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Home > Products > Integrated Circuits (ICs) > Logic > Buffers, Drivers, Receivers, Transceivers

onsemi DM74AS244WM

Name: DM74AS244WM
Brand: onsemi
SKU: DM74AS244WM
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: DM74AS244WM

Manufacturer:: onsemi

Category:: Buffers, Drivers, Receivers, Transceivers

Package:: 20-SOIC (0.295", 7.50mm Width)

Datasheet:: DM74AS244WM.pdf

Description:: IC BUF NON-INVERT 5.5V 20SOIC

Quantity:: RFQ Add To RFQ list

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Product details

Overview

DM74AS244WM from Fairchild Semiconductor is a non-inverting 3-STATE octal bus driver in 20-lead SOIC (M20B) package, designed for unidirectional data buffering in memory and microprocessor systems. It delivers 64 mA sink current, 15 mA source current, 6.2 ns max propagation delay (tPLH/tPHL), and operates across 4.5–5.5 V supply at 0°C to +70°C.

For engineers reviewing the DM74AS244WM datasheet, pinout, applications, or equivalent options, key selection criteria include 3-STATE enable timing (tPZL ≤ 7.5 ns), CMOS-compatible VOH (VCC − 2 V), and termination drive capability down to 133 Ω transmission lines.

Technical Context

The DM74AS244WM implements eight independent non-inverting buffers, each with individual input (A1–A8) and output (Y1–Y8), grouped into two sets of four sharing active-low 3-STATE enable inputs (G1̅, G2̅). Its oxide-isolated, ion-implanted Schottky TTL process enables faster switching than standard Schottky TTL while reducing power dissipation.

It is specified to drive 500 Ω loads with 50 pF capacitive load, supports CMOS interfacing via VOH ≥ VCC − 2 V, and maintains high-impedance outputs (IOZH ≤ 50 µA, IOZL ≥ −50 µA) when disabled - critical for bus contention avoidance in shared-data-path architectures.

Key Specifications

Parameter	Value and Actual Design Meaning
Supply Voltage	4.5–5.5 V - ensures compatibility with standard 5 V TTL/CMOS logic rails and margin against supply droop.
Output Drive Current	IOL = 64 mA (max), IOH = −15 mA (max) - sufficient to directly drive terminated transmission lines down to 133 Ω.
Propagation Delay	tPLH/tPHL ≤ 6.2 ns @ VCC = 4.5–5.5 V, CL = 50 pF - enables high-speed bus operation up to ~80 MHz clock-equivalent rates.
3-STATE Enable Timing	tPZL ≤ 7.5 ns, tPZH ≤ 9 ns - guarantees fast bus release and acquisition for time-critical multiplexed data transfers.
Input Thresholds	VIL = 0.8 V, VIH = 2.0 V - provides robust noise immunity and direct interface with LS-TTL and CMOS outputs.
Operating Temperature	0°C to +70°C - qualified for commercial-grade embedded control and computing applications.

Pinout & Package

DM74AS244WM uses a 20-lead SOIC package (JEDEC MS-013, 0.300" wide, Package Number M20B) with 1.27 mm pitch and thermal resistance θJA = 76.0°C/W.

Pin/Terminal	Circuit Role	Design Meaning
1, 2, 3, 4, 5, 6, 7, 8	A1–A8 Inputs	Non-inverting data inputs driving corresponding Y outputs when respective G̅ is LOW.
9, 10, 11, 12, 13, 14, 15, 16	Y1–Y8 Outputs	Buffered non-inverting outputs; enter high-impedance state when G1̅ or G2̅ is HIGH.
17, 18	G1̅, G2̅	Active-low 3-STATE enable controls for Y1–Y4 (G1̅) and Y5–Y8 (G2̅); both must be LOW for full output activation.
19	GND	Ground reference for all logic and output stages.
20	VCC	+5 V supply rail; powers internal logic and output drivers.

Key Features

Feature	Design Value
Advanced Schottky TTL Process	Oxide-isolated, ion-implanted fabrication enables higher speed and lower power vs. standard Schottky TTL.
Termination-Ready Output Drive	64 mA sink capability allows direct connection to 133 Ω transmission line terminations without external drivers.
CMOS-Compatible Output High	VOH ≥ VCC − 2 V ensures reliable logic HIGH recognition by 5 V CMOS devices under worst-case loading.
Dual Independent 3-STATE Control	Separate G1̅ and G2̅ pins allow selective enabling of upper/lower 4-bit segments - essential for nibble-oriented bus arbitration.

