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Texas Instruments SN74HCT244NSR
- Part No.:
- SN74HCT244NSR
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
SN74HCT244NSR.pdf
- Description:
- IC BUFFER NON-INVERT 5.5V 20SO
- Quantity:
- Payment:
- Shipping:
Inventory:2,287
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Product details
Overview
SN74HCT244NSR from Texas Instruments is an octal non-inverting 3-state buffer/line driver IC operating at 4.5–5.5 V, delivering ±6 mA output drive per channel, 13 ns typical propagation delay (at 5.5 V, 50 pF), and high-current capability to drive up to 15 LSTTL loads - used for bus interfacing, memory address buffering, and I/O expansion in industrial control and telecom infrastructure.
For engineers reviewing the SN74HCT244NSR datasheet, SN74HCT244NSR pinout, SN74HCT244NSR application, or SN74HCT244NSR equivalent, key selection criteria include 3-state output control timing (enable/disable), TTL-compatible input thresholds, low quiescent current (≤80 µA), and SOP-20 package compatibility with legacy 5 V logic systems.
Technical Context
The SN74HCT244NSR implements two independent 4-bit buffer sections, each with dedicated active-low output-enable (OE) inputs (1OE and 2OE). When OE is low, data passes non-inverted from A inputs to Y outputs; when OE is high, all eight outputs enter high-impedance state - enabling bidirectional bus sharing without contention.
It uses HCMOS technology with TTL-voltage-compatible inputs (VIH = 2 V min, VIL = 0.8 V max at VCC = 4.5–5.5 V), operates across –40°C to +85°C, and features low input current (≤1 µA) and low power consumption (ICC ≤ 80 µA), making it suitable for noise-immune, low-static-power 5 V digital systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply voltage | 4.5 V to 5.5 V - ensures compatibility with standard 5 V TTL/CMOS rails and stable operation under ±5% supply variation. |
| Propagation delay (tpd) | 13 ns typical at VCC = 5.5 V, CL = 50 pF - enables reliable timing in high-speed 5 V bus applications up to ~30 MHz clock-equivalent rates. |
| Output drive | ±6 mA per output at VCC = 5 V - sufficient to directly drive 15 LSTTL loads or terminate short PCB traces without external buffers. |
| Input compatibility | TTL-voltage compatible (VIH ≥ 2 V, VIL ≤ 0.8 V) - allows seamless interfacing with legacy 5 V TTL logic without level-shifting. |
| Quiescent current (ICC) | ≤80 µA maximum - minimizes standby power in always-on industrial control modules and remote I/O nodes. |
| 3-state enable/disable time | ten = 19 ns, tdis = 18 ns typical at VCC = 5.5 V, CL = 50 pF - supports fast bus arbitration and dynamic peripheral multiplexing. |
| Operating temperature | –40°C to +85°C - qualified for commercial and extended-temperature industrial environments including network switches and motor drivers. |
Pinout & Package
SOP-20 (NS) package: 12.6 mm × 7.8 mm body size, 20-pin surface-mount, RoHS-compliant, moisture sensitivity level 1 (260°C reflow).
