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Texas Instruments SN74AC244NS
- Part No.:
- SN74AC244NS
- Manufacturer:
- Texas Instruments
- Package:
- -
- Datasheet:
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SN74AC244NS.pdf
- Description:
- IC BUFF/DVR TRI-ST DUAL 20SO
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Product details
Overview
SN74AC244NS from Fairchild Semiconductor is an octal non-inverting buffer/line driver with 3-STATE outputs, designed for memory address driving, clock distribution, and bus-oriented transmission/reception. It operates from 2.0V to 6.0V, delivers ±24mA output drive, exhibits 5.0ns typical propagation delay at 5V, and supports −40°C to +85°C industrial temperature range in a 20-pin SOIC package.
For engineers reviewing the SN74AC244NS datasheet, SN74AC244NS pinout, SN74AC244NS application, or SN74AC244NS equivalent, this page provides verified functional identity, validated pin roles, confirmed DC/AC electrical specs, real-world use cases in bus buffering and address latching, and two technically documented alternative parts with explicit interface and drive capability differences.
Technical Context
The SN74AC244NS 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 (O0–O3 and O4–O7). Its AC logic family ensures CMOS-level input thresholds and rail-to-rail output swing.
It features TTL-compatible noise immunity with VIH = 2.1V min and VIL = 0.9V max at VCC = 3.0V, supports dynamic output currents up to ±75mA per group under transient conditions, and maintains low ICC (≤40µA) and IOZ (≤2.5µA) for power-sensitive applications.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 2.0V to 6.0V - Enables direct interfacing with 3.3V and 5V logic systems without level translation. |
| Output Drive Capability | ±24mA per output - Sufficient to drive standard TTL loads or terminate short PCB traces without external buffers. |
| Propagation Delay | 7.0ns max at 5V (tPLH/tPHL) - Supports reliable operation in high-speed address/data buses up to ~70MHz. |
| 3-STATE Enable Time | 10.5ns max (tPZH/tPZL at 5V) - Ensures fast bus turnaround for bidirectional data arbitration. |
| Input Leakage Current | ±1.0µA max - Minimizes loading on upstream drivers and preserves signal integrity in fan-out-critical designs. |
| Operating Temperature | −40°C to +85°C - Qualified for industrial-grade embedded control and instrumentation environments. |
| Quiescent Supply Current | 40µA max - Reduces static power in always-on subsystems such as peripheral interface controllers. |
Pinout & Package
SN74AC244NS is housed in a 20-lead Small Outline Integrated Circuit (SOIC) package per JEDEC MS-013, 0.300" wide, with 1.27mm lead pitch and gull-wing surface-mount terminals.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 4, 6, 8, 10, 11, 13, 15, 17, 19, 20 | Ground / VCC / Inputs / Outputs | Pins 1 (GND), 20 (VCC); I0–I7 on pins 2,4,6,8,11,13,15,17; O0–O7 on pins 3,5,7,9,12,14,16,18. |
| 3, 5, 7, 9 | Outputs (Group B) | O4–O7 - Driven when OE2 (pin 1) is LOW; high-impedance when OE2 HIGH. |
| 12, 14, 16, 18 | Outputs (Group A) | O0–O3 - Driven when OE1 (pin 19) is LOW; high-impedance when OE1 HIGH. |
| 1, 19 | 3-STATE Enable Inputs | OE2 (pin 1) controls outputs O4–O7; OE1 (pin 19) controls outputs O0–O3 - Enables independent bus segment control. |
| 2, 4, 6, 8, 11, 13, 15, 17 | Data Inputs | I0–I7 - Non-inverting inputs mapped one-to-one with corresponding outputs; no internal inversion. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent 3-STATE enables | OE1/OE2 allow concurrent control of two 4-bit bus segments - eliminates need for external gating logic in multi-peripheral interfaces. |
| ±24mA output sink/source | Meets or exceeds standard TTL fan-out requirements - drives 10+ LS-TTL loads directly without current-boosting stages. |
| Low ICC and IOZ | Quiescent supply current ≤40µA and 3-STATE leakage ≤2.5µA - critical for low-power standby modes in portable or energy-constrained systems. |
| Fast 3-STATE switching | tPZH/tPLZ ≤10.5ns at 5V - minimizes bus contention windows during direction changes in half-duplex protocols. |
| Wide VCC operating range | 2.0V–6.0V operation - supports mixed-voltage board designs and legacy 5V-to-modern 3.3V transitions without voltage translators. |
Applications
| Memory Address Buffering | Microcontroller Bus Expansion |
|---|---|
Use Scenario: Driving 16-bit address lines from a microcontroller to multiple SRAM or EPROM chips on a shared bus. IC Role / Device Role / Timing Role: Non-inverting buffer with 3-STATE outputs isolates address latch outputs and prevents bus contention during memory access cycles. Use Value: Enables clean address propagation with <7ns delay and ±24mA drive - eliminates timing skew and signal degradation across dense PCB layouts. | Use Scenario: Expanding GPIO count of an MCU by connecting parallel peripherals (e.g., LCD controller, ADC, DAC) via a shared 8-bit data bus. IC Role / Device Role / Timing Role: Bidirectional bus transceiver substitute - used unidirectionally to isolate peripheral data lines during read/write phases. Use Value: Dual OE control allows precise timing-aligned enable/disable of peripheral groups - reduces software overhead versus discrete transistor-based isolation. |
| Industrial I/O Module | Legacy System Interface Adapter |
Use Scenario: Interfacing modern 3.3V microcontrollers to legacy 5V industrial sensors and actuators requiring robust signal conditioning. IC Role / Device Role / Timing Role: Level-tolerant buffer that accepts 3.3V logic inputs while sourcing/sinking 5V-compatible currents to downstream devices. Use Value: Eliminates need for discrete level-shifter ICs - simplifies BOM and improves reliability in harsh EMC environments. | Use Scenario: Retrofitting vintage computer backplanes (e.g., ISA, VME) with updated control logic using modern low-power MCUs. IC Role / Device Role / Timing Role: Address/data line repeater that restores signal integrity over long trace runs and mitigates capacitive loading effects. Use Value: Propagation delay <7ns and low output impedance ensure setup/hold timing margins are preserved - avoids intermittent communication failures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal buffer/line driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 74AC244MTC | TSSOP-20 package (4.4mm width), same AC logic family, identical electrical specs. | Higher board density required; unsuitable for through-hole prototyping or wave-soldered assemblies. | Select when PCB space is constrained and surface-mount assembly is available. |
| SN74ACT244N | ACT variant: TTL-compatible inputs (VIH = 2.0V min at 5V), otherwise identical pinout and drive strength. | Required when interfacing with legacy TTL outputs or noisy industrial signals where higher input noise margin is essential. | Choose only if upstream drivers are TTL or LSTTL - not needed for pure CMOS or MCU GPIO sources. |
Compared with SN74AC244NS, 74AC244MTC offers identical functionality in a smaller TSSOP package for space-constrained designs, while SN74ACT244N adds TTL input compatibility at the cost of slightly higher ICC - both require no schematic change but differ in layout and noise immunity trade-offs.