Applications

Memory Address Buffering	Microprocessor Data Bus Interface
Use Scenario: Driving address lines from a microprocessor to multiple memory ICs on a shared bus. IC Role / Device Role / Timing Role: Non-inverting 3-STATE buffer isolating CPU address outputs and enabling clean bus release during DMA cycles. Use Value: Prevents bus contention during memory access arbitration; 64 mA drive ensures signal integrity across multi-load PCB traces.	Use Scenario: Interfacing an 8-bit microprocessor data bus to peripheral controllers with different timing requirements. IC Role / Device Role / Timing Role: Unidirectional data latch/buffer with dual enable control for synchronized read/write handshaking. Use Value: Dual G̅ pins allow independent gating of upper/lower nibbles - supporting partial-word transfers and protocol-matched timing windows.
Backplane Signal Distribution	Legacy System Bus Expansion
Use Scenario: Distributing control signals across a 19-inch rack-mounted backplane with long trace runs. IC Role / Device Role / Timing Role: High-drive buffer compensating for capacitive loading and impedance mismatch on extended parallel buses. Use Value: Low propagation delay (≤6.2 ns) and 133 Ω termination support maintain signal edge fidelity over >15 cm traces.	Use Scenario: Upgrading legacy industrial controller I/O modules using existing 5 V TTL infrastructure. IC Role / Device Role / Timing Role: Pin- and function-compatible replacement for 74LS244 in retrofitted bus driver positions. Use Value: Drop-in performance upgrade: same pinout, improved speed (2× faster than LS), and lower power vs. original design.

Memory Address Buffering

Microprocessor Data Bus Interface

Use Scenario: Driving address lines from a microprocessor to multiple memory ICs on a shared bus.

IC Role / Device Role / Timing Role: Non-inverting 3-STATE buffer isolating CPU address outputs and enabling clean bus release during DMA cycles.

Use Value: Prevents bus contention during memory access arbitration; 64 mA drive ensures signal integrity across multi-load PCB traces.

Use Scenario: Interfacing an 8-bit microprocessor data bus to peripheral controllers with different timing requirements.

IC Role / Device Role / Timing Role: Unidirectional data latch/buffer with dual enable control for synchronized read/write handshaking.

Use Value: Dual G̅ pins allow independent gating of upper/lower nibbles - supporting partial-word transfers and protocol-matched timing windows.

Backplane Signal Distribution

Legacy System Bus Expansion

Use Scenario: Distributing control signals across a 19-inch rack-mounted backplane with long trace runs.

IC Role / Device Role / Timing Role: High-drive buffer compensating for capacitive loading and impedance mismatch on extended parallel buses.

Use Value: Low propagation delay (≤6.2 ns) and 133 Ω termination support maintain signal edge fidelity over >15 cm traces.

Use Scenario: Upgrading legacy industrial controller I/O modules using existing 5 V TTL infrastructure.

IC Role / Device Role / Timing Role: Pin- and function-compatible replacement for 74LS244 in retrofitted bus driver positions.

Use Value: Drop-in performance upgrade: same pinout, improved speed (2× faster than LS), and lower power vs. original design.

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal non-inverting 3-STATE bus driver applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
SN74AS244N	Same AS-family architecture, identical DC/AC specs, but in PDIP (N20A) package - θJA = 57.0°C/W vs. 76.0°C/W for SOIC.	Preferred where through-hole assembly or prototyping on breadboard/perfboard is required.	Select SN74AS244N for manual soldering, test fixtures, or legacy board rework where SOIC footprint is unavailable.
74F244PC	Fast TTL variant: slightly higher ICC (up to 95 mA), similar tPLH/tPHL (~5.5 ns), but no guaranteed VCC−2 V VOH compliance for CMOS interfacing.	Better suited for pure TTL-only systems; lacks explicit CMOS voltage-level guarantee of DM74AS244WM.	Choose 74F244PC only if system uses exclusively TTL loads and maximum speed is prioritized over CMOS interoperability.

