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Texas Instruments SN74HCT244N
- Part No.:
- SN74HCT244N
- Manufacturer:
- Texas Instruments
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
SN74HCT244N.pdf
- Description:
- IC BUF NON-INVERT 5.5V 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:3,539
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Product details
Overview
SN74HCT244N from Texas Instruments is an octal non-inverting 3-state buffer/line driver in a 20-pin PDIP package, operating at 4.5–5.5 V, delivering ±6 mA output drive per channel with 13 ns typical propagation delay and 80 µA maximum ICC. It serves as a bus interface and memory address driver in industrial control backplanes and legacy 5V logic systems.
For engineers reviewing the SN74HCT244N datasheet, SN74HCT244N pinout, SN74HCT244N application, or SN74HCT244N equivalent, key selection criteria include TTL-compatible inputs, high-current 3-state outputs for bus contention management, thermal performance in through-hole mounting, and compatibility with legacy 5V LSTTL load driving (up to 15 loads).
Technical Context
The SN74HCT244N implements two independent 4-bit buffer sections, each with dedicated active-low output-enable (OE) control. Its CMOS HCT logic family ensures TTL voltage-level compatibility while maintaining low static power consumption.
Each buffer passes A-inputs to Y-outputs when OE is low; all eight outputs enter high-impedance state when OE is high. Input transition rates are specified up to 500 ns, and operation is guaranteed across –40°C to +85°C ambient temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - Ensures stable operation in standard 5V rail systems with ±10% tolerance. |
| Propagation Delay (tpd) | 13 ns typical at 5.5 V, CL = 50 pF - Enables reliable timing in 30+ MHz bus interfaces. |
| Output Drive | ±6 mA per output at 5 V - Sufficient to directly drive 15 LSTTL loads without external buffering. |
| Input Compatibility | TTL-voltage compatible (VIH = 2 V min, VIL = 0.8 V max) - Interoperates seamlessly with legacy 74LS and 74ALS logic families. |
| Quiescent Current | 80 µA maximum ICC - Supports low-power standby modes in always-on industrial controllers. |
| ESD Rating | ±2000 V HBM - Meets standard handling requirements for manual assembly and board-level rework. |
| Operating Temperature | –40°C to +85°C - Qualified for commercial and extended industrial environments. |
Pinout & Package
SN74HCT244N uses a 20-pin plastic dual in-line package (PDIP-N), body size 24.33 mm × 6.35 mm, with through-hole mounting and industry-standard 0.3-inch row spacing.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | 1OE, 2OE | Active-low output-enable controls for Group 1 (pins 2–9) and Group 2 (pins 11–18); asserted low enables respective Y outputs. |
| 2–5, 11–14 | 1A1–1A4, 2A1–2A4 | Non-inverting input terminals; accept TTL-compatible logic signals and pass directly to corresponding Y outputs when OE is active. |
| 3, 5, 7, 9, 12, 14, 16, 18 | 1Y1–1Y4, 2Y1–2Y4 | 3-state buffered outputs; driven high/low when OE is low, high-impedance when OE is high - enables shared bus arbitration. |
| 10 | GND | Ground reference for logic and power return; must be low-impedance connection to minimize noise coupling. |
| 20 | VCC | Positive supply terminal; requires local 0.1 µF ceramic bypass capacitor placed adjacent to pin for stable switching operation. |
Key Features
| Feature | Design Value |
|---|---|
| Octal 3-state buffering | Two independent 4-bit groups allow selective bus isolation - critical for multi-master memory or I/O expansion designs. |
| TTL-compatible inputs | Accepts standard 74LS logic thresholds without level-shifting, simplifying integration into mixed-logic systems. |
| High-output current | ±6 mA per output supports direct fanout to 15 LSTTL loads - eliminates need for external drivers in cost-sensitive applications. |
| Low quiescent power | 80 µA max ICC enables use in battery-backed or energy-constrained subsystems where standby leakage matters. |
| Robust ESD protection | ±2000 V HBM rating meets IPC-7351B handling requirements for manual PCB assembly and field repair. |
Applications
| Industrial Backplane Bus Interface | Legacy Microcontroller I/O Expansion |
|---|---|
|
Use Scenario: Isolating and driving address/data lines between a PLC CPU module and multiple I/O carrier boards over a 150 mm backplane trace. IC Role / Device Role / Timing Role: Bidirectional 3-state buffer that enables time-multiplexed access to shared memory-mapped peripherals while preventing bus contention. Use Value: ±6 mA drive strength maintains signal integrity across long traces; 13 ns tpd ensures setup/hold timing margins at 20 MHz clock rates. |
Use Scenario: Expanding GPIO count of an 8051-based motor controller to drive 8 discrete LED indicators and 4 opto-isolated relay drivers. IC Role / Device Role / Timing Role: Unidirectional non-inverting buffer translating MCU port pins to higher-current outputs with TTL-compatible input thresholds. Use Value: Direct LSTTL load driving eliminates discrete transistor stages; PDIP package allows hand-soldering during prototyping and field service. |
| LED Segment Driver Interface | Memory Address Register Buffer |
|
Use Scenario: Driving common-anode 7-segment displays in a panel-mounted HVAC controller using multiplexed digit scanning at 1 kHz. IC Role / Device Role / Timing Role: High-current sink driver for display segments, enabled per-digit via OE control synchronized with scan timing. Use Value: 6 mA per segment supports bright visibility under ambient light; 3-state capability prevents ghosting during digit transitions. |