| 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); must be pulled low to enable outputs. |
| 2, 4, 6, 8 | 1A1–1A4 | Group 1 input signals - routed directly to corresponding Y outputs when 1OE = low. |
| 3, 5, 7, 9 | 1Y1–1Y4 | Group 1 buffered non-inverting outputs - high-impedance when 1OE = high. |
| 11, 13, 15, 17 | 2A1–2A4 | Group 2 input signals - independent of Group 1, controlled by 2OE. |
| 12, 14, 16, 18 | 2Y1–2Y4 | Group 2 buffered non-inverting outputs - isolated bus drivers for dual-channel memory or peripheral addressing. |
| 10 | GND | Ground reference for all logic and output stages - requires low-inductance connection to minimize switching noise. |
| 20 | VCC | Positive supply (4.5–5.5 V) - requires local 0.1 µF ceramic bypass capacitor placed adjacent to pin. |
Key Features
| Feature | Design Value |
|---|---|
| Octal 3-state buffering | Two independent 4-bit groups with separate OE pins allow selective bus isolation - critical for multi-master memory or I/O subsystems. |
| TTL-compatible inputs | VIH ≥ 2 V and VIL ≤ 0.8 V at 5 V supply eliminate need for external level translators when interfacing with legacy TTL peripherals. |
| High-output drive | ±6 mA per output supports direct fanout to 15 LSTTL loads - reduces component count in LED display column drivers and address buffers. |
| Low static power | ICC ≤ 80 µA ensures minimal self-heating and battery-friendly operation in always-on industrial monitoring nodes. |
| Fast enable/disable control | ten/tdis ≤ 19 ns enables rapid bus turnaround in time-critical applications like PCIe sideband or SPI multiplexer control. |
Applications
| Memory Address Buffering | LED Display Column Driving |
|---|---|
Use Scenario: Buffering 8-bit address lines between microcontroller and parallel SRAM or EPROM in embedded instrumentation. IC Role / Device Role / Timing Role: Non-inverting 3-state buffer isolating address bus during DMA cycles or peripheral access. Use Value: Prevents bus contention and signal degradation over >10 cm PCB traces while maintaining <13 ns timing margin at 5 V. |
Use Scenario: Driving common-anode LED matrix columns in industrial HMIs with 5 V logic supply. IC Role / Device Role / Timing Role: High-current sink driver enabling simultaneous activation of up to 15 LEDs per segment. Use Value: Eliminates need for discrete transistor arrays - simplifies layout and reduces BOM cost in 8×8 or 16×8 displays. |
| Network Switch Control Plane | Industrial I/O Expander Interface |
Use Scenario: Isolating configuration registers and status lines between management MCU and PHY controllers in 10/100 Mbps Ethernet switches. IC Role / Device Role / Timing Role: Bidirectional bus interface with independent OE control for read/write arbitration. Use Value: Enables glitch-free register access during hot-swap events and supports 25 ns setup/hold margins per IEEE 802.3. |
Use Scenario: Extending GPIO count of PLC main controller to manage relay banks, sensor inputs, and indicator LEDs. IC Role / Device Role / Timing Role: Level-translating buffer between 3.3 V MCU and 5 V industrial field-side logic. Use Value: TTL-compatible inputs accept 3.3 V logic highs directly; ±6 mA drive sustains 5 V signaling integrity over 15 cm ribbon cables. |
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 |
|---|---|---|---|
| SN74HCT244DWR | SOIC-20 (DW) package; identical electrical specs but larger 12.8 mm × 10.3 mm footprint and higher thermal resistance (RθJA = 109.1°C/W vs NS's 113.4°C/W). | Preferred where manual soldering or through-hole prototyping is required; less suitable for high-density SMT layouts. | Select DWR only if board space permits larger SOIC or legacy assembly processes mandate DW footprint. |
| SN74LVTH244APWRE4 | Lower VCC range (2.7–3.6 V), LVTH logic family; 3.3 V optimized with 24 mA drive, but incompatible with 5 V systems without level shifters. | Designed for modern low-voltage embedded systems - not drop-in replaceable in 5 V designs due to supply and voltage threshold mismatch. | Choose LVTH variant only when migrating to 3.3 V architecture; avoid in mixed 5 V legacy systems. |
Compared with SN74HCT244DWR and SN74LVTH244APWRE4, the SN74HCT244NSR offers optimal balance of 5 V compatibility, SOP-20 compactness (12.6 mm × 7.8 mm), and proven industrial temperature support - making it the preferred choice for cost-sensitive, space-constrained 5 V bus interface designs.
Availability
SN74HCT244NSR is available at Aetrix Electronics and suitable for industrial I/O expansion, LED display driving, and memory address buffering requiring stable component supply across automotive-grade temperature ranges and long-lifecycle production programs.
