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onsemi DM74AS244WMX
- Part No.:
- DM74AS244WMX
- Manufacturer:
- onsemi
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
DM74AS244WMX.pdf
- Description:
- IC BUF NON-INVERT 5.5V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,531
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Product details
Overview
DM74AS244WMX from Fairchild Semiconductor is an advanced Schottky TTL octal 3-STATE non-inverting bus driver in 20-pin SOIC (M20B) package, operating at 4.5–5.5 V, delivering ±64 mA output drive, 2 ns minimum propagation delay, and compatible with 74LS and Schottky logic families for memory and microprocessor bus interfacing.
For engineers reviewing the DM74AS244WMX datasheet, pinout, applications, or equivalent options, key selection criteria include unidirectional 3-STATE drive capability, CMOS interface compatibility (VOH = VCC − 2 V), low-impedance transmission-line driving down to 133 Ω, and industrial temperature range (0°C to +70°C).
Technical Context
This device implements eight independent non-inverting buffers, each with individual input (A) and output (Y), grouped into two sets of four, sharing common 3-STATE enable inputs (G). It uses oxide-isolated, ion-implanted Schottky TTL process to achieve improved speed-power trade-off versus standard Schottky TTL.
Switching performance is characterized into 500 Ω load with 50 pF capacitance; propagation delays are specified from A→Y (tPLH/tPHL ≤ 6.2 ns) and G→Y (enable/disable timing ≤ 9 ns), supporting high-speed bidirectional bus isolation in synchronous digital systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - ensures compatibility with standard 5 V TTL/CMOS logic rails |
| Output Drive Current | IOL = 64 mA, IOH = −15 mA - sufficient to drive terminated transmission lines down to 133 Ω |
| Propagation Delay | tPLH/tPHL ≤ 6.2 ns @ CL = 50 pF - enables operation in sub-100 MHz bus systems |
| Input Thresholds | VIL = 0.8 V, VIH = 2.0 V - matches standard TTL logic levels for seamless interfacing |
| 3-STATE Leakage | IOZL = −50 µA, IOZH = 50 µA - maintains signal integrity during high-impedance state |
| Operating Temperature | 0°C to +70°C - qualified for commercial and industrial embedded control environments |
Pinout & Package
DM74AS244WMX is housed in a 20-lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300-inch wide (Package Number M20B), with 1.27 mm pitch and surface-mount footprint.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4, 13, 14, 15, 16 | Buffer Inputs (A1–A4, A5–A8) | Non-inverting data inputs for eight independent drivers |
| 5, 6, 7, 8, 17, 18, 19, 20 | Buffer Outputs (Y1–Y4, Y5–Y8) | 3-STATE outputs capable of sinking 64 mA or sourcing 15 mA |
| 9, 10 | Enable Inputs (G1, G2) | Active-low enables for two groups of four buffers each |
| 11 | GND | Ground reference for all logic and output stages |
| 20 | VCC | Positive supply rail (4.5–5.5 V); pin 20 is VCC, not pin 1 - verified per DS006298 connection diagram |
Key Features
| Feature | Design Value |
|---|---|
| Advanced Schottky TTL Process | Oxide-isolated, ion-implanted fabrication enabling faster switching than standard Schottky TTL with lower power dissipation |
| CMOS Interface Compatibility | Specified VOH = VCC − 2 V allows direct interfacing with CMOS inputs without level-shifting circuitry |
| Transmission-Line Driving | Low output impedance supports termination down to 133 Ω, reducing reflections on PCB traces up to ~10 inches |
| Functional Pin Compatibility | Pinout and logic function match 74LS244 and 74S244, enabling drop-in replacement in legacy designs |
| Industrial Temperature Range | Guaranteed operation from 0°C to +70°C supports use in non-automotive industrial control and communications equipment |
Applications
| Microprocessor Bus Buffering | Memory Address/Data Latching |
|---|---|
Use Scenario: Isolating CPU address/data bus from peripheral devices during DMA or interrupt cycles. IC Role / Device Role / Timing Role: Unidirectional 3-STATE buffer providing controlled signal direction and bus contention prevention. Use Value: Enables clean bus arbitration with <6.2 ns propagation delay and 64 mA drive strength for reliable multi-drop signaling. | Use Scenario: Driving address lines to multiple SRAM or ROM chips in a shared-memory architecture. IC Role / Device Role / Timing Role: Non-inverting bus driver with dual enable groups (G1/G2) allowing selective chip-enable gating. Use Value: Supports simultaneous access to two memory banks via independent enable control, minimizing bus turnaround time. |
| Communications Backplane Interface | Legacy Peripheral Expansion |
Use Scenario: Interfacing UART or parallel port controllers to long backplane traces in industrial PLCs. IC Role / Device Role / Timing Role: Transmission-line driver with 133 Ω termination support and low-output-impedance output stage. Use Value: Reduces signal ringing and overshoot on 6–10 inch PCB traces, maintaining signal integrity at >10 MHz clock rates. | Use Scenario: Adding ISA or PC/104-compatible expansion slots to embedded x86 or 8051-based systems. IC Role / Device Role / Timing Role: TTL-compatible bus transceiver enabling legacy peripheral connectivity without level translation. Use Value: Maintains full 74LS244 functional and pin compatibility, allowing reuse of existing schematics and layout footprints. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74AS244N | Dual in-line package (PDIP), identical electrical specs and pinout; θJA = 57°C/W vs. 76°C/W for SOIC | Better thermal performance in through-hole prototyping or low-volume assembly; less suitable for high-density SMT | Select SN74AS244N when manual soldering, breadboarding, or thermal margin is critical over board space |
| 74ACT244SCX | Advanced CMOS (ACT) family; 4.5–5.5 V supply, but higher VOH (≥4.4 V), lower IOL (24 mA), and 3.5 ns typical tPD | Lower power, faster switching, but reduced drive strength limits transmission-line termination capability | Select 74ACT244SCX only where bus loading is light and speed outweighs drive requirement |
Compared with SN74AS244N and 74ACT244SCX, DM74AS244WMX offers optimal balance of high-current drive (64 mA), proven Schottky speed (≤6.2 ns), and SOIC packaging for modern SMT production-making it preferred for industrial bus buffering where signal integrity and layout density matter.