Use Scenario: Buffering 16-bit address lines from a Z80 CPU to dual-port SRAM in a retro-computing development system. IC Role / Device Role / Timing Role: Low-skew, non-inverting address latch driver ensuring clean setup to RAM address inputs with minimal propagation delay variation. Use Value: 13 ns typical tpd and matched group delay (<2 ns skew between channels) preserve address validity windows at 4 MHz bus speeds. |
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 |
|---|---|---|---|
| SN74HCT244PW | TSSOP-20 package (6.5 mm × 6.4 mm), lead-free, MSL-1 rated - smaller footprint but surface-mount only. | Suitable for space-constrained PCBs; not hand-solderable or socket-compatible like SN74HCT244N. | Select when board area is limited and reflow assembly is available; avoid if through-hole prototyping or field replacement is required. |
| 74ACT244PC | Advanced CMOS (ACT) family: 4.5–5.5 V supply, 8 ns tpd, ±24 mA drive - faster and stronger, but higher ICC (40 mA max). | Better for high-speed buses (>33 MHz) or heavy capacitive loads; requires tighter power delivery and thermal management. | Choose when speed or drive strength outweighs power budget constraints; verify layout for reduced ringing due to faster edges. |
Compared with SN74HCT244PW and 74ACT244PC, the SN74HCT244N offers optimal balance of legacy compatibility, hand-solderability, and moderate speed/power for industrial control and retro-system upgrades - its PDIP package and 13 ns timing make it uniquely suited for through-hole designs requiring field serviceability and proven reliability.
Availability
SN74HCT244N is available at Aetrix Electronics and suitable for industrial backplanes, microcontroller I/O expansion, LED display interfaces, and memory address buffering requiring stable component supply and long-term obsolescence support.
Supply support for SN74HCT244N 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
Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and logic solutions, with over 90 years of innovation in industrial, automotive, and communications markets.
The SN74HCT244N belongs to TI's HCT logic family, designed specifically for TTL-compatible 5V systems requiring robust noise immunity, predictable timing, and seamless interoperability with legacy bipolar logic in industrial control and instrumentation.
FAQ
What is the maximum operating temperature range for the SN74HCT244N?
The SN74HCT244N is rated for operation from –40°C to +85°C ambient temperature. This range is validated per TI's production test conditions and supports deployment in commercial and extended industrial environments, including factory-floor controllers and outdoor telecom enclosures with passive thermal management.
Does the SN74HCT244N require pull-up resistors on its OE pins?
Yes - for predictable high-impedance behavior during power-up and power-down, TI recommends tying both 1OE and 2OE to VCC via pull-up resistors. The minimum resistance value depends on the current-sinking capability of the enabling source; typical values range from 4.7 kΩ to 10 kΩ for standard logic drivers.
Can the SN74HCT244N drive a 150 pF capacitive load reliably?
Yes - the SN74HCT244N specifies switching characteristics up to 150 pF load capacitance. At 5.5 V supply, its typical propagation delay remains ≤38 ns and output rise/fall times stay within 16 ns, ensuring signal integrity on moderately loaded PCB traces or unterminated stubs in backplane applications.
Is the SN74HCT244N RoHS compliant?
Yes - the SN74HCT244N is RoHS compliant with lead-free terminations (NIPDAU finish) and conforms to EU Directive 2011/65/EU. Its PDIP package contains no exempted leaded solder, and full compliance documentation is available in TI's official packaging addendum.
How does the SN74HCT244N differ from the SN74HC244 in practical use?
The SN74HCT244N features TTL-compatible input thresholds (VIH = 2 V min), making it interoperable with 74LS and other bipolar logic without level shifters. In contrast, the SN74HC244 uses CMOS thresholds (VIH ≈ 3.5 V), requiring careful voltage translation when interfacing with legacy 5V TTL systems - a key distinction in mixed-technology retro designs.
SN74HCT244N Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HCT
- Package/Case:
- 20-DIP (0.300", 7.62mm)
- Packaging:
- Bulk
- Product Status:
- Active
- 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:
- 6mA, 6mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 20-PDIP
SN74HCT244N FAQ
1.How can I place an order for SN74HCT244N through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74HCT244N 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 SN74HCT244N reliable?
The price and inventory of SN74HCT244N are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74HCT244N is usually 5 days.
3.What payment methods are accepted for SN74HCT244N?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74HCT244N transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74HCT244N?
SN74HCT244N orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74HCT244N 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 SN74HCT244N?
For technical support, including SN74HCT244N datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74HCT244N requirements.
6.How does Aetrix verify that SN74HCT244N is sourced from the original manufacturer or authorized distributors?
All SN74HCT244N 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 SN74HCT244N meets industry standards.
7.What is the process for return or replacement of SN74HCT244N?
All SN74HCT244N units undergo pre-shipment inspection (PSI). If there is an issue with SN74HCT244N, 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 SN74HCT244N part is unused and in its original packaging.
Return procedure for SN74HCT244N:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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