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onsemi 74AC244SJ
- Part No.:
- 74AC244SJ
- Manufacturer:
- onsemi
- Package:
- 20-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
74AC244SJ.pdf
- Description:
- IC BUFF NON-INVERT 6V 20SOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,114
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Product details
Overview
74AC244SJ from ON Semiconductor is an octal non-inverting buffer/line driver with 3-STATE outputs, designed for memory address driving, clock distribution, and bus-oriented transmitter/receiver applications. It operates across 2.0V–6.0V VCC, delivers ±24mA output drive, supports −40°C to +85°C operation, and features low ICC (4.0µA typical) and low IOZ (±0.25µA typical) for power-sensitive digital systems.
For engineers reviewing the 74AC244SJ datasheet, pinout, applications, or equivalent options, this device is selected for high-density bus interfacing where low static current, TTL-compatible AC logic levels, and fast enable/disable timing (tPZH/tPHZ ≤ 10.5ns at 5V) are critical in industrial control and legacy system upgrades.
Technical Context
The 74AC244SJ implements dual 4-bit non-inverting buffers with independent 3-STATE enable controls (OE1 on pins 12/14/16/18; OE2 on pins 3/5/7/9), allowing selective activation of two groups of four outputs. Its AC logic family ensures CMOS-level input thresholds (VIH = 2.1V min @ 3V, 3.15V min @ 4.5V) and rail-to-rail output swing (VOH ≥ 2.9V @ 3V, VOL ≤ 0.1V).
It uses standard CMOS process technology with EIAJ TYPE II SOP-20 (M20D) packaging, supporting JEDEC-compliant PCB layout. Propagation delay is specified at 5.0–7.0ns (tPLH/tPHL @ 5V, CL = 50pF), and output enable/disable times are tightly controlled (tPZH/tPLZ ≤ 10.5ns, tPHZ/tPLZ ≤ 10.5ns), enabling reliable timing in synchronous bus architectures.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 2.0V to 6.0V - Supports mixed-voltage system interfacing (3.3V and 5V logic domains) |
| Output Drive | ±24mA - Sufficient to directly drive 50Ω transmission lines or multiple TTL loads without external buffering |
| tPLH / tPHL | 5.0ns typical @ 5V - Enables >100MHz bus operation with margin for setup/hold timing |
| tPZH / tPHZ | 7.0ns typical @ 5V - Allows rapid bus arbitration and dynamic output control in shared-data-path designs |
| ICC (Quiescent) | 4.0µA typical @ 5.5V - Minimizes standby power in always-on control subsystems |
| IOZ (3-STATE Leakage) | ±0.25µA typical @ 5.5V - Prevents signal corruption when outputs are disabled on loaded buses |
| Operating Temp | −40°C to +85°C - Qualified for industrial-grade embedded applications without derating |
Pinout & Package
EIAJ TYPE II 20-pin Small Outline Package (SOP), 5.3mm body width, gull-wing leads, JEDEC-compliant footprint (M20D). RoHS-compliant, lead-free per J-STD-020B.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 4, 6, 8, 10, 11, 13 | Inputs (I0–I7) | CMOS-compatible data inputs; accept 30%–70% VCC edge rates ≥125mV/ns for reliable switching |
| 12, 14, 16, 18 | OE1 (Group 1 Enable) | Active-low enable for outputs O0–O3; ties to common control line for half-bus gating |
| 3, 5, 7, 9 | OE2 (Group 2 Enable) | Active-low enable for outputs O4–O7; enables independent control of second quad group |
| 15, 17, 19, 20, 1, 2, 4, 6 | Outputs (O0–O7) | 3-STATE CMOS outputs; high-impedance state (Z) asserted when respective OE is HIGH |
| 10 | VCC | Positive supply pin; bypassing with 0.1µF ceramic capacitor near pin required for noise immunity |
| 20 | GND | Ground reference; must be low-inductance connection to minimize ground bounce during switching |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent 4-bit enables | OE1 and OE2 allow partitioned bus control - e.g., address vs. data lanes - reducing control logic complexity |
| Low ICC and IOZ | Reduces total system quiescent current by 50% vs. older TTL buffers, critical for battery-backed or energy-harvested controllers |
| ±24mA output sink/source | Eliminates need for external bus transceivers in medium-fanout applications (e.g., driving 10–15 TTL inputs) |
| AC logic voltage compatibility | Operates reliably from 2.0V to 6.0V - supports direct interface with both 3.3V microcontrollers and 5V legacy peripherals |
| Fast 3-STATE switching | tPZH/tPHZ ≤ 10.5ns ensures minimal bus contention window during direction or channel switching |
Applications
| Memory Address Buffering | Industrial Bus Transceiver |
|---|---|
|
Use Scenario: Driving 16-bit address bus from a microcontroller to multiple parallel EEPROM or SRAM devices. IC Role / Device Role: Non-inverting octal buffer isolating MCU address pins from capacitive bus load while enabling/disabling segments via OE1/OE2. Use Value: Prevents address skew and timing violations; ±24mA drive sustains signal integrity across 10cm PCB traces loaded with 50pF per device. |
Use Scenario: Bidirectional data path conditioning between PLC CPU and field I/O modules over 24V-tolerant backplane. IC Role / Device Role: Unidirectional line driver translating 3.3V/5V logic to robust bus signaling; OE controls direction handshake timing. Use Value: Fast enable/disable (≤10.5ns) eliminates bus turnaround dead time; low IOZ prevents leakage-induced false reads during idle cycles. |
| Legacy System Upgrade | Test Equipment Signal Conditioning |
|
Use Scenario: Replacing obsolete 74LS244 in aging instrumentation chassis requiring lower power and higher speed. IC Role / Device Role: Pin-compatible drop-in replacement with identical SOP-20 footprint and logic function, but improved AC performance. Use Value: Reduces board-level power by >70% (vs. LS) while cutting propagation delay by 60%, extending system timing margin without redesign. |
