My Inquiry
My Account
Texas Instruments SN74LS244DBR
- Part No.:
- SN74LS244DBR
- Manufacturer:
- Texas Instruments
- Package:
- 20-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
SN74LS244DBR.pdf
- Description:
- IC BUF NON-INVERT 5.25V 20SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,651
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SN74LS244DBR from Texas Instruments is an octal non-inverting 3-state buffer/line driver in SSOP-20 package, designed for memory address and bus interface applications. It features two independent 4-bit channels (1A→1Y and 2A→2Y), 5 V operation, 18 ns maximum propagation delay, ±24 mA output drive, and hysteresis-enhanced noise immunity. It is used to isolate and drive TTL/LS bus lines in industrial control backplanes.
For engineers reviewing the SN74LS244DBR datasheet, SN74LS244DBR pinout, SN74LS244DBR application, or SN74LS244DBR equivalent, key selection criteria include 3-state enable timing (tPZH/tPLZ), bus-drive capability into 133 Ω terminated lines, PNP input DC loading reduction, and compatibility with mixed 3.3 V/5 V logic systems during power sequencing.
Technical Context
The SN74LS244DBR 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 tolerate down to 2 V, enabling interoperability with 3.3 V logic sources.
Its PNP input structure reduces DC loading on upstream drivers, while built-in input hysteresis provides 400 mV noise margin. The device drives terminated transmission lines down to 133 Ω and supports bus-oriented receiver/transmitter roles in memory and I/O subsystems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.75–5.25 V - ensures stable TTL-level operation across commercial temperature range |
| Max Propagation Delay | 18 ns at VCC = 5 V, CL = 45 pF - enables reliable timing in 20 MHz bus systems |
| Output Drive | ±24 mA - sufficient to drive multiple LS loads or terminate 133 Ω transmission lines |
| Input Hysteresis | 0.2–0.4 V - improves noise immunity on shared bus lines in electrically noisy environments |
| 3-State Enable Time | tPZH ≤ 23 ns, tPLZ ≤ 20 ns - supports fast bus arbitration and dynamic line sharing |
| Input Voltage Tolerance | VIH = 2 V min, VIL = 0.7 V max - allows direct interfacing with 3.3 V CMOS outputs |
| Package | SSOP-20 (DB), 7.20 mm × 5.30 mm - surface-mount compatible with high-density PCB layouts |
Pinout & Package
SN74LS244DBR uses a 20-pin Small Outline Shrink Plastic (SSOP) package with 0.65 mm lead pitch. Pin 10 is GND; Pin 20 is VCC. Dual 4-bit channels are organized with separate active-low output-enable inputs (Pin 1 = 1G, Pin 19 = 2G).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (1G) | Channel 1 output enable | Active-low control: pulls all 1Y outputs to high-Z when high; enables 1A→1Y pass-through when low |
| 2,4,6,8 (1A1–1A4) | Channel 1 data inputs | Non-inverting inputs driving corresponding 1Y outputs; PNP structure minimizes upstream loading |
| 12,14,16,18 (1Y4–1Y1) | Channel 1 buffered outputs | 3-state outputs mirroring 1A inputs when 1G is low; high-Z when 1G is high |
| 11,13,15,17 (2A1–2A4) | Channel 2 data inputs | Independent 4-bit input group with identical electrical behavior to Channel 1 |
| 3,5,7,9 (2Y4–2Y1) | Channel 2 buffered outputs | Non-inverting outputs enabled by 2G (Pin 19); electrically isolated from Channel 1 |
| 10 (GND) | Ground reference | Common return path for all internal logic and output stages; must be low-impedance |
| 20 (VCC) | Power supply | +5 V supply for all internal circuitry; requires local 0.1 µF decoupling near the pin |
| 19 (2G) | Channel 2 output enable | Independent active-low control for Channel 2 outputs; enables bidirectional bus partitioning |
Key Features
| Feature | Design Value |
|---|---|
| 3-State Output Control | Independent active-low enables (1G/2G) allow per-channel bus arbitration without external logic |
| PNP Input Structure | Reduces input current to ≤0.2 mA, minimizing loading on clock generators and microcontroller GPIOs |
| Hysteresis-Enhanced Inputs | 400 mV noise margin prevents false triggering on EMI-prone backplane traces |
| Mixed-Voltage Interface | 2 V minimum VIH accepts 3.3 V logic levels directly-no level-shifter required in hybrid systems |
| Terminated Line Drive | Capable of driving 133 Ω parallel-terminated buses, supporting clean signal integrity over 15 cm PCB traces |
Applications
| Memory Address Buffering | Industrial Backplane Interface |
|---|---|
Use Scenario: Driving 16-bit address bus from microprocessor to multiple memory ICs on a single-layer industrial PCB. IC Role / Device Role / Timing Role: Non-inverting 3-state buffer isolating CPU address outputs and enabling memory chip select timing. Use Value: Prevents capacitive loading-induced timing skew; ±24 mA drive ensures setup/hold margins at 12 MHz bus speed. | Use Scenario: Interfacing PLC I/O modules via shared 8-bit data bus with daisy-chained termination. IC Role / Device Role / Timing Role: Bidirectional line driver/receiver with independent channel enables for slot-specific data routing. Use Value: PNP inputs reduce cumulative loading across 8 slots; hysteresis suppresses relay-contact bounce noise. |
| LED Display Row Driver | Legacy System Bus Extender |
Use Scenario: Scanning 8×8 LED matrix using multiplexed row/column addressing with constant-current sinks. IC Role / Device Role / Timing Role: High-current non-inverting buffer sinking up to 24 mA per row line to drive common-anode displays. Use Value: Eliminates need for discrete transistor arrays; 18 ns tPHL ensures flicker-free 1 kHz refresh rates. | Use Scenario: Extending ISA bus signals between legacy PC motherboard and custom expansion card with long trace runs. IC Role / Device Role / Timing Role: Signal repeater restoring edge rate and noise margin on 10 cm routed address/data lines. Use Value: Drives 133 Ω terminated lines to maintain signal integrity; 400 mV hysteresis rejects board-level switching noise. |
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 |
|---|---|---|---|
| SN74LS240DBR | Inverting outputs (A→Y inversion); same pinout, timing, and drive strength | Required where bus polarity inversion is needed for signal alignment or logic optimization | Select when system-level logic requires inverted buffering; otherwise SN74LS244DBR preferred for direct signal pass-through |
| SN74HC244PW | CMOS technology; 2–6 V supply; lower ICC (8 µA typ), higher VOH (4.9 V), but only ±7.8 mA drive | Suitable for low-power 3.3 V systems but cannot drive 133 Ω lines or LS loads | Choose for battery-powered or mixed-voltage 3.3 V designs; avoid where legacy TTL load drive or noise immunity is critical |
Compared with SN74LS240DBR, SN74LS244DBR provides non-inverting signal flow essential for address/data integrity; versus SN74HC244PW, it delivers superior noise immunity and bus-drive strength at the cost of higher static current and 5 V-only operation.
