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onsemi 74ACTQ244PC
- Part No.:
- 74ACTQ244PC
- Manufacturer:
- onsemi
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
74ACTQ244PC.pdf
- Description:
- IC BUFF NON-INVERT 5.5V 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:4,898
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Product details
Overview
74ACTQ244PC from Fairchild Semiconductor is an octal 3-STATE buffer/line driver in PDIP-20 package, designed for memory address driving, clock distribution, and bus transceiver applications with simultaneous switching noise suppression. It operates at 4.5V–5.5V, delivers ±24 mA output drive, guarantees <1.0 ns output-to-output skew, and features Quiet Series™ technology with dynamic threshold control.
For engineers reviewing the 74ACTQ244PC datasheet, pinout, applications, or equivalent options, this page provides verified electrical specs, pin-level design meaning, real-world use scenarios, and validated alternative options for high-density digital interface designs requiring low-noise bus driving.
Technical Context
The 74ACTQ244PC implements dual 4-bit non-inverting buffers with independent 3-STATE enable controls (OE1/OE2), each gating four outputs (O0–O3 and O4–O7). Its Quiet Series™ architecture integrates GTO™ output control and undershoot correction to suppress simultaneous switching noise (SSN) during high-speed transitions.
It supports guaranteed dynamic input thresholds (VIHD = 2.2 V, VILD = 0.8 V at VCC = 5.0 V), delivers 5.5 ns max propagation delay (tPLH/tPHL), and maintains ≤0.44 V VOL at IOL = 24 mA - enabling robust TTL/CMOS bus interfacing without external termination.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.5 V to 5.5 V - compatible with standard 5 V TTL/CMOS logic rails; not rated for 3.3 V operation. |
| Output Drive | ±24 mA - sufficient to directly drive 50 pF loads at full speed without external buffers. |
| Propagation Delay | ≤7.0 ns (max, VCC = 5.0 V, CL = 50 pF) - enables sub-100 MHz bus timing margins. |
| Output Skew | ≤1.0 ns (guaranteed) - ensures deterministic timing across all eight outputs for synchronous bus interfaces. |
| Quiet Output Noise | VOLP ≤ 1.5 V, VOLV ≥ −1.2 V (dynamic) - suppresses ground bounce and crosstalk in dense PCB layouts. |
| Input Thresholds | VIHD = 2.2 V, VILD = 0.8 V (at VCC = 5.0 V) - provides 1.4 V noise margin against TTL-compatible inputs. |
| 3-STATE Leakage | ±2.5 µA (max, VI = VIL/V IH) - prevents bus contention leakage current in high-impedance mode. |
Pinout & Package
74ACTQ244PC uses a 20-pin Plastic Dual-In-Line Package (PDIP), JEDEC MS-001 compliant, 0.300" wide body, with through-hole mounting and standard 0.1" pin pitch.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | OE1, OE2 | Active-Low 3-STATE enable inputs - independently disable first four (pins 2–5) or last four outputs (pins 13–16). |
| 2–5, 13–16 | I0–I3, I4–I7 | Non-inverting data inputs - accept TTL/CMOS logic levels; no internal pull-ups/downs. |
| 6–9, 12–15 | O0–O3, O4–O7 | 3-STATE buffered outputs - sink/source ±24 mA; high-impedance when corresponding OE is HIGH. |
| 10 | GND | Dedicated ground reference - split ground bus design minimizes SSN coupling between output groups. |
| 20 | VCC | Power supply - must be decoupled locally (0.1 µF ceramic + 10 µF tantalum) per datasheet layout guidance. |
Key Features
| Feature | Design Value |
|---|---|
| Quiet Series™ noise suppression | Guaranteed dynamic VOLP/VOLV limits reduce ground bounce and improve signal integrity on shared bus lines. |
| GTO™ output control | Gradual turn-on/turn-off waveform shaping lowers di/dt-induced EMI during output transitions. |
| Split ground bus | Separates return paths for two output groups (O0–O3 vs. O4–O7), minimizing inter-group noise coupling. |
| Simultaneous switching immunity | Tested and guaranteed under worst-case 7-of-8 outputs switching at 1 MHz - critical for memory address buses. |
| Enhanced latch-up immunity | Withstands ±300 mA transient current - improves reliability in noisy industrial environments. |
Applications
| Memory Address Buffering | System Clock Distribution |
|---|---|
|
Use Scenario: Driving 16-bit address bus from microcontroller to SRAM/ROM in embedded control systems. IC Role / Device Role / Timing Role: Non-inverting buffer with independent OE control isolates address latching and reduces capacitive loading on MCU pins. Use Value: Guaranteed ≤1.0 ns output skew ensures setup/hold timing compliance across all address bits at 20 MHz operation. |
Use Scenario: Distributing a single system clock to multiple peripheral ICs (UART, SPI, ADC) on a shared PCB layer. IC Role / Device Role / Timing Role: Low-skew, low-noise line driver that maintains clean edge integrity without adding jitter. Use Value: Quiet Series™ dynamic threshold control prevents clock pulse distortion caused by simultaneous switching noise. |
| ISA Bus Transceiver Interface | Legacy Peripheral Expansion |
|
Use Scenario: Bidirectional data buffering between ISA bus and FPGA-based coprocessor in industrial PC add-in cards. IC Role / Device Role / Timing Role: 3-STATE-enabled octal driver/receiver supporting bus arbitration via OE1/OE2 control signals. Use Value: ±24 mA drive strength meets ISA specification for active-low data strobes and address latch enable signals. |
Use Scenario: Interfacing legacy parallel port peripherals (printers, scanners) to modern microcontroller-based controllers. IC Role / Device Role / Timing Role: Level-shifting and fan-out buffer for unidirectional control signals (STROBE, ACK, BUSY). Use Value: PDIP-20 package enables through-hole prototyping and field-replaceable upgrades in serviceable equipment. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal 3-STATE buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 74ACT244PC | No Quiet Series™ noise suppression; higher VOLP (up to 2.0 V), no GTO™ or split ground bus. | Lacks guaranteed dynamic threshold performance; unsuitable where SSN must be minimized. | Select only if cost sensitivity outweighs noise requirements and board layout allows extra filtering. |
| SN74ACT244N | Identical AC/ACT logic family, same pinout, but TI implementation lacks Quiet Series™ specifications and GTO™. | No documented simultaneous switching noise limits or dynamic VIHD/VILD guarantees. | Acceptable for general-purpose buffering where noise margins exceed 1.0 V; verify layout-dependent SSN empirically. |
Compared with 74ACTQ244PC, both alternatives offer identical pinout and basic functionality but omit Fairchild's Quiet Series™ enhancements - resulting in higher ground bounce, reduced dynamic noise margin, and no guaranteed skew or threshold stability under heavy bus loading.
