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Texas Instruments SN74S244DWR
- Part No.:
- SN74S244DWR
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74S244DWR.pdf
- Description:
- IC BUF NON-INVERT 5.25V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,606
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Product details
Overview
SN74S244DWR from Texas Instruments is an octal non-inverting 3-state buffer/line driver in SOIC-20 package, designed for memory address and bus-oriented applications. It features two independent 4-bit channels (1A→1Y and 2A→2Y), 5-V operation, 7 ns typical propagation delay (tPLH/tPHL), ±64 mA output drive capability, and hysteresis-enhanced noise immunity. It is used to isolate and strengthen signals on high-capacity data buses in industrial control backplanes.
For engineers reviewing the SN74S244DWR datasheet, SN74S244DWR pinout, SN74S244DWR application, or SN74S244DWR equivalent, key selection criteria include its 3-state enable architecture, Schottky TTL-compatible input thresholds (VIH = 2 V, VIL = 0.8 V), high-current sinking (IOL = 64 mA), fast switching into 90-Ω loads, and compatibility with terminated transmission lines down to 133 Ω.
Technical Context
The SN74S244DWR implements dual 4-bit non-inverting buffers with active-low 3-state enable inputs (1G and 2G/2G). Each channel operates independently: when its G input is low, A-side inputs pass through to Y-side outputs; when high, all four outputs enter high-impedance state. Inputs use PNP structures to reduce DC loading on source buses.
It employs Schottky-clamped TTL logic (S-series), delivering higher speed than LS variants (7 ns vs. 18 ns tPLH/tPHL) and greater output current (64 mA vs. 24 mA IOL). Hysteresis (0.2–0.4 V) at inputs improves noise margins in electrically noisy environments such as motor drive or telecom backplane interfaces.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | SN74S244: Schottky TTL (S-series), not compatible with CMOS voltage levels |
| Supply Voltage | 4.75 V to 5.25 V - requires tightly regulated 5-V rail; out-of-range operation risks timing failure or latch-up |
| Propagation Delay | 7 ns max (tPLH/tPHL @ RL=90 Ω, CL=50 pF) - enables reliable operation on 100+ MHz bus edges with controlled routing |
| Output Drive | 64 mA sink (IOL), 15 mA source (IOH) - drives heavy capacitive loads and terminated stubs without external buffers |
| Noise Margin | 400 mV typical - achieved via input hysteresis and PNP input structure, critical for robustness in industrial EMI environments |
| Input Compatibility | Tolerates 2.5-V/3.3-V logic inputs (VIH ≥ 2 V, VIL ≤ 0.8 V) - allows direct interfacing with mixed-voltage systems without level shifters |
| Terminated Line Drive | Rated for 133 Ω terminated lines - supports point-to-point or daisy-chained bus topologies with impedance matching |
Pinout & Package
SN74S244DWR is supplied in a 20-pin SOIC (DW) package measuring 12.80 mm × 7.50 mm, with standard 1.27-mm pitch and gull-wing leads. The package is RoHS-compliant and rated for 0°C to 70°C ambient operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | 1G, 2G/2G | Active-low 3-state enable inputs - must be pulled low to activate respective 4-bit channel; tie to VCC via pullup for power-up safety |
| 2, 4, 6, 8, 11, 13, 15, 17 | 1A1–1A4, 2A1–2A4 | Non-inverting data inputs - accept TTL/CMOS-compatible logic; PNP input structure minimizes bus loading |
| 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 arbitration or standby |
| 10 | GND | Signal ground reference - must be low-impedance and separated from power ground in mixed-signal layouts |
| 20 | VCC | +5 V supply - requires local 100-nF ceramic decoupling adjacent to pin to suppress switching noise |
Key Features
| Feature | Design Value |
|---|---|
| Two independent 4-bit non-inverting buffers | Enables bidirectional bus segmentation - e.g., isolate CPU address bus from peripheral memory banks using separate 1G/2G controls |
| 3-state outputs with active-low enables | Allows time-multiplexed sharing of a single physical bus by multiple drivers without contention or external arbitration logic |
| Hysteresis on all inputs (0.2–0.4 V) | Increases noise immunity by >2× versus standard TTL, reducing false triggering in motor-drive or relay-switching environments |
| PNP input structure | Reduces input current draw to –400 µA (IIL), lowering source-driver loading and enabling fan-out to >20 LS-TTL loads |
| High-current sinking (64 mA) | Drives long PCB traces, LED arrays, or optocouplers directly - eliminates need for discrete transistor buffers in I/O expander designs |
Applications
| Memory Address Buffering | Industrial Backplane Interface |
|---|---|
|
Use Scenario: Buffering 16-bit address lines from microprocessor to multiple memory modules on a shared bus. IC Role / Device Role / Timing Role: Non-inverting 3-state buffer that isolates CPU address outputs and strengthens signal integrity across 15-cm routed traces. Use Value: Enables reliable read/write access to up to 4 memory banks using channel-select enables (1G/2G), while maintaining <7 ns skew between bits. |
Use Scenario: Interfacing PLC CPU modules with distributed I/O racks over extended backplane wiring. IC Role / Device Role / Timing Role: Bus line driver providing noise-immune signal regeneration between isolated subsystems. Use Value: 400-mV hysteresis and 133-Ω termination support prevent bit errors in 24-V industrial environments with frequent EMI transients. |
| LED Display Column Driver | Telecom Data Bus Repeater |
|
Use Scenario: Driving 8-column anodes in a 16×8 multiplexed LED matrix display. IC Role / Device Role / Timing Role: High-current sink driver for common-anode column selection, synchronized with row-scanning controller. Use Value: 64 mA per output sustains full-brightness LED drive without thermal derating, even at 1 kHz refresh rates. |
