, including 74ACTQ245PC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74ACTQ245PC requirements.
6.How does Aetrix verify that 74ACTQ245PC is sourced from the original manufacturer or authorized distributors?
All 74ACTQ245PC 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 74ACTQ245PC meets industry standards.
7.What is the process for return or replacement of 74ACTQ245PC?
All 74ACTQ245PC units undergo pre-shipment inspection (PSI). If there is an issue with 74ACTQ245PC, 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 74ACTQ245PC part is unused and in its original packaging.
Return procedure for 74ACTQ245PC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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