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Texas Instruments SN74LS244NE4
- Part No.:
- SN74LS244NE4
- Manufacturer:
- Texas Instruments
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
SN74LS244NE4.pdf
- Description:
- IC BUF NON-INVERT 5.25V 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:4,135
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Product details
Overview
SN74LS244NE4 from Texas Instruments is an octal non-inverting 3-state buffer/line driver in a 20-pin PDIP package, designed for memory address and bus line driving. It features two independent 4-bit channels (1A→1Y and 2A→2Y), 24 mA low-level output drive at 5 V, 18 ns maximum propagation delay, and hysteresis-enhanced noise immunity. It is used in legacy industrial control backplanes and memory subsystems requiring TTL-compatible buffering with bus isolation.
For engineers reviewing the SN74LS244NE4 datasheet, SN74LS244NE4 pinout, SN74LS244NE4 application, or SN74LS244NE4 equivalent, key selection criteria include 3-state enable timing (tPZH/tPLZ), DC input tolerance down to 2 V, PNP-input reduced bus loading, and compatibility with mixed 3.3-V/5-V logic interfaces in bus-hold or repeater configurations.
Technical Context
The SN74LS244NE4 implements dual 4-bit non-inverting buffers with active-low 3-state enable inputs (1G and 2G). Each channel passes A-side inputs to Y-side outputs when its G input is low; outputs enter high-impedance state when G is high. Inputs use PNP transistor structures to minimize DC loading on source buses.
Hysteresis (0.2–0.4 V) is built into all inputs to improve noise margins in electrically noisy environments. The device operates strictly at 5 V (4.75–5.25 V recommended), supports 24 mA sink per output, and delivers 2.4 V minimum VOH at –3 mA load - enabling direct interfacing with standard TTL loads without level-shifting.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.75–5.25 V - ensures stable TTL-compatible operation; outside this range risks VOH/VOL degradation or latch-up |
| Output Drive (IOL) | 24 mA per output - sufficient to drive 10 standard TTL loads or terminate 133-Ω transmission lines |
| Propagation Delay | 12–18 ns (tPLH/tPHL) - enables reliable operation up to ~30 MHz bus clocking in short-trace applications |
| Input Hysteresis | 0.2–0.4 V - increases effective noise margin by rejecting sub-threshold glitches on shared bus lines |
| 3-State Enable Time | tPZH = 15–23 ns, tPLZ = 10–20 ns - determines minimum bus turnaround interval in bidirectional data transfer |
| Input Compatibility | Tolerates 2 V min VIH - allows direct connection to 3.3-V CMOS outputs without external pull-ups or translators |
| Quiescent Current | 27–46 mA (all outputs active) - impacts thermal design in dense PCB layouts; disabled-state ICC = 32–54 mA |
Pinout & Package
SN74LS244NE4 uses a 20-pin plastic dual in-line package (PDIP-N), body size 24.33 mm × 6.35 mm, with through-hole mounting and 0.3-inch row spacing.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | 1G / 2G | Active-low output-enable controls for Channel 1 and Channel 2 - must be pulled high via resistor during power-up to prevent bus contention |
| 2, 4, 6, 8, 11, 13, 15, 17 | 1A1–1A4 / 2A1–2A4 | Non-inverting data inputs - PNP structure reduces DC loading on upstream drivers and improves fan-in |
| 3, 5, 7, 9, 12, 14, 16, 18 | 2Y4–2Y1 / 1Y4–1Y1 | Non-inverting 3-state outputs - drive bus lines directly; high-Z state isolates sections during data arbitration |
| 10 | GND | Signal reference ground - requires low-inductance connection to system ground plane to maintain noise margin |
| 20 | VCC | +5 V power supply - bypassing with 0.1 µF ceramic capacitor near pin essential for switching stability |
Key Features
| Feature | Design Value |
|---|---|
| PNP input structure | Reduces input DC loading to ≤0.2 mA per pin - minimizes voltage droop on shared address/data buses |
| Input hysteresis | 0.2–0.4 V threshold separation - rejects noise spikes <400 mV amplitude without external filtering |
| 3-state bus isolation | Independent 1G/2G enables bidirectional bus partitioning - prevents signal contention in multi-master systems |
| 2-V input tolerance | Accepts 3.3-V logic high levels directly - eliminates level-shifters in mixed-voltage backplane designs |
| 24-mA sink capability | Drives 10 standard TTL loads or 133-Ω terminated lines - supports longer trace lengths without signal degradation |
Applications
| Memory Address Buffering | Industrial Backplane Interface |
|---|---|
Use Scenario: Buffering 16-bit address lines between microprocessor and multiple memory chips on a single PCB. IC Role / Device Role / Timing Role: Non-inverting 3-state buffer isolating CPU address bus from memory modules during DMA cycles. Use Value: Prevents bus contention during memory access arbitration; 24 mA drive ensures signal integrity across 100-mm traces. | Use Scenario: Interfacing PLC I/O modules to a central controller over a 200-mm parallel backplane. IC Role / Device Role / Timing Role: Line driver translating TTL-level control signals across noisy industrial chassis wiring. Use Value: Input hysteresis rejects EMI-induced glitches; PNP inputs reduce cumulative loading on shared strobe lines. |
| LED Display Row Driver | Legacy Bus Repeater |