Use Scenario: Routing and buffering multiple DUT signals (clock, trigger, data) in automated test fixtures with tight skew budgets. IC Role / Device Role: Low-skew octal buffer distributing synchronized signals across fixture wiring harnesses with matched trace lengths. Use Value: Matched tPLH/tPHL (±0.5ns typical) and low CIN (4.5pF) preserve signal edge fidelity and minimize inter-channel skew below 100ps. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 74ACT244SJ | TTL-compatible inputs (VIH = 2.0V min @ 5V); otherwise identical AC specs and pinout | Better suited for mixed-logic systems with legacy TTL sources; requires no level-shifting | Select when driving from 74LS/74F sources; same SOP-20 package and thermal profile |
| SN74LVC244APWR | Lower VCC range (1.65V–3.6V); 32mA drive; 3.3V-only operation | Optimized for modern low-voltage SoC interfaces; not 5V-tolerant | Choose for new 3.3V-only designs requiring higher drive and smaller TSSOP-20 footprint |
Compared with 74AC244SJ, 74ACT244SJ offers TTL input compatibility at identical speed and drive, while SN74LVC244APWR provides higher drive and lower voltage operation but sacrifices 5V tolerance and requires PCB layout change.
Availability
74AC244SJ is available at Aetrix Electronics and suitable for industrial control systems, legacy equipment refurbishment, and test instrumentation requiring stable component supply, long-lifecycle support, and verified second-source alternatives.
Supply support for 74AC244SJ 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 (formerly Fairchild Semiconductor) is a global supplier of high-performance silicon solutions for automotive, industrial, cloud computing, and IoT applications, with leadership in analog, power management, and logic ICs.
The 74AC244SJ belongs to ON Semiconductor's legacy AC logic family, engineered for high-speed, low-power digital interfacing in industrial and computing infrastructure where reliability and long-term availability are essential.
FAQ
What is the maximum operating voltage for the 74AC244SJ?
The 74AC244SJ supports a recommended VCC range of 2.0V to 6.0V. Absolute maximum rating is +7.0V, but operation above 6.0V violates specification limits and risks parametric failure or reduced reliability. For sustained use, maintain VCC within 2.0V–6.0V per the Recommended Operating Conditions table in the datasheet.
Does the 74AC244SJ support 3.3V logic levels?
Yes, the 74AC244SJ fully supports 3.3V operation: VIH is guaranteed ≥2.1V at VCC = 3.0V, and VOH reaches ≥2.9V under 50µA load. Its AC logic family ensures clean switching and rail-aligned outputs at 3.3V, making it suitable for interfacing with modern microcontrollers without level shifters.
Is the 74AC244SJ pin-compatible with the 74LS244?
Yes - the 74AC244SJ uses the same 20-pin SOP (EIAJ TYPE II) package and identical pinout as the 74LS244, including I0–I7, O0–O7, OE1/OE2, VCC, and GND assignments. This allows direct replacement in existing layouts, though design review of timing margins and power delivery is recommended due to higher speed and lower drive impedance.
What is the thermal resistance (θJA) of the 74AC244SJ in its SOP-20 package?
The 74AC244SJ in M20D (EIAJ TYPE II SOP-20) package has a typical junction-to-ambient thermal resistance (θJA) of 120°C/W under standard JEDEC 2-layer board conditions. Actual θJA depends on PCB copper area and airflow; for continuous 24mA per output, junction temperature remains within 140°C limit up to +85°C ambient with minimal copper pour.
Can the 74AC244SJ drive a 50Ω transmission line directly?
Yes - with ±24mA output capability and VOH/VOL specified down to 2.4V/0.5V at 24mA (VCC = 5.5V), the 74AC244SJ can terminate and drive short 50Ω lines (≤15cm) in unterminated configurations. For longer runs or strict signal integrity, external series termination is recommended to suppress reflections.
74AC244SJ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74AC
- Package/Case:
- 20-SOIC (0.209", 5.30mm Width)
- 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:
- 2V ~ 6V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOP
74AC244SJ FAQ
1.How can I place an order for 74AC244SJ through Aetrix?
Please submit a Request for Quotation (RFQ) for 74AC244SJ 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 74AC244SJ reliable?
The price and inventory of 74AC244SJ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74AC244SJ is usually 5 days.
3.What payment methods are accepted for 74AC244SJ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74AC244SJ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74AC244SJ?
74AC244SJ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74AC244SJ 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 74AC244SJ?
For technical support, including 74AC244SJ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74AC244SJ requirements.
6.How does Aetrix verify that 74AC244SJ is sourced from the original manufacturer or authorized distributors?
All 74AC244SJ 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 74AC244SJ meets industry standards.
7.What is the process for return or replacement of 74AC244SJ?
All 74AC244SJ units undergo pre-shipment inspection (PSI). If there is an issue with 74AC244SJ, 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 74AC244SJ part is unused and in its original packaging.
Return procedure for 74AC244SJ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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