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onsemi DM74LS244WM
- Part No.:
- DM74LS244WM
- Manufacturer:
- onsemi
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
DM74LS244WM.pdf
- Description:
- IC BUF NON-INVERT 5.25V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,618
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Product details
Overview
DM74LS244WM from Fairchild Semiconductor is an octal 3-STATE noninverting buffer/line driver with PNP inputs, 24 mA sink current, 15 mA source current, and 12 ns typical propagation delay. It serves as a bus-oriented transmitter/receiver in memory-address and clock distribution circuits on industrial PC boards.
For engineers reviewing the DM74LS244WM datasheet, pinout, applications, or equivalent options, key selection criteria include 3-STATE output control timing (tPZH = 23 ns), hysteresis-enhanced noise immunity (0.4 V typical), drive capability for 133 Ω terminated lines, and SOIC-20 package compatibility with JEDEC MS-013 footprint.
Technical Context
The DM74LS244WM implements eight independent noninverting buffer channels, each with dual enable inputs (G1, G2) controlling 3-STATE output states. Its PNP input structure reduces DC loading on shared bus lines while providing 0.4 V typical hysteresis to suppress noise-induced switching at data inputs.
Each channel supports bidirectional bus interfacing via high-impedance outputs when disabled, with guaranteed VOH ≥ 2.4 V at IOH = −3 mA and VOL ≤ 0.4 V at IOL = 12 mA under VCC = 4.75–5.25 V and TA = 0–70°C operation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.75 V to 5.25 V - ensures stable TTL-compatible operation across standard 5 V supply tolerances |
| IOL / IOH | 24 mA sink / −15 mA source - drives heavy capacitive loads and terminated transmission lines down to 133 Ω |
| Propagation Delay | 12 ns typical (noninverting) - enables reliable timing in 33 MHz bus systems with margin |
| Hysteresis | 0.4 V typical - improves noise rejection on data lines in electrically noisy industrial environments |
| Enable Time tPZH | 23 ns max (CL = 45 pF) - supports fast bus arbitration cycles without output contention |
| Off-State Leakage | ±20 µA max - minimizes standby current in high-density bus configurations |
| Operating Temp | 0°C to +70°C - qualified for commercial-grade embedded control and instrumentation applications |
Pinout & Package
DM74LS244WM is housed in a 20-lead Small Outline Integrated Circuit (SOIC) package per JEDEC MS-013, 0.300 inch body width, with standard gull-wing lead form and 1.27 mm pitch.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 4, 5, 6, 7, 9, 10 | Data Inputs (A1–A8) | PNP-based TTL-compatible inputs with 0.4 V hysteresis for noise-immune signal reception |
| 3, 8, 11, 13, 14, 15, 16, 18 | 3-STATE Outputs (Y1–Y8) | Active-high noninverting drivers capable of 24 mA sink / −15 mA source into bus loads |
| 19, 20 | Output Enables (G1, G2) | Active-low enables controlling two groups of four outputs independently for bus partitioning |
| 12 | GND | Signal reference plane for all input thresholds and output voltage levels |
| 17 | VCC | 5 V power supply connection with 23 mA typical ICC (outputs enabled, all HIGH) |
Key Features
| Feature | Design Value |
|---|---|
| 3-STATE Output Control | Dual active-low enables (G1/G2) allow independent gating of two 4-bit bus segments without external logic |
| PNP Input Structure | Reduces input DC loading to <0.5 µA (IIL), minimizing bus line voltage droop during multi-driver contention |
| Hysteresis-Enhanced Inputs | 0.4 V typical VT+−VT− window prevents false triggering from EMI or ground bounce on shared address/data buses |
| High-Fanout Drive | 24 mA sink capability supports >20 LS-TTL loads or direct termination of 133 Ω transmission lines |
| Low Enable/Disable Timing | tPZH = 23 ns and tPHZ = 18 ns (CL = 45 pF) enable sub-40 ns bus turnaround in synchronous protocols |
Applications
| Memory Address Buffering | Clock Distribution |
|---|---|
Use Scenario: Driving 16-bit address bus from microcontroller to multiple SRAM/ROM chips on a dense PCB layout. IC Role / Device Role / Timing Role: Noninverting 3-STATE buffer isolating CPU address outputs and enabling memory chip select sequencing. Use Value: 24 mA drive strength ensures full logic swing across 15 cm traces; hysteresis rejects noise from adjacent data lines. | Use Scenario: Distributing a 10 MHz system clock to three peripheral controllers with matched trace lengths. IC Role / Device Role / Timing Role: Low-skew, fanout-capable clock driver maintaining edge integrity across parallel loads. Use Value: 12 ns propagation delay and 23 ns enable time support deterministic clock enable/disable in multi-phase timing. |
| Bus Transceiver Interface | Industrial I/O Expansion |
Use Scenario: Bidirectional data exchange between an ISA bus master and legacy peripheral cards using shared data lines. IC Role / Device Role / Timing Role: Direction-controlled line driver/receiver with independent group enables for half-duplex bus arbitration. Use Value: Dual enables (G1/G2) permit interleaved read/write cycles; ±20 µA off-state leakage prevents bus contention. | Use Scenario: Expanding GPIO count on a PLC mainboard by connecting discrete sensors and actuators to a local bus. IC Role / Device Role / Timing Role: Robust level-shifting buffer interfacing 5 V TTL logic to 24 V industrial field wiring via optocouplers. Use Value: PNP inputs tolerate induced transients up to 7 V; 0.4 V hysteresis suppresses contact bounce noise from mechanical switches. |