Use Scenario: Driving common-anode 8×8 LED matrix rows using multiplexed column scanning. IC Role / Device Role / Timing Role: High-current sink driver enabling 20-mA per segment with simultaneous 8-row activation. Use Value: 24 mA per output sustains brightness without external transistors; 18 ns tPHL supports >5 kHz refresh rates. | Use Scenario: Restoring signal integrity on a 300-mm ISA bus segment with >12 connected cards. IC Role / Device Role / Timing Role: Active repeater regenerating TTL waveforms between bus segments. Use Value: Low propagation delay (12–18 ns) and 400-mV noise margin maintain setup/hold timing across extended traces. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal non-inverting 3-state buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LS240NE4 | Inverting outputs (A→Y inversion); identical pinout, timing, and drive strength | Required where bus polarity must be inverted (e.g., complemented address decoding) | Select when logic inversion is needed; otherwise SN74LS244NE4 provides direct signal pass-through |
| SN74HC244N | CMOS technology; 2–6 V supply; 7.8 mA IOL at 5 V; 19 ns tPD; no hysteresis | Lower power (8 µA ICC), but reduced noise immunity and drive - unsuitable for long/noisy traces | Choose for battery-powered or low-power systems with clean signal environments; not drop-in for legacy LS bus loads |
Compared with SN74LS240NE4, SN74LS244NE4 avoids signal inversion critical for address/data integrity; versus SN74HC244N, it delivers higher drive and hysteresis essential for industrial backplanes - making it irreplaceable in noise-prone, high-fanout TTL systems.
Availability
SN74LS244NE4 is available at Aetrix Electronics and suitable for industrial control backplanes, legacy memory subsystems, and LED display drivers requiring stable component supply across extended product lifecycles.
Supply support for SN74LS244NE4 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 U.S.-based semiconductor company founded in 1930, specializing in analog, embedded processing, and logic ICs for industrial, automotive, and communications markets.
SN74LS244NE4 belongs to TI's legacy TTL logic family, engineered for robust bus interface and memory addressing in systems where reliability, noise immunity, and 5-V compatibility are prioritized over ultra-low power.
FAQ
What is the maximum operating temperature for SN74LS244NE4?
The SN74LS244NE4 is rated for commercial temperature operation from 0 °C to +70 °C. Its absolute maximum junction temperature is 150 °C, but sustained operation above 70 °C requires derating of output current and verification of thermal resistance (RθJA = 50.6 °C/W for PDIP package) with board-level heatsinking.
Does SN74LS244NE4 support 3.3-V input logic levels?
Yes, SN74LS244NE4 accepts 3.3-V logic high inputs reliably: its VIH specification is 2.0 V minimum, and actual threshold is typically 1.4 V with hysteresis. This allows direct interfacing with 3.3-V microcontrollers and FPGAs without level-shifting circuitry in mixed-voltage systems.
How should the output-enable pins (1G and 2G) be handled during power-up?
Both 1G and 2G pins must be held high during power-up to ensure outputs remain in high-impedance state until system initialization completes. TI recommends connecting each to VCC via a 10-kΩ pullup resistor to prevent bus contention caused by undefined enable states at power-on reset.
Can SN74LS244NE4 drive terminated transmission lines?
Yes, SN74LS244NE4 can drive 133-Ω terminated lines per TI's datasheet specification. Its 24-mA sink capability and 2.4-V VOH at –3 mA ensure adequate signal swing and edge integrity on controlled-impedance traces up to 30 cm in length under typical PCB stackups.
Is SN74LS244NE4 RoHS compliant?
SN74LS244NE4 is offered in both RoHS-compliant (lead-free) and legacy leaded versions. The 'NE4' suffix indicates the RoHS-compliant PDIP package with matte tin lead finish; full compliance documentation is available in TI's official product change notices and material declarations.
SN74LS244NE4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74LS
- Package/Case:
- 20-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Discontinued at Digi-Key
- 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:
- 15mA, 24mA
- Voltage - Supply:
- 4.75V ~ 5.25V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 20-PDIP
SN74LS244NE4 FAQ
1.How can I place an order for SN74LS244NE4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74LS244NE4 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 SN74LS244NE4 reliable?
The price and inventory of SN74LS244NE4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74LS244NE4 is usually 5 days.
3.What payment methods are accepted for SN74LS244NE4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74LS244NE4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74LS244NE4?
SN74LS244NE4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74LS244NE4 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 SN74LS244NE4?
For technical support, including SN74LS244NE4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74LS244NE4 requirements.
6.How does Aetrix verify that SN74LS244NE4 is sourced from the original manufacturer or authorized distributors?
All SN74LS244NE4 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 SN74LS244NE4 meets industry standards.
7.What is the process for return or replacement of SN74LS244NE4?
All SN74LS244NE4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74LS244NE4, 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 SN74LS244NE4 part is unused and in its original packaging.
Return procedure for SN74LS244NE4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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