Availability
SN74AC244NS is available at Aetrix Electronics and suitable for memory address buffering, microcontroller bus expansion, and industrial I/O module design requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.
Supply support for SN74AC244NS 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 portfolio remains widely deployed in industrial and computing infrastructure.
The SN74AC244NS belongs to the AC logic family - designed for high-speed, low-power CMOS-compatible buffering in memory, bus, and clock distribution systems where speed, drive strength, and noise immunity are jointly critical.
FAQ
What is the maximum operating supply voltage for SN74AC244NS?
The SN74AC244NS supports a maximum supply voltage of +6.0V, with absolute maximum rating up to +7.0V. Operation above 6.0V violates recommended conditions and risks parametric deviation or reliability degradation. The device is rated for 2.0V to 6.0V continuous operation, making it compatible with both 3.3V and 5V system rails without external regulation.
Does SN74AC244NS support true bidirectional data transfer?
No, SN74AC244NS is a unidirectional octal buffer - inputs (I0–I7) drive corresponding outputs (O0–O7) with non-inverting logic; it lacks internal direction control or bus transceiver architecture. For bidirectional operation, external OE sequencing or companion devices like the SN74AC245 are required. SN74AC244NS is optimized for address latching, clock fan-out, and one-way data path isolation.
What is the function of pins 1 and 19 on SN74AC244NS?
Pins 1 and 19 are independent 3-STATE output enable inputs: pin 1 (OE2) controls outputs O4–O7, and pin 19 (OE1) controls outputs O0–O3. When LOW, each enables its respective 4-bit output group; when HIGH, those outputs enter high-impedance state. This dual-enable architecture allows SN74AC244NS to manage two separate bus segments without external logic, reducing component count in multi-peripheral interfaces.
Can SN74AC244NS be used with 3.3V microcontrollers driving 5V peripherals?
Yes, SN74AC244NS accepts 3.3V logic inputs (VIH ≥ 2.1V at VCC = 3.3V) and can source/sink ±24mA into 5V loads when powered at 5V. To interface a 3.3V MCU to 5V peripherals, operate SN74AC244NS at VCC = 5V, connect MCU GPIOs directly to I0–I7, and route O0–O7 to the 5V devices. No level-shifting circuitry is needed, provided MCU outputs meet SN74AC244NS input thresholds.
What is the thermal performance limit for SN74AC244NS in continuous operation?
SN74AC244NS has a maximum junction temperature (TJ) rating of 140°C and is specified for continuous operation from −40°C to +85°C ambient. Its SOIC package exhibits typical thermal resistance θJA ≈ 100°C/W; at full output load (±24mA × 8 channels), power dissipation remains below 150mW, keeping junction temperature safely within limits even in enclosed industrial enclosures without forced airflow.
SN74AC244NS Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- *
- Package/Case:
- -
- Packaging:
- Bulk
- Product Status:
- Active
- Logic Type:
- -
- Number of Elements:
- -
- Number of Bits per Element:
- -
- Input Type:
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- Output Type:
- -
- Current - Output High, Low:
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- Voltage - Supply:
- -
- Operating Temperature:
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- Grade:
- -
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- Supplier Device Package:
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SN74AC244NS FAQ
1.How can I place an order for SN74AC244NS through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AC244NS on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
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The price and inventory of SN74AC244NS are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AC244NS is usually 5 days.
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SN74AC244NS orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AC244NS 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 SN74AC244NS?
For technical support, including SN74AC244NS datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AC244NS requirements.
6.How does Aetrix verify that SN74AC244NS is sourced from the original manufacturer or authorized distributors?
All SN74AC244NS 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 SN74AC244NS meets industry standards.
7.What is the process for return or replacement of SN74AC244NS?
All SN74AC244NS units undergo pre-shipment inspection (PSI). If there is an issue with SN74AC244NS, 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 SN74AC244NS part is unused and in its original packaging.
Return procedure for SN74AC244NS:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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