Availability
SN74LS244DBR is available at Aetrix Electronics and suitable for industrial control backplanes, legacy system upgrades, and LED display subsystems requiring stable component supply across extended product lifecycles.
Supply support for SN74LS244DBR 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.
The SN74LS244DBR belongs to TI's legacy TTL logic portfolio, engineered specifically to enhance density and performance of memory address drivers, clock distribution networks, and bus-oriented receivers in industrial and computing infrastructure.
FAQ
What is the maximum operating temperature range for the SN74LS244DBR?
The SN74LS244DBR is specified for commercial operation from 0 °C to +70 °C. Its thermal resistance (RθJA = 94.3 °C/W in DB package) requires adequate PCB copper area or airflow if operating near upper ambient limits with sustained output loading.
Can the SN74LS244DBR interface directly with 3.3 V microcontrollers?
Yes, the SN74LS244DBR accepts 3.3 V logic levels directly: its VIH minimum is 2.0 V and VIL maximum is 0.7 V, ensuring reliable recognition of 3.3 V CMOS outputs without level-shifting circuitry. This makes SN74LS244DBR ideal for mixed-voltage system integration.
How does the SN74LS244DBR handle bus contention during power-up?
The SN74LS244DBR outputs default to high-impedance only if 1G and 2G are held high via pullup resistors during power sequencing. Without external pullups, undefined G states may cause brief contention; TI recommends tying 1G and 2G to VCC through ≤10 kΩ resistors to ensure safe power-up behavior for SN74LS244DBR.
What is the recommended termination for SN74LS244DBR-driven transmission lines?
TI specifies that SN74LS244DBR can drive terminated lines down to 133 Ω. For optimal signal integrity on PCB traces >10 cm, use parallel termination at the far end: 133 Ω resistor from signal to ground (for single-ended) or 266 Ω across differential pairs. This matches the device's output impedance and suppresses reflections.
Does the SN74LS244DBR support hot-swap insertion?
No, the SN74LS244DBR is not hot-swap rated. Its absolute maximum ratings do not include live-insertion stress conditions, and uncontrolled VCC ramp-up may cause latch-up or excessive ICC. For hot-swap applications, consider dedicated hot-swap controllers upstream of SN74LS244DBR power rails.
SN74LS244DBR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74LS
- Package/Case:
- 20-SSOP (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:
- 15mA, 24mA
- Voltage - Supply:
- 4.75V ~ 5.25V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SSOP
SN74LS244DBR FAQ
1.How can I place an order for SN74LS244DBR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74LS244DBR 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 SN74LS244DBR reliable?
The price and inventory of SN74LS244DBR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74LS244DBR is usually 5 days.
3.What payment methods are accepted for SN74LS244DBR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74LS244DBR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74LS244DBR?
SN74LS244DBR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74LS244DBR 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 SN74LS244DBR?
For technical support, including SN74LS244DBR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74LS244DBR requirements.
6.How does Aetrix verify that SN74LS244DBR is sourced from the original manufacturer or authorized distributors?
All SN74LS244DBR 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 SN74LS244DBR meets industry standards.
7.What is the process for return or replacement of SN74LS244DBR?
All SN74LS244DBR units undergo pre-shipment inspection (PSI). If there is an issue with SN74LS244DBR, 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 SN74LS244DBR part is unused and in its original packaging.
Return procedure for SN74LS244DBR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SN74LS244DBR Tags
-
SN74LVC1G17DBVR
Texas Instruments
-
SN74LVC1G07DCKR
Texas Instruments
-
SN74LVC1G17DCKR
Texas Instruments
-
SN74LVC1G07DBVR
Texas Instruments
-
SN74LVC1G125DCKR
Texas Instruments
-
SN74AHCT1G126DBVR
Texas Instruments
-
SN74LVC1G125DBVR
Texas Instruments
-
SN74AHCT1G125DBVR
Texas Instruments
-
SN74LVC2G17DBVR
Texas Instruments
-
SN74LVC2G07DCKR
Texas Instruments
-
SN74LVC1G34DCKR
Texas Instruments
-
SN74LVC2G17DCKR
Texas Instruments
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
