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Texas Instruments SN74ALS244C-1DBR
- Part No.:
- SN74ALS244C-1DBR
- Manufacturer:
- Texas Instruments
- Package:
- 20-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
SN74ALS244C-1DBR.pdf
- Description:
- PROTOTYPE
- Quantity:
- Payment:
- Shipping:
Inventory:2,517
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Product details
Overview
SN74ALS244C-1DBR from Texas Instruments is an octal 3-state buffer/line driver designed for memory address and bus driving in TTL-compatible systems. It features dual 4-bit noninverting buffers, 20-pin SSOP package, ±48 mA low-level output drive (IOL), 0°C to 70°C operating range, and pnp input structure reducing DC loading. It drives memory address registers and bidirectional data buses in industrial control backplanes.
For engineers reviewing the SN74ALS244C-1DBR datasheet, SN74ALS244C-1DBR pinout, SN74ALS244C-1DBR application, or SN74ALS244C-1DBR equivalent, key selection criteria include guaranteed 48 mA sink capability at VCC = 4.75–5.25 V, 3-state enable timing (tPZL ≤ 20 ns), SSOP-20 thermal and layout constraints, and compatibility with legacy ALS logic families.
Technical Context
The SN74ALS244C-1DBR implements two independent 4-bit noninverting buffer groups (1A→1Y and 2A→2Y), each controlled by a dedicated active-low 3-state enable input (1OE, 2OE). Its pnp input stage minimizes input current draw, enabling high fan-out without excessive loading on upstream drivers.
It operates strictly as a TTL-compatible device with VIH = 2 V, VIL = 0.8 V, VOH ≥ 2.4 V (IOH = –12 mA), and VOL ≤ 0.5 V (IOL = 48 mA). Propagation delays are specified at CL = 50 pF and R1/R2 = 500 Ω, with tPHL/tPLH ≤ 10 ns and disable-to-high impedance times (tPZL/tPZH) ≤ 20 ns.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | ALS (Advanced Low-Power Schottky) - ensures TTL compatibility with reduced power vs standard LS. |
| Output Drive (IOL) | 48 mA (min) - supports robust bus termination and long trace driving without external buffers. |
| Supply Voltage | 4.5 V to 5.5 V - compatible with standard 5 V TTL rails; absolute max 7 V. |
| Operating Temperature | 0°C to 70°C - commercial-grade rating suitable for industrial embedded and computing applications. |
| Propagation Delay | ≤10 ns (tPHL/tPLH) - enables reliable operation in 50 MHz address/data paths. |
| 3-State Enable Time | tPZL ≤ 20 ns, tPHZ ≤ 10 ns - ensures fast bus arbitration and clean signal isolation during direction switching. |
| Input Structure | pnp-based - reduces input current (IIL ≤ –0.1 mA), allowing >20-fan-out from standard TTL outputs. |
Pinout & Package
SN74ALS244C-1DBR uses a 20-pin SSOP (Shrink Small Outline Package) with 0.65 mm pitch, 7.5 mm × 5.6 mm body, and 2.0 mm max height. Pin 1 index area located at top-left corner per JEDEC MO-150.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | 1OE, 2OE | Active-low 3-state enable inputs - independently disable Group 1 (pins 3,5,7,9) or Group 2 (pins 12,14,16,18) outputs. |
| 3,5,7,9 | 1A1–1A4 | Group 1 noninverting input terminals - connect to upstream address/data lines. |
| 2,4,6,8 | 1Y1–1Y4 | Group 1 noninverting 3-state outputs - drive downstream bus segments or memory address inputs. |
| 12,14,16,18 | 2A1–2A4 | Group 2 noninverting input terminals - support parallel or mirrored signal routing. |
| 11,13,15,17 | 2Y1–2Y4 | Group 2 noninverting 3-state outputs - provide second independent buffered channel. |
| 10 | GND | Ground reference - must be low-impedance connection to minimize noise coupling into 3-state transitions. |
| 20 | VCC | Positive supply - decoupling capacitor (0.1 µF ceramic) required within 5 mm of pin. |
Key Features
| Feature | Design Value |
|---|---|
| High Sink Current Output | Guaranteed 48 mA IOL enables direct drive of unterminated 50 Ω transmission lines or multiple TTL loads. |
| pnp Input Stage | Reduces input current to ≤ –0.1 mA, minimizing loading on clock generators and microcontroller GPIOs. |
| Dual Independent Enables | Separate 1OE/2OE pins allow asymmetric bus control - e.g., hold one group active while disabling the other during arbitration. |
| Fast 3-State Switching | tPZL ≤ 20 ns and tPHZ ≤ 10 ns prevent bus contention during direction changes in half-duplex interfaces. |
| SSOP-20 Footprint | 7.5 mm × 5.6 mm body with 0.65 mm pitch offers 40% board area reduction vs PDIP-20 while maintaining thermal performance. |
Applications
| Memory Address Buffering | Industrial Backplane Interface |
|---|---|
Use Scenario: Driving 16-bit address bus between microcontroller and SRAM/Flash memory in programmable logic controllers. IC Role / Device Role / Timing Role: Noninverting 3-state buffer isolating CPU address outputs from memory chip select decoding logic. Use Value: 48 mA sink capability ensures stable logic levels across 15 cm PCB traces; dual OE allows dynamic address window partitioning. | Use Scenario: Interfacing multiple I/O modules to a central controller via shared 8-bit data bus in factory automation racks. IC Role / Device Role / Timing Role: Bidirectional bus driver enabling module hot-swap and fault isolation through independent 3-state control. Use Value: Fast tPZL ≤ 20 ns prevents bus glitches during module insertion; pnp inputs reduce controller GPIO loading. |
| Legacy System Bus Extension | TTL-Level Clock Distribution |
