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Texas Instruments SN74S244N3
- Part No.:
- SN74S244N3
- Manufacturer:
- Texas Instruments
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
SN74S244N3.pdf
- Description:
- IC BUFFER NON-INVERT 5.25V 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,480
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Product details
Overview
SN74S244N3 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 dual 4-bit channels with independent active-low output-enable (1G, 2G), 64 mA sink capability per output, 7 ns typical propagation delay at 5 V, and compatibility with 3.3-V/5-V logic systems - used in server backplanes and telecom data buses.
For engineers reviewing the SN74S244N3 datasheet, SN74S244N3 pinout, SN74S244N3 application, or SN74S244N3 equivalent, key selection criteria include its 3-state bus-driving capability, Schottky TTL speed-power trade-off, thermal derating above 70°C, and direct replacement suitability in legacy LS/S-series memory interface designs.
Technical Context
The SN74S244N3 implements two independent 4-bit non-inverting buffers, each controlled by a dedicated active-low output-enable input (1G on Pin 1, 2G on Pin 19). Its Schottky-clamped TTL architecture delivers faster switching than standard LS variants while maintaining DC compatibility.
All eight outputs are 3-state capable with high-impedance disable states controlled solely by G inputs; no internal latching or direction control is present. Input hysteresis (0.2–0.4 V) and PNP input structure reduce DC loading and improve noise immunity on shared bus lines.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | Schottky TTL (S-series), compatible with 5-V supply and 3.3-V input logic levels |
| Propagation Delay (tPLH/tPHL) | 7 ns typical at VCC = 5 V, RL = 90 Ω, CL = 50 pF - enables high-speed bus buffering up to ~100 MHz edge rates |
| Output Sink Current (IOL) | 64 mA per output - drives terminated lines down to 133 Ω and supports fan-out to ≥20 LS loads |
| Input Hysteresis | 0.2–0.4 V - increases noise margin on noisy bus environments such as motor drive control backplanes |
| Supply Voltage Range | 4.75 V to 5.25 V - requires tight regulation; operation outside this range risks timing violation or latch-up |
| Operating Temperature | 0°C to +70°C - rated for commercial-grade industrial equipment, not extended or military temperature ranges |
| ESD Rating (HBM) | 500 V - meets JEDEC JS-001 Class 1A; handling requires standard ESD precautions |
Pinout & Package
SN74S244N3 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; both must be low for corresponding Y outputs to drive |
| 2, 4, 6, 8 | 1A1–1A4 | Non-inverting input signals for Channel 1; directly routed to outputs 1Y1–1Y4 when 1G = L |
| 11, 13, 15, 17 | 2A1–2A4 | Non-inverting input signals for Channel 2; directly routed to outputs 2Y1–2Y4 when 2G = L |
| 12, 14, 16, 18 | 1Y1–1Y4 | Non-inverting buffered outputs for Channel 1; high-impedance when 1G = H |
| 3, 5, 7, 9 | 2Y1–2Y4 | Non-inverting buffered outputs for Channel 2; high-impedance when 2G = H |
| 10 | GND | Signal and power ground reference - must be low-impedance connection to minimize ground bounce |
| 20 | VCC | +5 V supply - requires local 0.1 µF ceramic decoupling capacitor placed within 5 mm of pin |
Key Features
| Feature | Design Value |
|---|---|
| 3-State Outputs | Enables bidirectional bus sharing without external isolation; eliminates contention when multiple drivers share one trace |
| PNP Input Structure | Reduces input DC loading to ≤400 µA per A-input - minimizes voltage droop on weak-drive sources like microcontroller GPIO |
| Hysteresis on All Inputs | 0.2–0.4 V threshold separation improves noise immunity on long PCB traces or electrically noisy environments (e.g., motor drivers) |
| High Sink Drive (64 mA) | Drives 133-Ω terminated lines directly - eliminates need for external line drivers in telecom switch fabric interfaces |
| 5-V Supply Compatibility | Operates within 4.75–5.25 V window - matches standard TTL power rails and avoids level-shifter requirements in legacy systems |
Applications
| Memory Address Buffering | Server Backplane Signal Conditioning |
|---|---|
Use Scenario: Driving 20-bit memory address bus from microprocessor to SRAM/ROM chips across 100-mm PCB traces. IC Role / Device Role / Timing Role: Non-inverting 3-state buffer isolating CPU address outputs and enabling multi-drop address distribution. Use Value: 7 ns propagation delay ensures setup/hold timing margins at 12-MHz bus clock; 64 mA sink current maintains signal integrity into 50-pF trace + load capacitance. |
Use Scenario: Re-timing and strengthening control signals (e.g., reset, interrupt, enable) across 150-mm backplane in 1U rack-mounted server. IC Role / Device Role / Timing Role: Dual-channel bus repeater restoring signal amplitude and edge rate degraded by FR4 trace loss. Use Value: Input hysteresis rejects coupled noise from adjacent high-current power planes; PNP inputs prevent loading of upstream CPLD I/Os. |
| Telecom Line Driver | Industrial I/O Expander Interface |
Use Scenario: Driving differential line receiver inputs in T1/E1 framing circuitry where single-ended TTL signals must meet 133-Ω termination requirement. IC Role / Device Role / Timing Role: Impedance-matched line driver stage interfacing FPGA GPIO to legacy telecom PHY layer. Use Value: Guaranteed 64 mA sink capability allows direct drive into 133-Ω loads without external transistors - reduces BOM count and layout area. |