Supply support for SN74HCT244NSR 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 decades of heritage in high-reliability industrial and automotive components.
The SN74HCT244NSR belongs to TI's HCT logic family - designed specifically for 5 V TTL-compatible bus interfacing, memory address buffering, and 3-state I/O expansion in industrial control, telecom, and instrumentation systems.
FAQ
What is the maximum operating temperature for SN74HCT244NSR?
The SN74HCT244NSR is rated for operation from –40°C to +85°C. This extended commercial temperature range supports deployment in industrial environments such as factory automation controllers and outdoor telecom cabinets where ambient temperatures exceed standard commercial limits. The device maintains full electrical specifications across this range, including propagation delay and output drive capability.
Does SN74HCT244NSR require external pull-up resistors on its OE pins?
SN74HCT244NSR OE pins are active-low and do not require external pull-ups for basic functionality - they can be driven directly by MCU GPIOs or logic gates. However, during power-up/power-down sequencing, tying OE to VCC via a pull-up resistor (e.g., 10 kΩ) ensures outputs remain in high-impedance state until firmware initializes, preventing bus contention. TI recommends this for robust system-level reliability.
Can SN74HCT244NSR interface directly with 3.3 V microcontrollers?
Yes - SN74HCT244NSR inputs are TTL-voltage compatible: VIH(min) = 2.0 V and VIL(max) = 0.8 V at VCC = 4.5–5.5 V. A 3.3 V MCU's logic-high output (~3.3 V) exceeds the 2.0 V VIH threshold, and its logic-low (~0 V) is well below 0.8 V VIL, ensuring reliable recognition without level shifting. Outputs remain 5 V, so downstream 5 V logic is fully supported.
What is the recommended bypass capacitor for SN74HCT244NSR?
Texas Instruments specifies a 0.1 µF ceramic capacitor placed as close as possible to the VCC pin (pin 20) and GND (pin 10) of the SN74HCT244NSR. This minimizes high-frequency supply noise induced by fast output transitions. For boards with multiple SN74HCT244NSR devices, one 0.1 µF cap per device is required; bulk capacitance (e.g., 4.7 µF tantalum) may be added at the board-level power entry point.
How many LSTTL loads can SN74HCT244NSR drive per output?
SN74HCT244NSR can drive up to 15 LSTTL loads per output, as confirmed in TI's official datasheet. This is enabled by its ±6 mA output current capability at VCC = 5 V, which matches the aggregate input current demand (≈400 µA per LSTTL input × 15 = 6 mA) while maintaining valid VOH/VOL levels. This eliminates need for additional buffer stages in dense bus architectures.
SN74HCT244NSR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HCT
- Package/Case:
- 20-SOIC (0.209", 5.30mm Width)
- Packaging:
- Tape & Reel (TR)
- 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:
- Surface Mount
- Supplier Device Package:
- 20-SO
SN74HCT244NSR FAQ
1.How can I place an order for SN74HCT244NSR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74HCT244NSR 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 SN74HCT244NSR reliable?
The price and inventory of SN74HCT244NSR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74HCT244NSR is usually 5 days.
3.What payment methods are accepted for SN74HCT244NSR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74HCT244NSR transactions.
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4.How is shipping managed for SN74HCT244NSR?
SN74HCT244NSR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74HCT244NSR 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 SN74HCT244NSR?
For technical support, including SN74HCT244NSR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74HCT244NSR requirements.
6.How does Aetrix verify that SN74HCT244NSR is sourced from the original manufacturer or authorized distributors?
All SN74HCT244NSR 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 SN74HCT244NSR meets industry standards.
7.What is the process for return or replacement of SN74HCT244NSR?
All SN74HCT244NSR units undergo pre-shipment inspection (PSI). If there is an issue with SN74HCT244NSR, 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 SN74HCT244NSR part is unused and in its original packaging.
Return procedure for SN74HCT244NSR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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