Use Scenario: Regenerating TTL-level data signals across a 30-cm telecom switch fabric backplane. IC Role / Device Role / Timing Role: Signal repeater restoring edge integrity and amplitude after trace loss. Use Value: 7 ns propagation delay and 90-Ω load drive ensure <1% jitter accumulation across 3-stage cascaded repeaters. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal non-inverting buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LS244DWR | Slower (18 ns tPLH), lower drive (24 mA IOL), LS-TTL family - consumes less ICC (max 54 mA vs. 160 mA) | Better suited for low-power, low-noise systems where speed <10 MHz; not recommended for terminated-line or high-fanout buses | Select SN74LS244DWR only if power budget is constrained and bus length <10 cm; verify VIH/VIL compatibility with driving logic |
| SN74HC244N | CMOS family, 2–6 V supply, 7.5 ns tPLH, 35 mA IOL - requires level translation when interfacing with 5-V TTL sources | Preferred for battery-powered or mixed-supply systems; unsuitable for direct connection to legacy 5-V TTL buses without translators | Choose SN74HC244N for new designs targeting wide VCC range and low static power; avoid in pure 5-V TTL ecosystems unless level-shifted |
Compared with SN74LS244DWR and SN74HC244N, the SN74S244DWR delivers superior drive strength and noise margin for industrial bus applications but demands higher supply current and strict 5-V regulation - making it optimal for legacy backplanes where signal integrity outweighs power efficiency.
Availability
SN74S244DWR is available at Aetrix Electronics and suitable for industrial backplane interfaces, memory address buffering, LED display column driving, and telecom data bus repeater applications requiring stable component supply and long-term obsolescence management.
Supply support for SN74S244DWR 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 founded in 1930, specializing in analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.
The SN74S244 belongs to TI's legacy TTL logic portfolio, engineered specifically for high-reliability bus interface and memory addressing in industrial control, telecom infrastructure, and instrumentation systems.
FAQ
What is the maximum operating temperature for SN74S244DWR?
The SN74S244DWR is specified for commercial temperature range operation from 0°C to +70°C. It is not rated for extended industrial (–40°C to +85°C) or military temperature grades. Operation outside this range may cause timing violations, increased leakage, or permanent parametric shift. Always verify ambient and junction temperatures using RθJA = 90.3°C/W and appropriate derating curves.
Does SN74S244DWR support 3.3-V logic inputs?
Yes, SN74S244DWR accepts 3.3-V logic inputs reliably: its VIH minimum is 2.0 V and VIL maximum is 0.8 V under recommended conditions. This allows direct connection to 3.3-V microcontrollers or FPGAs without level-shifting circuitry - provided the 5-V VCC rail remains stable and well-decoupled.
Can SN74S244DWR drive a 50-Ω transmission line?
No - SN74S244DWR is characterized for 90-Ω loads (CL = 50 pF) and rated for 133-Ω terminated lines. Driving a true 50-Ω line would exceed its IOL rating (64 mA) and cause excessive VOL rise (>0.8 V), violating logic thresholds. Use dedicated line drivers (e.g., SN65LVDS1) for 50-Ω differential or single-ended signaling.
What is the purpose of the hysteresis in SN74S244DWR inputs?
The built-in 0.2–0.4 V hysteresis on SN74S244DWR inputs widens the voltage gap between VIH and VIL thresholds, preventing oscillation or metastability when input signals transition slowly or experience noise-induced ringing. This is especially valuable in motor-control or relay-driven systems where bus lines are exposed to inductive kickback.
How should unused inputs and outputs be handled on SN74S244DWR?
Unused inputs must be tied to VCC or GND - never left floating - to prevent increased ICC and potential oscillation. Unused outputs should be disabled (G = HIGH) to avoid contention; if enabled, terminate them to VCC or GND with appropriate resistors. All unused 1G/2G pins must be pulled HIGH to maintain high-Z state during power-up.
SN74S244DWR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74S
- Package/Case:
- 20-SOIC (0.295", 7.50mm 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:
- 15mA, 64mA
- Voltage - Supply:
- 4.75V ~ 5.25V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
SN74S244DWR FAQ
1.How can I place an order for SN74S244DWR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74S244DWR 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 SN74S244DWR reliable?
The price and inventory of SN74S244DWR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74S244DWR is usually 5 days.
3.What payment methods are accepted for SN74S244DWR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74S244DWR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74S244DWR?
SN74S244DWR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74S244DWR 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 SN74S244DWR?
For technical support, including SN74S244DWR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74S244DWR requirements.
6.How does Aetrix verify that SN74S244DWR is sourced from the original manufacturer or authorized distributors?
All SN74S244DWR 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 SN74S244DWR meets industry standards.
7.What is the process for return or replacement of SN74S244DWR?
All SN74S244DWR units undergo pre-shipment inspection (PSI). If there is an issue with SN74S244DWR, 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 SN74S244DWR part is unused and in its original packaging.
Return procedure for SN74S244DWR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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