Use Scenario: Extending ISA or VMEbus address/data paths in retro-computing or test equipment upgrades. IC Role / Device Role / Timing Role: Octal repeater restoring signal integrity and fan-out capacity for aging backplane traces. Use Value: ALS family compatibility ensures seamless integration with 1980s–1990s TTL logic; SSOP-20 simplifies drop-in replacement of DIP packages. | Use Scenario: Distributing 10–25 MHz system clock to multiple synchronous peripherals (ADCs, DACs, FPGAs) with matched skew. IC Role / Device Role / Timing Role: Low-skew noninverting buffer providing identical propagation delay across all 8 outputs. Use Value: tPHL/tPLH ≤ 10 ns and tight unit-to-unit delay matching (<2 ns) maintain setup/hold margins across distributed clock domains. |
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 |
|---|---|---|---|
| SN74ALS244C-1DWR | SOIC-20 package (5.3 mm × 10.2 mm); same electrical specs and -1 drive rating. | Better thermal dissipation in high-density layouts; requires larger PCB footprint than SSOP. | Select when board space permits larger package and reflow profile supports SOIC. |
| SN74AS244ADWR | AS family: faster tPHL/tPLH (≤6.2 ns), higher IOL (64 mA), but increased ICC (60–90 mA). | Higher speed/power trade-off; not drop-in due to different VIH/VIL thresholds and AC characteristics. | Choose only when timing budget demands sub-7 ns propagation and power budget allows +2× quiescent current. |
Compared with SN74ALS244C-1DWR and SN74AS244ADWR, the SN74ALS244C-1DBR delivers optimal balance of compact SSOP-20 size, proven 48 mA drive, and low static power (ICC ≤ 27 mA), making it ideal for space-constrained industrial controllers where ALS compatibility and reliability are prioritized over marginal speed gains.
Availability
SN74ALS244C-1DBR is available at Aetrix Electronics and suitable for industrial control systems, legacy bus interface designs, and embedded memory subsystems requiring stable component supply and long-term obsolescence management.
Supply support for SN74ALS244C-1DBR 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 SN74ALS244C-1DBR belongs to TI's legacy ALS logic family, engineered for high-reliability, low-power TTL-compatible interfacing in industrial and computing infrastructure where compatibility, stability, and long-lifecycle support are critical.
FAQ
What is the maximum recommended output current for SN74ALS244C-1DBR?
The SN74ALS244C-1DBR is rated for a minimum low-level output current (IOL) of 48 mA under VCC = 4.75–5.25 V conditions. This is its defining "-1" version specification, distinguishing it from the standard SN74ALS244C (24 mA IOL). Exceeding 48 mA risks violating VOL limits and thermal derating.
Does SN74ALS244C-1DBR support mixed-voltage interfacing with 3.3 V logic?
No. The SN74ALS244C-1DBR is a 5 V-only TTL-compatible device with VIH = 2.0 V and VIL = 0.8 V. Its inputs are not 3.3 V tolerant, and driving it from 3.3 V sources may result in undefined logic states. Level-shifting circuitry is required for 3.3 V ↔ 5 V interoperation.
How does the pnp input structure benefit system design with SN74ALS244C-1DBR?
The pnp input stage reduces input current to ≤ –0.1 mA (IIL), enabling high fan-out - up to 20+ standard TTL outputs can drive a single SN74ALS244C-1DBR input without exceeding drive capability. This lowers loading on microcontrollers, CPLDs, and clock sources in dense address/data bus architectures.
Can SN74ALS244C-1DBR replace SN74LS244 in existing designs?
Yes, with qualification. The SN74ALS244C-1DBR offers identical pinout, function, and voltage thresholds as SN74LS244 but with improved speed (10 ns vs 15–20 ns), lower power (ICC ≤ 27 mA vs ~40 mA), and higher drive (48 mA vs 24 mA). Verify timing margins and thermal performance in the target application before substitution.
What is the meaning of "-1" in SN74ALS244C-1DBR?
The "-1" suffix denotes the enhanced output drive variant: SN74ALS244C-1DBR guarantees IOL ≥ 48 mA (vs 24 mA for standard SN74ALS244C), specifically validated for VCC = 4.75–5.25 V. This enables stronger bus driving and longer trace lengths without external buffering, confirmed in TI's SDAS142C datasheet Section 3.
SN74ALS244C-1DBR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ALS
- Package/Case:
- 20-SSOP (0.209", 5.30mm Width)
- 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, 24mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SSOP
SN74ALS244C-1DBR FAQ
1.How can I place an order for SN74ALS244C-1DBR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ALS244C-1DBR 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 SN74ALS244C-1DBR reliable?
The price and inventory of SN74ALS244C-1DBR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ALS244C-1DBR is usually 5 days.
3.What payment methods are accepted for SN74ALS244C-1DBR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74ALS244C-1DBR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74ALS244C-1DBR?
SN74ALS244C-1DBR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ALS244C-1DBR 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 SN74ALS244C-1DBR?
For technical support, including SN74ALS244C-1DBR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ALS244C-1DBR requirements.
6.How does Aetrix verify that SN74ALS244C-1DBR is sourced from the original manufacturer or authorized distributors?
All SN74ALS244C-1DBR 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 SN74ALS244C-1DBR meets industry standards.
7.What is the process for return or replacement of SN74ALS244C-1DBR?
All SN74ALS244C-1DBR units undergo pre-shipment inspection (PSI). If there is an issue with SN74ALS244C-1DBR, 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 SN74ALS244C-1DBR part is unused and in its original packaging.
Return procedure for SN74ALS244C-1DBR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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