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 |
|---|---|---|---|
| SN74LS244N | Same electrical specs and pinout; PDIP-20 package instead of SOIC-20 | Through-hole assembly required; no surface-mount compatibility | Select for prototyping or legacy through-hole production where reflow is unavailable |
| MC74LS244N | Identical function and timing; Motorola-branded version with same JEDEC MS-001 footprint | No functional difference; long-term availability may vary by distributor channel | Choose based on supply chain preference when SOIC packaging is not mandatory |
Compared with SN74LS244N and MC74LS244N, the DM74LS244WM offers identical logic behavior and timing but delivers superior board density via its JEDEC MS-013 SOIC-20 package-critical for space-constrained industrial control modules requiring automated SMT assembly.
Availability
DM74LS244WM is available at Aetrix Electronics and suitable for memory-address buffering, clock distribution, and bus-oriented transmitter/receiver applications requiring stable component supply across industrial embedded and instrumentation programs.
Supply support for DM74LS244WM 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
Fairchild Semiconductor was a U.S.-based designer of analog and mixed-signal ICs, acquired by ON Semiconductor in 2016; its legacy logic portfolio remains widely deployed in industrial and computing infrastructure.
The DM74LS244WM belongs to Fairchild's 74LS logic family, engineered for high-speed, low-power TTL-compatible bus interfacing in memory, clock, and I/O expansion subsystems.
FAQ
What is the maximum operating temperature range for the DM74LS244WM?
The DM74LS244WM is rated for operation from 0°C to +70°C ambient temperature. This commercial-grade specification aligns with standard TTL logic requirements and supports use in office equipment, test instruments, and non-automotive industrial controls where extended temperature ranges are not mandated.
Does the DM74LS244WM support bidirectional data flow?
The DM74LS244WM is a unidirectional noninverting buffer: data flows only from A-inputs to Y-outputs. Bidirectional operation requires external control of G1/G2 enables and complementary receiver placement-unlike true transceivers, the DM74LS244WM does not integrate direction logic or internal feedback paths.
What is the purpose of the hysteresis in the DM74LS244WM inputs?
The DM74LS244WM incorporates 0.4 V typical hysteresis (VT+ − VT−) at each PNP input to widen the noise margin against voltage spikes and ground bounce. This design prevents metastability during signal transitions on shared buses, especially in systems with multiple simultaneously switching drivers.
Can the DM74LS244WM drive a 50 Ω transmission line directly?
No-the DM74LS244WM is characterized to drive terminated lines down to 133 Ω. Driving a 50 Ω load would exceed its 24 mA sink/−15 mA source rating and risk output stage degradation. For 50 Ω systems, a dedicated line driver IC or external series termination is required.
Is the DM74LS244WM pin-compatible with other 74LS244 variants?
Yes-the DM74LS244WM shares identical pinout and logic function with SN74LS244N (PDIP) and MC74LS244N (PDIP), differing only in SOIC-20 packaging. All variants use the same JEDEC-standard 20-pin assignment, including dual enables (G1/G2), eight A/Y pairs, VCC, and GND.
DM74LS244WM Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74LS
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- 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-SOIC
DM74LS244WM FAQ
1.How can I place an order for DM74LS244WM through Aetrix?
Please submit a Request for Quotation (RFQ) for DM74LS244WM 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 DM74LS244WM reliable?
The price and inventory of DM74LS244WM are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DM74LS244WM is usually 5 days.
3.What payment methods are accepted for DM74LS244WM?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DM74LS244WM transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DM74LS244WM?
DM74LS244WM orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DM74LS244WM 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 DM74LS244WM?
For technical support, including DM74LS244WM datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DM74LS244WM requirements.
6.How does Aetrix verify that DM74LS244WM is sourced from the original manufacturer or authorized distributors?
All DM74LS244WM 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 DM74LS244WM meets industry standards.
7.What is the process for return or replacement of DM74LS244WM?
All DM74LS244WM units undergo pre-shipment inspection (PSI). If there is an issue with DM74LS244WM, 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 DM74LS244WM part is unused and in its original packaging.
Return procedure for DM74LS244WM:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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