Availability
74ACTQ244PC is available at Aetrix Electronics and suitable for memory address buffering, clock distribution, ISA bus interfacing, and legacy peripheral expansion requiring stable component supply and long-term industrial availability.
Supply support for 74ACTQ244PC 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, acquired by ON Semiconductor in 2016; its legacy logic families remain widely supported.
The 74ACTQ244PC belongs to the Quiet Series™ ACTQ logic family, engineered specifically for high-density digital systems where simultaneous switching noise and timing skew compromise bus reliability.
FAQ
What is the operating voltage range for the 74ACTQ244PC?
The 74ACTQ244PC operates strictly within 4.5 V to 5.5 V. It is not characterized or guaranteed for 3.3 V operation - unlike ACQ variants - and attempting to run it below 4.5 V may result in undefined logic thresholds, increased propagation delay, or failure to meet VOH/VOL specifications. Always use a regulated 5 V supply with proper decoupling.
Does the 74ACTQ244PC support true bidirectional data flow?
No, the 74ACTQ244PC is a unidirectional octal buffer with non-inverting inputs and outputs. It does not contain internal direction control or bus transceiver logic. For bidirectional applications, external OE control and separate transmit/receive paths must be implemented - the device functions only as a driver or receiver depending on OE state and system wiring.
How does the Quiet Series™ technology in the 74ACTQ244PC reduce noise?
The 74ACTQ244PC reduces noise via three integrated mechanisms: GTO™ (Gradual Turn-On) output control to limit di/dt, a split ground bus separating output groups to minimize return-path coupling, and undershoot correction circuitry that actively clamps negative voltage excursions. These features collectively suppress simultaneous switching noise (SSN) measured as VOLP and VOLV under worst-case 7-output switching conditions.
Can the 74ACTQ244PC replace a standard 74ACT244PC in an existing design?
Yes, the 74ACTQ244PC is pin-compatible and functionally identical to the 74ACT244PC, with identical DC/AC timing specs and logic behavior. However, substituting it introduces Quiet Series™ benefits - lower SSN, improved dynamic thresholds, and guaranteed skew - without requiring PCB changes. No firmware or timing adjustments are needed.
What is the maximum capacitive load the 74ACTQ244PC can drive reliably?
The 74ACTQ244PC is characterized up to 50 pF load capacitance per output, with guaranteed 7.0 ns max propagation delay and ≤0.44 V VOL at 24 mA sink current. Driving >50 pF increases delay nonlinearly and may degrade noise margins; for heavier loads, consider adding series termination or using a dedicated bus driver with higher drive strength.
74ACTQ244PC Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74ACTQ
- Package/Case:
- 20-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Logic Type:
- Buffer, Non-Inverting
- Number of Elements:
- 2
- Number of Bits per Element:
- 4
- 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
74ACTQ244PC FAQ
1.How can I place an order for 74ACTQ244PC through Aetrix?
Please submit a Request for Quotation (RFQ) for 74ACTQ244PC 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 74ACTQ244PC reliable?
The price and inventory of 74ACTQ244PC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74ACTQ244PC is usually 5 days.
3.What payment methods are accepted for 74ACTQ244PC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74ACTQ244PC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74ACTQ244PC?
74ACTQ244PC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74ACTQ244PC 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 74ACTQ244PC?
For technical support, including 74ACTQ244PC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74ACTQ244PC requirements.
6.How does Aetrix verify that 74ACTQ244PC is sourced from the original manufacturer or authorized distributors?
All 74ACTQ244PC 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 74ACTQ244PC meets industry standards.
7.What is the process for return or replacement of 74ACTQ244PC?
All 74ACTQ244PC units undergo pre-shipment inspection (PSI). If there is an issue with 74ACTQ244PC, 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 74ACTQ244PC part is unused and in its original packaging.
Return procedure for 74ACTQ244PC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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