Use Scenario: Extending microcontroller GPIO count to drive 8 discrete LED indicators and 4 opto-isolator inputs in PLC module. IC Role / Device Role / Timing Role: General-purpose non-inverting buffer providing current gain and 3-state isolation between MCU and field-side peripherals. Use Value: Independent 1G/2G enables software-controlled grouping of outputs - e.g., disable LEDs during fault mode while keeping status lines active. |
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 |
|---|---|---|---|
| SN74LS244N | Lower drive (24 mA IOL), slower (18 ns tPLH), higher ICC (46 mA active), LS-family TTL | Acceptable where lower speed and reduced drive suffice; consumes less power in active state | Choose for cost-sensitive, low-speed industrial control where thermal budget is constrained |
| SN74ACT244N | CMOS technology, 5-V tolerant inputs, 24 mA IOL, 3.5 ns tPLH, wider VCC range (4.5–5.5 V) | Better noise immunity and lower static power, but lacks PNP input loading reduction and hysteresis | Prefer for new designs requiring lowest propagation delay and rail-to-rail logic compatibility |
Compared with SN74LS244N and SN74ACT244N, SN74S244N3 delivers superior speed and drive strength at the cost of higher active current and narrower supply tolerance - making it optimal for legacy high-performance bus interfaces where S-series timing is specified.
Availability
SN74S244N3 is available at Aetrix Electronics and suitable for memory address buffering, telecom line driving, server backplane signal conditioning, and industrial I/O expansion requiring stable component supply and long-term obsolescence management.
Supply support for SN74S244N3 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 company headquartered in Dallas, Texas, delivering analog and embedded processing solutions for industrial, automotive, and communications markets since 1930.
SN74S244N3 belongs to TI's legacy TTL logic portfolio, engineered specifically for high-speed, high-drive bus interface applications in memory systems and telecom infrastructure where Schottky TTL performance characteristics are required.
FAQ
What is the maximum operating temperature for SN74S244N3?
The SN74S244N3 is rated for commercial temperature operation from 0°C to +70°C. It is not qualified for extended (–40°C to +85°C) or military (–55°C to +125°C) ranges. Operation above +70°C risks timing violations and increased ICC, and thermal derating must be applied per RθJA = 50.6°C/W in the PDIP package.
Does SN74S244N3 support 3.3-V input logic levels?
Yes, SN74S244N3 accepts 3.3-V logic inputs reliably: its VIH(min) is 2.0 V and VIL(max) is 0.8 V under recommended conditions, allowing direct interfacing with 3.3-V CMOS outputs without level shifters - a key feature for mixed-voltage system design.
Can SN74S244N3 replace SN74LS244N in an existing design?
SN74S244N3 can replace SN74LS244N pin-for-pin and functionally, but requires verification of power supply stability (tighter 4.75–5.25 V window) and thermal management due to higher ICC (up to 160 mA active vs. 46 mA for LS). No PCB changes are needed if layout accommodates increased power dissipation.
What is the purpose of the hysteresis on SN74S244N3 inputs?
The 0.2–0.4 V input hysteresis on SN74S244N3 increases noise immunity by creating separate thresholds for rising and falling edges - critical for reliable operation on long, unterminated, or electrically noisy PCB traces common in industrial motor control and telecom backplanes.
How should unused inputs and outputs be handled on SN74S244N3?
Unused inputs must be tied to VCC or GND to prevent floating states that cause excess current and noise coupling; unused outputs should be left unconnected or disabled via their respective G inputs. Never tie unused outputs directly to VCC or GND while enabled.
SN74S244N3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74S
- 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:
- 15mA, 64mA
- Voltage - Supply:
- 4.75V ~ 5.25V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 20-PDIP
SN74S244N3 FAQ
1.How can I place an order for SN74S244N3 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74S244N3 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 SN74S244N3 reliable?
The price and inventory of SN74S244N3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74S244N3 is usually 5 days.
3.What payment methods are accepted for SN74S244N3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74S244N3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74S244N3?
SN74S244N3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74S244N3 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 SN74S244N3?
For technical support, including SN74S244N3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74S244N3 requirements.
6.How does Aetrix verify that SN74S244N3 is sourced from the original manufacturer or authorized distributors?
All SN74S244N3 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 SN74S244N3 meets industry standards.
7.What is the process for return or replacement of SN74S244N3?
All SN74S244N3 units undergo pre-shipment inspection (PSI). If there is an issue with SN74S244N3, 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 SN74S244N3 part is unused and in its original packaging.
Return procedure for SN74S244N3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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