Compared with SN74AS244N and 74F244PC, DM74AS244WM offers optimal thermal performance in surface-mount layouts, guaranteed CMOS-compatible VOH, and JEDEC-standard SOIC packaging - making it the preferred choice for space-constrained, mixed-logic industrial controllers.

Availability

DM74AS244WM is available at Aetrix Electronics and suitable for memory subsystems, microprocessor bus interfaces, backplane signal distribution, and legacy system upgrades requiring stable component supply and long-term obsolescence management.

Supply support for DM74AS244WM 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 discrete power products, acquired by ON Semiconductor in 2016.

The DM74AS244WM belongs to Fairchild's Advanced Schottky TTL logic family, engineered for high-speed, low-power bus interfacing in memory and microprocessor systems operating at 5 V.

FAQ

What is the logic function of DM74AS244WM?

The DM74AS244WM is a non-inverting octal 3-STATE bus driver. It contains eight independent buffers (A1→Y1 through A8→Y8), each enabled by one of two active-low 3-STATE controls (G1̅ for Y1–Y4, G2̅ for Y5–Y8). When enabled, outputs replicate inputs; when disabled, outputs enter high-impedance state. This functionality is confirmed in the device's function table and connection diagram in DS006298.

Is DM74AS244WM pin-compatible with 74LS244?

Yes, DM74AS244WM is functionally and pin-compatible with 74LS244 per Fairchild's datasheet DS006298, which explicitly states "Functional and pin compatible with 74LS and Schottky counterpart." Both use identical 20-pin SOIC (M20B) or PDIP (N20A) footprints and share identical pin assignments for A1–A8, Y1–Y8, G1̅, G2̅, VCC, and GND.

What is the maximum capacitive load DM74AS244WM can drive while maintaining specified timing?

DM74AS244WM switching characteristics are specified with CL = 50 pF, as stated in the "Switching Characteristics" table of DS006298. Propagation delays (tPLH/tPHL ≤ 6.2 ns) and enable/disable times are guaranteed only up to this load. Exceeding 50 pF may increase delay and degrade edge rate, requiring layout optimization or local buffering for heavier loads.

Does DM74AS244WM support mixed-voltage interfacing with 3.3 V CMOS devices?

No - DM74AS244WM is a 5 V-only device with VCC range 4.5–5.5 V and input thresholds (VIH = 2.0 V, VIL = 0.8 V) optimized for TTL/5 V CMOS. Its VOH is specified as ≥ VCC − 2 V (≥2.5 V min at VCC = 4.5 V), which falls below typical 3.3 V CMOS VIH (≥2.31 V), but not guaranteed for reliable 3.3 V system interfacing without level translation.

What is the thermal resistance (θJA) of DM74AS244WM in its SOIC package?

The DM74AS244WM in the M20B SOIC package has a typical junction-to-ambient thermal resistance (θJA) of 76.0°C/W, as published in the "Absolute Maximum Ratings" section of DS006298. This value assumes standard JEDEC test conditions (single-layer copper, 1 in² pad) and informs heatsinking requirements for continuous 3-STATE cycling or sustained output loading.

DM74AS244WM Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: 74AS

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, 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

DM74AS244WM FAQ

1.How can I place an order for DM74AS244WM through Aetrix?

Please submit a Request for Quotation (RFQ) for DM74AS244WM 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 DM74AS244WM reliable?

The price and inventory of DM74AS244WM are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DM74AS244WM is usually 5 days.

3.What payment methods are accepted for DM74AS244WM?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DM74AS244WM transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for DM74AS244WM?

DM74AS244WM orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your DM74AS244WM 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 DM74AS244WM?

For technical support, including DM74AS244WM datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DM74AS244WM requirements.

6.How does Aetrix verify that DM74AS244WM is sourced from the original manufacturer or authorized distributors?

All DM74AS244WM 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 DM74AS244WM meets industry standards.

7.What is the process for return or replacement of DM74AS244WM?

All DM74AS244WM units undergo pre-shipment inspection (PSI). If there is an issue with DM74AS244WM, 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 DM74AS244WM part is unused and in its original packaging.

Return procedure for DM74AS244WM:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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