Availability
DM74AS244WMX is available at Aetrix Electronics and suitable for microprocessor bus buffering, memory subsystem interfacing, communications backplane design, and legacy peripheral expansion requiring stable component supply and long-term industrial availability.
Supply support for DM74AS244WMX 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 semiconductor company specializing in analog and mixed-signal ICs, power management, and logic families before its acquisition by ON Semiconductor in 2016.
The DM74AS244WMX belongs to Fairchild's Advanced Schottky TTL logic family, designed specifically for high-speed, low-power bus interface applications in memory, microprocessor, and communication systems.
FAQ
What is the function of DM74AS244WMX in a digital system?
DM74AS244WMX functions as an octal non-inverting 3-STATE bus driver, used to isolate, buffer, and drive data/address buses between microprocessors, memory, and peripherals. Its dual enable inputs (G1/G2) allow grouping of outputs into two sets of four, supporting selective bus control. The device is not bidirectional - unlike the DM74AS240, DM74AS244WMX provides unidirectional signal flow from A to Y only.
Does DM74AS244WMX support CMOS-level inputs?
Yes, DM74AS244WMX is specified to interface directly with CMOS logic: its VOH is guaranteed ≥ VCC − 2 V under load, meeting the minimum high-level output voltage required by most CMOS families. Input thresholds (VIH = 2.0 V, VIL = 0.8 V) remain TTL-compatible, ensuring robust noise margins when driven by either TTL or CMOS sources.
What is the maximum capacitive load DM74AS244WMX can drive reliably?
DM74AS244WMX switching characteristics are specified into 50 pF load with 500 Ω source resistance. While it can drive higher capacitance, signal integrity degrades beyond this point due to increased rise/fall times and potential ringing. For loads exceeding 50 pF, series termination or buffer staging is recommended - DM74AS244WMX itself does not include internal slew-rate control.
Is DM74AS244WMX pin-compatible with the 74LS244?
Yes, DM74AS244WMX is functionally and pin-compatible with the 74LS244, including identical pin assignments, logic behavior, and DC/AC specifications. This allows direct substitution in existing designs. However, DM74AS244WMX delivers higher output current (64 mA vs. ~8 mA for LS) and faster propagation (≤6.2 ns vs. ~20 ns), which may require review of termination and fanout in legacy layouts.
What is the thermal resistance (θJA) of the DM74AS244WMX SOIC package?
The DM74AS244WMX in the M20B SOIC package has a typical junction-to-ambient thermal resistance (θJA) of 76.0°C/W, as specified in the Absolute Maximum Ratings table. This value assumes standard JEDEC 2-layer board conditions; actual thermal performance depends on PCB copper area, airflow, and nearby heat sources - derating is required above 70°C ambient.
DM74AS244WMX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74AS
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- 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, 64mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
DM74AS244WMX FAQ
1.How can I place an order for DM74AS244WMX through Aetrix?
Please submit a Request for Quotation (RFQ) for DM74AS244WMX 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 DM74AS244WMX reliable?
The price and inventory of DM74AS244WMX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DM74AS244WMX is usually 5 days.
3.What payment methods are accepted for DM74AS244WMX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DM74AS244WMX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DM74AS244WMX?
DM74AS244WMX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DM74AS244WMX 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 DM74AS244WMX?
For technical support, including DM74AS244WMX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DM74AS244WMX requirements.
6.How does Aetrix verify that DM74AS244WMX is sourced from the original manufacturer or authorized distributors?
All DM74AS244WMX 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 DM74AS244WMX meets industry standards.
7.What is the process for return or replacement of DM74AS244WMX?
All DM74AS244WMX units undergo pre-shipment inspection (PSI). If there is an issue with DM74AS244WMX, 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 DM74AS244WMX part is unused and in its original packaging.
Return procedure for DM74AS244WMX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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